US2298907A - Supervisory system - Google Patents

Description

Och 1942- c. E. STEWART SUPERVISORY SYSTEM Filed Feb. l, 1941 2 Sheets-Sheet 1 Inventor Glade E. Stewart,

b8 His Attorneg.

Oct. 13, 1942. c STEWART SUPERVISORY SYSTEM Filed Feb. 1, 1941 Z SheetS-Sheet 2 Inventor. Clyde E. Stewart, b9 flaw 1y 5. 1 444 4 1 His Attorney.

Patented Oct. 13, 1942 SUPERVISORY SYSTEM Clyde E. Stewart, Upper Darby, Pa., assignor to General Electric Company, a. corporation of New York Application February 1, 1941, Serial No. 377,033

32 Claims.

My invention relates to supervisory systems and particularly to supervisory systems in which means are provided whereby a current impulse of a character depending upon the position of a movable apparatus unit at a remote station is transmitted to a dispatchers oflice after a connection has been established between an apparatus unit and the corresponding signalling means at the dispatche'rs oflice. When the apparatus unit is a device which is adapted to be restored quickly to its normal position, when it is moved out of that position, such, for example, as an automatically reclosed circuit breaker, there i the possibility that the apparatus unit may be restored to its normal position beforethe supervisory apparatus can function to transmit a current impulse corresponding to the out-of-normal position of the operated unit. Consequently, when an indicating impulse is finally transmitted, it is of the character corresponding to the normal position of theunit and, therefore, no change in the signalling means at the dispatchers office is effected to inform the dispatcher that the apparatus unit has changed its position.

One object of my invention is to provide in a supervisory system an improved arrangement of apparatus whereby any change of an apparatus unit at the remote station from its normal position is permanently indicated at the dispatchers office until acknowledged by the dispatcher notwithstanding the fact that the apparatus unit may be restored to its normal position so quickly,

that no indicating impulse corresponding to the unit is transmitted while it is out of its normal position.

This application is a continuation-in-part of my copending application, S. N. 265,227, filed March 31, 1939, now abandoned.

My invention will be better understood from the following description when taken in connection with the accompanying drawings, Fig. 1 of which diagrammatically illustrates a supervisory system of the synchronous selector type embodying my invention, and Fig. 2 of which diagrammati-cally illustrates a supervisory system of the code selector type embodyin my invention, and the scope of my invention will be pointed out in the appended claims.

In Fig. 1 of the accompanying drawings, Lhave shown only as much of a complete synchronous selector supervisory system of the type disclosed in U. S. Letters Patent 1,945,665, granted Februmy 6, 1934, to the assignee of this application as is necessary for a complete understanding of the mote station (RS).

this type are well known in the art. As shown, the supervisory system includes three conductors L-l, Ir-2 and L-3 extending between a dispatcher's oflice DO and a remote station RS. The line conductors L-'l, L2 and L-3 are respectively called the common line, the indicating line, and the synchronizing line. The common line L-| interconnects the neutral terminal n of a battery B at the dispatchers oflice (DO) and the neutral terminal n of a battery B at the re- The indicating line L--2 interconnects the movable contact of a bank of contacts 1-81 of a switch I--S at the dispatchers oifice DO and the movable contact of a bank of contacts l-SI of a switch |--S' at the remote station RS. The synchronizing line L-3 interconnects the movable contact of a bank of contacts l-SS of the switch l-S and the movable contact ot a bank of contacts I--SS' of the switch I S' at the remote station. The switch l-S, as shown, is a selector switch of the well known rotary type comprising several banks of stationary contacts and indicated here as: I SN, l-- SS, ISI, l--ST, l-SC, and l-SM, each of which has a movable contact mounted on a common rotatable member which is arranged to be rotated by a motor magnet 'l-SM in a manner well known in the art each time themagnet l-SM i deenergized. The switch l-S' is a similar switch comprising five banks of stationary contacts: l--S'N', l-S'S', IS'I', I-ST and I-SC, and a motor magnet IS'M' for simultaneously rotating the cooperating movable contacts for the five banks of stationary contacts.

In actual practice the switches I-S and 1-45 usually have 25 positions, but in order to simplify the disclosure they are shown as having only 6 positions.

At the remote station RS there are a number of apparatus units, the positions of which are to be indicated at the dispatchers ofiice DO. Each of these apparatus units is allotted to different corresponding predetermined positions of the switches 1-8 and l-S', but in order to simplify the disclosure, only the apparatus unit A'U'-3, associated with the third ofi-normal positions of the switches IS and l-S', is shown. This apparatus unit AU'--3 is shown as an automatically reclosed circuit breaker having aclosing coil 2, a trip coil 3, and a latch 4 for holding the circuit breaker in its closed position. The trip coil 3 is connected in series relation with an electric circuit 5 containing the circuit breaker AU'-3 so that, when the current in the circuit present invention because supervisory systems of 5 exceeds a predetermined value, the latch 4 is released to allow the circuit breaker to open. As soon as the circuit breaker A'U'3"has opened so that its auxiliary contacts 6 ar closed and the latch 4 is restored to its latching position, a circuit is completed for the closing coil 2 t reclose the circuit breaker if a switch 1 associated therewith is also closed.

Associated with the apparatus unit AU'-3 at the remote station is an indicating relay I'A'-3 which is normally in its energized position and which is arranged to be deenergized in response to any change in the position of the apparatus until A'U'3 whenever the relay IA'3 is energized. The normally energized circuit for the relay IA'-3 includes the contacts I of the relay IA3 and either the contacts II or the contacts, l8 of the circuit breaker I depending upon the position of the circuit breaker A'U'3 when the last indicating impulse corresponding thereto was transmitted to the dispatcher's ofiice.

' At the dispatchers oflice DO there is provided for each apparatus unit an individual set of three signal lamps such as LR3, LG-3 and LW3 for the apparatus unit A'U'3. When the lamp LR3 is lighted, it indicates that the circuit breaker A'U'3 is closed, and when the lamp LG-3 is lighted, it indicates that the circuit breaker A'U'3 is open. The lamp LW3, when lighted simultaneously with either of the other two lamps, indicates that the position of a two-position disagreement key DK3, which is individual to the circuit breaker A'U'3, does not agree with the position of the circuit breaker A'U'3 as indicated by the lamps LR.3 and LG3. When the lamp LW3 is lighted, it can be extinguished by moving the associated disagreement key DK3 to its other position.

The lighting of the lamps LR--3, LG3 and LW3 is controlled by a two-position polarized indicating relay IR,3, which is individual to the apparatus unit A'U'3, and the winding of which is interconnected between the neutral terminal n of the battery B and the third off-normal contact of bank i-SI. Since the third ofi-normal contact of the bank I-S'I is arranged to be connected to the positive terminal of the battery B at the remote station when the circuit breaker A"U-3 is closed and to the negative terminal of the battery B when the circuit breaker A'U'3 is open, it is evident that the direction of the current flow through the winding of the polarized relay IRr 3 when the circuit of this relay is completed over the indicating line L2 in the third off-normal position of the switches IS and |S' depends upon the position of the apparatus unit AU3 at that time.

Normally the switches IS and l-S' are at rest in the positions in which they are shown in the drawings and synchronous operation of these switches from these normal positions may be started by either momentarily closing a manually operated start switch ST at the dispatchers oflice or by any one of the apparatus units at the remote station changing its position and thereby effecting the deenergization of the associated indicating relay. When the start switch ST is closed, it completes through the normal contacts of banks l-SI and l-S'I' and the indicating conductor L2 an energizing circuit for a start relay A at the remote station which in turn by closing its contacts I2 completes through the normal contact of banks l-S'S and l-SS and the synchronizing line L-3 an energizing circuit for the polarized selector synchronizing relays S'SR' and SSH. These synchronizing relays effect in a manner disclosed in the aforesaid Letters Patent 1,945,665 the synchronous operation of the motor magnets l-SM and I--SM to move the switches I-S and |S to their first off-normal positions.

When any one of the apparatus units at the remote station changes its position so that the associated indicating relay is deenergized, such as the indicating relay I'A'3 associated with the apparatus unit A'U'3, an energizing circuit is completed for a second starting relay AA at the remote station. By closing its contacts l4, which are in parallel with the contacts l2 of the start relay A, relay A'A' completes the energizing circuit of the selector synchronizing relays SS'R' and SSR to start the synchronous operation of the switches 1-8 and i-S'. After being started, the synchronous operation of the switches I-S and I-S' continues until the switches either are restored to their normal positions or reach positions in which either the corresponding select key at the dispatchers office is out of its normal position or the corresponding indicating relay at the remote station is deenergized. For example, if the select key SK3, which is individual to the apparatus unit A'U'3, is operated, the circuit through the synchronizing line L3 is open when the switch l--S reaches its third oil-normal position. If the indicating relay IA3 is deenergized, the circuit through the synchronizing line L3 is open at the contact l6 of the relay I'A'3 when the switch I-S reaches its third ofi-normal position. Therefore both of the switches |S and |-S' will stop in their third off-normal positions if either the select key SK3 is in its operated position or the indicating relay IA'-3 is deenergized. However, if the select key SK-3 is in its normal position and the relay I'A'3 is energized when the switches IS and IS' reach their third off-normal positions, the energizing circuit for the selector synchronizing relays SSH and S'SR' is immediately completed to effect the movement of both of the switches to their fourth off-normal positions.

Whenever both of the switches I-S and l--S' are simultaneously in their third oil-normal positions, a circuit is completed for the indicating relay IR,3 at the dispatchers office through the indicating line L2 and the resistor l9 to the positive terminal of the battery B through contacts ll of apparatus unit A'U'3, if it is closed, or to the negative terminal of the battery B through the contacts l8 of the apparatus unit A'U'3, if it is open. Therefore, if the apparatus unit A'U--3 is closed, the polarized relay IRr-3 is operated to the position in which it is shown so as to eiTect the lighting of the lamp LR-3, whereas if the apparatus unit A'U'3 is open, the relay IR3 is operated to its other position in which it effects the lighting of the lamp LG3. The lamp LW3 is lighted in case the position of the disagreement key DK3 does not agree with the position of the apparatus unit A'U'3 as indicated by the lamps LR-3 and LG-3.

Since the apparatus unit A'U-3 may open and reclose before the switches I--S and l-S can reach their third off-normal positions after the relay IA'3 is deenergized in response to the opening of the apparatus unit, it is evident that, when the indicating impulse corresponding to the apparatus unit is transmitted after such an operation thereof, it will be of such a character as to effect no change in the lighting of the lamps LRr-3 and LW3 as the lamp LR-3 will continue to indicate that the apparatus unit A'U'3 is in its closed position and thedisagreement key DK-3 is still in its position corresponding to the closedposition of the associated apparatus unit. In order that the dispatcher may be. informed of such an automaticoperation of the apparatus unit A'U'-3, I provide in the embodiment of my invention shown in the drawings an arrangement for flashing one ofthe associated lamps, such as the lamp LW-3, after any such.reclosing operation of the apparatus unit AU'--3. This result is accomplished by providing at the dispatchers oflice, for each apparatus unit at the remote station, an individual relay which is energized whenever theswitches l-S and l--S' remain in the positions thereof allotted to the corresponding apparatus unit for a predetermined time which is longer than the time they remain in the same position when there has been no change in the position of the corresponding apparatus unit since the last indicating impulse thereof was transmitted. For the apparatus unit AU'-3. this relay is H-3, the energizing circuit of which is arranged to be completed through the contacts 3 of l--SM, 2!! of a relay and the contacts 2| of a time relay D when the switch |S remains in its third off-normal position for a predetermined length of time. The circuit of the time relay D is controlled so that, during the synchronous operation of the switches l-S and l-S, it cannot pick up and close its contacts 2|, but whenever the switches remain in any one of their offnormal positions for a predetermined time, the relay D operates to close its contacts 2| and open its contacts 22 in an energizing circuit for the relay C which is arranged to open its contacts 20 a predetermined time after it is deenergized. Therefore. the original energizing circuit of the relay H-3 is completed for only a short period of time.

whenever the switches |-S and l -S' are stopped in their third oiT-normal positions. By closing its contacts 24 the relay H3 completes a locking circuit for itself through contacts 25 of the select key SK-3 if it is in its normal position, contacts 26 of the disagreementkey DK--3 if it is in its position corresponding to the closed position of the apparatus unit AU'-3. and contacts 21 of the indicating relay IR-3 if it is in its position corresponding to the closed position of the apparatusunit AU'-3. Relav H-3, therefore, is energized in case the switches l--S and l--S' are stopped in their third offnormal positions due to an automatic o ening and reclosing of the apparatus unit A'U'--3 before an indicating impulse corresponding to.

the open position of the apparatus unit can be transmitted. If the apparatus unit AU'-3 remains open long enough so that an indicating impulse corresponding to the open position of the apparatus unit is transmitted, the indicating relay IR-3 at the dispatchers ofiice is operated by this indicating impulse so that it occupies its other position and thereby opens the locking circuit for the relay H-'-3. Therefore, the relay H--3 becomes deenergized as soon as the relay C opens its contacts 20 after the switches l-S and l--S' have stopped in their third off-normal positions.

At the remote station a time relay D is provided which is arranged to pick up and close its contacts 26 whenever the switch i-S' is stopped in any of its off-normal positions. Therefore. When the switch 'I-S' stops in its third off normal position due to an automatic operation of the apparatus unit AU'-3, which also effects the deenergization of the asociated relay I'A'3, a circuit is completed for a time relay H'-3. After being energized for a predetermined time, the relay H'3 completes an energizing circuit for the deenergized indicating relay IA3 and also completes a circuit for the synchronizing relays SSR and S'S'R' so that the synchronous operation of the switches l-S and I-S' is again started to restore them to their normal positions.

When the switch l-S is restored to its normal position, a circuit is completed through the normal contact of bank |-ST at the dispatchers ofiice for a control relay E. If the relay H-3 is energized when the relay E becomes energized, a circuit is completed for a relay F which in turn completes a flashing circuit for the lamp LW--3 through an interrupter IR so that the lamp LW--3 is intermittently lighted at the same time the lamp LIL-3 is continuously lighted. This combination of lamps informs the dispatcher that the apparatus unit AU'-3 has opened and automatically reclosed. By moving the disagreement key DK--3 to the position thereof corresponding to the'open position of the apparatus unit A'U'3, the dispatcher can effect the deenergization of the relay H--3 so as to stop the intermittent lighting of the lamp LW-3 and cause it to be lighted continuously. Then by moving the disagreement key DK-3 back to the position thereof corresponding to the closed position of the apparatus unit A'U3, the dispatcher can extinguish the lamp LW-3 completely.

The operation of the arrangement shown in the drawings is as follows:

When the switches |S and 1-8 are at rest in their normal positions and the apparatus unit AU'-3 is closed, the various control devices of the supervisory equipment occupy the positions in which they are shown in the drawmgs. circuit for the relay E is completed through the normal contact of bank l-S'I and an energizing circuit is completed for the relay C through the contacts 22 of the deenergized relay D. A circuit is completed for the lamp LR-3 through the contacts 30 of the indicating relay IRP-3 so that this lamp is continuously lighted thereby informing the dispatcher that the apparatus unit A'U-3 at the remote station is closed. At the l remote station the indicating relay I'A'3 is energized by a locking circuit which includes the contacts In of the relay I'A'-3 and the auxiliary contacts I! of the closed apparatus unit A'U '-3.

It will be assumed first that the start switch ST is closed momentarily to'complete an energizing circuit for start relay A through the normal contacts of bank I-SI and l-SI' and the indicating line L-2. By closing its contacts l2, relay A completes through the normal contacts of banks l-SS and |-s's' its the synchronizing line L--3 an energizing circuit for the synchronizing relays SSH. and S'SR' which effect in a 'well known manner the synchronous operation of the switches l-S again reach their normal positions in case all of the indicating relays at the remote station are energized and all of the select keys at the dispatchers office are in their normal positions. When the switches I-S and l-S' reach their third off-norma1 positions, an energizing circuit At the dispatchers office an energizing and IS' until they.

immediately completed through the contacts l5 of the select key SK-3 at the dispatchers oflice and the contact I6 of the energized indicating relay I'A3 at the remote station so that the switches immediately move to their fourth ffnormal positions. During the short time that the switches [-8 and IS' are in their third offnormal positions, an indicating impulse is transmitted over the indicating line L2 to the indicating relay IR3 at the dispatchers oifice through the resistor l9 and the contacts I! of the closed apparatus unit AU--3. This indicating impulse is of such a character, however, that the relay lR-3 remains in the position in which it is shown so that the lamp LR3 remains continuously lighted.

It will now be assumed that, while the switches I-S and l--S are at rest in their normalpositions, the apparatus unit AU'-3 automatically opens so that its contacts I] interrupt the holding circuit for the associated indicating relay I'A3. By closing its contacts l3, relay I'A3 completes an energizing circuit for the start relay AA' which in turn starts the synchronous operation of the switches l-'-S and l-S by closing its contacts I4. Synchronous operation of the switches l--S and IS then continues until they reach their third oiT-normal positions where they stop because the synchronizing circuit is open at the contact l6 of the deenergized indicating relay I'A3.

A circuit is completed for a time relay D at the dispatchers oflice to the opposite terminals of the battery B through alternate ofi-normal contacts of the bank l-SC, and a circuit is completed for the time relay D at the remote station to the opposite terminals of the battery B through alternate oil-normal contacts of bank l-SC so that, during the synchronous operation of the switches IS and IS', the currents through the relays D and D' are reversed at such a rate that they cannot pickup. However, when the switches I-S and I-S remain in any off-normal position for a predetermined time which is longer than the time they remain therein during normal synchronous operation, the relays D and D have time to pick up. Therefore, when the switches IS and l-S' reach their third offnormal positions due to the deenergization of the indicating relay I'A3, the relays D and D are energized for a suflicient length of time pick up. By opening its contacts 22, relay D opens the circuit of relay C and by closing its contacts 2|, relay D completes an energizing circuit for relay H--3 through contacts 20 of relay C and the third off-normal contact of bank l-SM. By closing its contacts 24, relay H3 completes a locking circuit for itself through contacts 25 of the select key SK3, contacts 26 of disagreement key DK3 and contacts 21 of relay IR3.

At the remote station the closing of the contacts 26 of the relay D completes an energizing circuit for the relay H--3 through the third offnormal contact of bank l-ST' and contacts 3| of the deenergized indicating relay I'A3. After a time interval, relay 1-1-3 closes its contacts 32 and 33. The closing of the contacts 32 reestablishes the synchronizing circuit so that the synchronizing relays SSR and S'SR' are again energized to start the synchronous operation of the switches IS and I'S'. The closing of the contacts 33 of the relay H-3 completes an energizing circuit for the indicating relay I'A3 through the contacts 26 of relay D, the third 01T- normal contact of bank IS'T', and either contacts I! or l8 of the apparatus unit A'U'3 depending upon the position of this unit. By closing its contacts "I, the relay I'A3 completes a holding circuit for itself. Since the contacts 33 of relay H'3 reestablish the synchronizing circuit after the switches IS and I-S' have remained in an oif-normal position for a predetermined time due to the deenergization of the indicating relay associated with the off-normal position, it will be evident that the relay I-I'3 prevents the supervisory equipment from becoming stalled in an off-normal position due to the auxiliary contacts I! or 18 of the corresponding apparatus unit failing to close and complete the energy circuit for the associated indicating relay.

If the apparatus unit AU3 is still open when the switches IS and |-S' stop in their third ofi-normal positions in response to an automatic opening of the apparatus unit A'U'--3, a circuit is completed for indicating relay IR,--3 through the third off-normal contact of bank l-SI, indicating conductor L-2, third ofi-normal contact of bank l--S'I, resistor 19, contact I8 of the open apparatus unit AU'-'3 to the negative terminal of battery B. This indicating impulse is of such a character that the indicating relay IR3 moves to its other position so that the contacts 21 and 30 are opened and the contacts 34 are closed. The opening of the contacts 21 interrupts the locking circuit of the relay H3 so that this relay becomes deenergized as soon as the time relay C opens its contacts 20 in the original energizing circuit for relay H-3. The opening of the contacts 30 extinguishes the lamp LR-3, and the closing of the contacts 34 completes a circuit for lamp LG-3 directly across the terminals of the battery B and a circuit for the lamp LW-3 across the terminals of the battery B through contacts 35 of relay 1-1-3 when it is in its deenergized position and contacts 36 of the disagreement key DK3. The continuous lighting of the lamps LG--3 and LW3 informs the dispatcher that the apparatus unit A'U-3 has opened and is still in its open position. By moving the disagreement key DK3 to its other position, the circuit of the lamp LW--3 is opened so that only the lamp LG-3 remains lighted.

It will now be assumed that, after the apparatus unit A'U'-3 opens, it is immediately reclosed andis in its closed position when the switches |S and IS are stopped in their third ofi-normal positions in the manner above described. Under these conditions, the indicating circuit for the indicating relay IR3 in the third off-normal positions of the switches l-S and lS' is connected to the positive terminal of the battery B by the auxiliary contact I! of the closed apparatus unit AU3. Therefore, when this indicating impulse is transmitted, it does not change the position of the indicating relay IR3. Consequently, the locking circuit of the relay I-I--3 remains completed when the synchronous operation of the switches l-S and l-S is again started by the energization of relay H'3 at the remote station in the manner heretofore described.

As soon as the switches lS and l-S' reach their normal positions and the relay E becomes energized, the closing of its contacts 31 completes through contacts 38 of the energized relay H3 an energizing circuit for relay F. The closing of the contacts 39 of relay F completes a locking circuit for the relay F around the contacts 31 of relay E, and the closing of the contacts 40 of relay F completes a flashing circuit for the lighted.

In case the dispatcher fails to acknowledge th transmission of an indicating impulse corresponding to the open position of the apparatus unit A'U--3, by moving the disagreement key DK3 to the position thereof corresponding to the open position of the apparatus unit AU'3, before. it is automatically reclosed and an indicating impulse corresponding to the closed position is subsequently transmitted, it is evident that the lookin circuit of relay F is completed in response to the transmission of the indicating impulse corresponding to the closed position of the unit. Therefore, when the switches 1-3 and l-S' return to their normal positions, the lamp LW3 is intermittently lighted until the dispatcher operates the disagreement key DK-3 in the manner above described.

In case the dispatcher desires to manually control from the dispatchers oiiice the apparatus unit AU-3, he opens -the select key SK3 before momentarily operating the start key ST. Therefore, when the switches l-S and IS' stop in their third off-normalpositions due to the opening of the select key SK--3, the relay H3 becomes deenergized as soon as relay C opens its contacts because the locking circuit of relay H--3 is open at the contacts of select key SK-3. Therefore, there is no intermittent operation of the lamp LW--3 in response to the manual operation of the apparatus unit A'U-3 by the dispatcher.

In Fig. 2 of the accompanying drawings I have shown my invention in connection with a code selector supervisory system of the particular type disclosed in United States Letters Patent 2,205,894, granted June 25, 1940, and assigned to the assignee of this application, but it will be obvious that my invention is not limited to this particular type of code selector supervisory system. In order to simplify the disclosure in the present application, only that portion of the supervisory system disclosed in the aforesaid patcut is illustratedin detail in Fig. 2 as is deemed necessary for a complete understanding of the present invention.

In Fig. 2 the supervisory system includes two conductors L-l and L-Z extending between a dispatchers offi-ce DO and a remote station RS. At the dispatchers oflice a group of control keys and indicating lamps is provided for each apparatus unit to be selected and controlled at the remote station. Only one such group of keys and lamps is shown in Fig. 2, and this includes a two-positionselect key SK-3, which is operated by the dispatcher when he wants to select the-corresponding apparatus unit AU3 at the remote station for operation and a two-position disagreement key DK--3 which controls the operation of the corresponding indicating lamps. The apparatus unit A'U'-3 is shown as an automatic reclosed circuit breakerwhich is similar in construction and operation to the circuit breaker A'U--3 shown in Fig. 1.

The illustrated group of lamps includes a red lamp LR-3, which, when lighted, indicates that the corresponding apparatus unit A'U'--3 is in one position, such as its closed position; a green lamp LG--3, which, when lighted, indicates that the corresponding apparatus unit AU3 is in another position, such as its open position; and a white lamp LW-3, which, when continuously lighted, indicates that the position of the corresponding apparatus unit A'U--3 does not correspend with the position of th associated disagreement key DK-3. Each group of keys and lamps has associated therewith an individual in dicating relay, such as IR-3, which determines by its position whether the associated red or green lamp is lighted and which cooperates with the associated disagreement key DK3 so as to determine whether the associated white lamp LW--3 is lighted. The position of the indicating relay IR-3 is determined by the position of the corresponding apparatus unit A'U'--3 at the re-' mote station.

As disclosed in detail in the aforesaid Letters Patent 2,205,894, when the dispatcher desires to select the apparatus unit A'U'-3 at the remote station RS, he operates the corresponding select key SK--3 at the dispatchers ofiice, and this effects the operation of various devices at the dispatchers office including two finder switches l-F and i2--F which are operated to positions corresponding to the operated select key SK3.

The positions in which the finder switches l-F and 2F stop determine the select code. As soon as the finder switches l-F and 2--F stop in the positions corresponding to the operated select key SK-3, the operation of a code finder l-S is initiated to transmit over the two line conductors L-l and L-Z the code.of impulses which has been set up by the operated finder switch I F.

The finder switches IF and 2F and the code sender l--S are shown as being selector switches of the well known rotary type comprising a plurality of banks of contacts, each bank having as-- sociated therewith a cooperating wiper and means for simultaneously operating all of the wipers in a step by step movement. Only those banks of contacts are shown in Fig. 2 as are necessary for a clear understanding of the present invention. Consequently, I have shown only the banks I-FB of the finder switch l-F, the banks 2-F3 and 2-F5 of the finder switch 2-F and the banks l-S4 and l-S5 of the code sender I-S.

At the remote station RS the code of im ulses, which is transmitted over the line conductors L-l and L-Z, selectively controls a receiver R so as to select the apparatus unit AU-3. At the termination of the transmission of theselect code, two finder switches l-F' and 2-F' at the remote station are operated to positions corresponding to the apparatus unit selected by the receiver R. As soon as the finder switches l-F and 2F, which are similar in construction to the finder switches l-F and 2-F at the dispatchers o fiice, have reached the positions corresponding to the selected apparatus unit, a code sender I-S, at the remote station RS and similar in construction to the code sender 'l-S, is started to effect the transmission to the dispatchers oiiice over the line'conductors Ll and L-2, a check code of current impulses, which depends upon the positions of the finder switches I-F' and 2-F'. This check code of impulses is followed by either a positive or a negative indiwith indicate the position then occupied by the.

selected apparatus unit. Also the necessary circuit connections are established at the dispatchers office so that the dispatcher canoperate the selected apparatus unit as many times as he desires and can release the connectionwhenever he so desires.

when the supervisory equipment is at rest and an apparatus unit at the remote station changes its position, the associated indicating relay, such as I'A'-3 associated with the apparatus unit A'U'-3, is deenergized and causes the finder switches l--F and 2F' to move to the positions thereof corresponding to the apparatus unit which has changed its position. Then the code sender IS" operates to transmit select code of current impulses corresponding to the apparatus unit which has changed its position. This select code, however, is not immediately followed by an indicating impulse corresponding to the new position of the apparatus unit which has changed its position.

At the dispatchers oflice this select code operates the receiver R so as to select the group of indicating lamps and associated relays corresponding to the apparatus unit which has changed its position. At the termination of the transmission of the select code the two finder switches IF and 2-F at the dispatchers offlce are operated to the positions thereof corresponding to the group of indicating lamps and relays selected by the receiver R. As soon as the finder switches I--F and 2F have reached the positions corresponding to the selected group of indicating lamps and relays, the code sender I--S operates to transmit to the remote station RS over the line conductors Ll and L2 a check code of impulses corresponding to the selected group of indicating lamps and relays.

At the remote station the check code of impulses selectively controls the receiver R. If

the select and check codes agree, the receiver R l effects, after the termination of the check code, the transmission over the line conductors L-l and L-2 of an indicating impulse of a polarity corresponding to the position of the apparatus unit which has changed its position. At the dispatchers ofiice this indicating impulse selectively operates the selected group of lampsso as to indicate the position of the apparatus unit which has changed its position. As soon as the indication impulse has been transmitted, the selective apparatus automatically resets to normal.

As disclosed in detail in the aforesaid Letters Patent 2,205,894, there is provided at the dispatchers oflice (DO) a relay N-3, which is energized only when the code sender I-S is in its normal position; a relay S-I, which operates after the finder switch l-F has stopped in any of its normal positions; and a relay -3, which is energized in case the receiver R receives a code of impulses before the code sender l-S is operated to transmit a code of impulses, namely, only in case the operation of the supervisory equipment is initiated in response to one of the apparatus units at the remote station RS changing its position.

In the arrangement disclosed in the aforesaid patent, it an apparatus unit should move from its normal position to its oil-normal position and then be restored to its normal position before the supervisory equipment has completed the connection to the corresponding indicating means at the dispatchers oflice, the indicating impulse, which is transmitted after the connection has been established, will be of the polarity corresponding to the normal position of the apparatus unit. Consequently, there will be no change in the lighting of the corresponding red, green or white lamps at the dispatchers oflice.

In order to obtain a permanent indication of such a change in the position of an apparatus unit, I provide each group of indicating lamps in Fig. 2 with a separate relay, which is arranged to be energized in response to the finder switch IF being moved to the position thereof allotted to the associated indicating means as a result of the corresponding apparatus unit changing its position. This is accomplished in the embodiment of my invention, shown in Fig. 2, by completing the circuit of each separate relay, such as relay H3 corresponding to the apparatus unit AU-3, through the contacts 9 of relay 0-3 and contacts e of relay Sl after the finder switch has stopped in the position thereof allotted to apparatus unit AU'3. Since relay C-3 is energized only in case the receiver R receives the code before the sender I-S transmits the code, relay H3 is energized only in case the establishment of the connection between the apparatus unit AU--3 and its corresponding group of indicating lamps and relays is initiated in response to the apparatus unit AU"3 changing its position. By closing its contacts 24, relay H3, when energized, completes a locking circuit for itself through contacts 26 of the disagreement key DK-3 if it is in its position corresponding to the closed position of the apparatus unit A'U3 and contacts 21 of the indicating relay IR-3 if it is in its position corresponding to the closed position of the apparatus unit A'U'3. Relay H3, therefore, is operated before the indicating impulse is transmitted.

If, when the apparatus unit A'U'-3 is opened, it remains in its open position long enough to allow an indicating impulse corresponding to the open position of the apparatus unit to be transmitted while the relay H3 is energized then indicating relay 1R-3 is moved to its other position and the locking circuit of the relay H3 is opened so that, as soon as the supervisory apparatus is reset to normal after the indicating impulse is transmitted, the relay H3 becomes deenergized.

When the code sender IS is restored to its normal position after the indicating impulse is transmitted, a circuit is completed through the normal contacts of bank 1-84 at the dispatchers office for the control relay N3. If the relay H3 is energized when the relay N3 becomes energized, a circuit is completed for relay F which in turn completes a flashing circuit for the white lamp LW3 through an interrupter IR so that the lamp LW-3 is intermittently lighted at the same time that the red lamp LR3 is continuously lighted. This combination of lighted lamps informs the dispatcher that the apparatus unit A'U'--3 has opened and reclosed. The dispatcher can then extinguish the flashing white lamp LW--3 by operating the disagreement key 7 DKE-3 in the same manner it is operated in order to extinguish a flashing white lamp in the arrangement disclosed in Fig. 1.

The operation of the arrangement shown in Fig. 2 is as follows:

When. the selective means is at rest and the 1 apparatus unit A'U'-3 is closed, the various control devices of the supervisory equipment occupy the positions in which they are shown in. the drawings. At the dispatchers office an energizing circuit for relay N-.3 is completed through the normal contact of bank IS4. Acircuit is completed for the red lamp LR- -3 through the contacts 30 of the indicating relay IR-3 so that this lamp is .continuously lighted and thereby informs the dispatcher that the apparatus unit A'U- 3 at the remote station is closed. At the remote station the indicating. relay IA-3 is energized by-a locking circuit which includes contacts ill of the relay IA--3 and the auxiliary contacts I! of the closed apparatus unit AU'-3.

It will be assumed first that the selector switch SK3 is moved to its off-normal position so as to cause the supervisory equipment to operate in a well known manner to establish a connection between the apparatus unit A'U'--3 at the remote station RS and its corresponding indicating means at the clispatchers oflice after which an indicating impulse corresponding to the position then occupied by the apparatus unit 'A'U'-3 is transmitted over the line conductors Ir-l and L-Z to the indicating relay IR-3. If the apparatus unit AU'-3 is still in its closed position after the connection is established, the indicating impulse is of such a character that the relay Hit-3 remains in the position in which it is shown so that the lamp LR--3 remains continuously lighted. If the apparatus unit AU'3 is in its'open position when the connection is established, the indicating impulse is of such a character that the relay IR-3 is moved to its other position, so that the red lamp LR-3 is extinguished as the circuit of the green lamp LG--3 is completed at the contacts 34 of the relay 13-3. Also a circuit is completed for the white lamp LW-3 through the contacts 34 of the relay IR--3, the contacts 36 of the disagreement key DK-3 and the contacts 35 of the relay H-3. By moving the disagreement key ,DK--3 to the position thereof corresponding to the open position of the apparatus unit AU-3, the continuous lighting of the white lamp. LW-3 is discontinued. The selection may be released at any time by restoring the select key SK-3 to its normal position.

It will now be assumed that, While the supervisory equipment is at rest, the apparatus unit A'U'--3 automatically opens so that its contacts I! interrupt the holding circuit for the associated indicating relay I'A'-3. The deenergization of the indicating relay IA-3 then effects 'in a well known manner the establishment of a connection between the apparatus unit A'U'3 and its corresponding group of indicating lamps and relays at the dispatchers oflice after which an indicating impulse corresponding to the position of the apparatus unit AU-3 is transmitted over the line conductors Ll and L-Z to the indicating relay IR.3. Since the receiver R receives code before the code sender l--S transmits code, the relay H3.is energized in the manner heretofore described before the indicating imdisagreement key DK-3.

pulse is" transmitted to the indicating relay IR-3.

If the apparatus unit AU-3 is'in its open position at the time the indicating impulse is transmitted, this indicating impulse is of such a character that} the indicating relay IR-'-3 moves to its other position so that the contacts 21 andv 30 are opened and the contacts 34 are closed. The opening of the contacts 21 interrupts the heretofore described locking circuit of the relay H. -3 so that this relay becomes deenergized as soon as the connection is released after the indicating impulse is transmitted. The opening of the contacts 30 of the relay IR--3 extinguishes the red lamp Lit-3, and the closing of the contacts 34 completes a circuit for the green lamp LG3 and a circuit for the white lamp LW--3 through contacts 35 of relay H-3 when it is in its deenergized position and contacts 36 of the The continuous lighting of the lamps LG--3 and LW-3 informs the dispatcher that the apparatus unit A'U'--3 has opened and is still in its open position. By moving the disagreement key DK--3 to its other position, which corresponds to the open position of the apparatus unit A'U--3, the circuit of the white lamp LW-3 is opened so that only the green lamp LG-3 remains lighted,

It will now be assumed that, after the apparatus unit A'U'3 opens, it is immediately reclosed and is in its closed position when the indicating impulse is transmitted. Under these conditions, the character of the indicating impulse is such that it does not change the position of the indicating relay IR-3. Consequently, the red lamp LR-3 remains lighted and the locking circuit of the relay H--3 remains completed after the supervisory apparatus has been restored to its normal condition. When the relay N-3 becomes energized by the finder IF being restored to its normal position, theclosing of its contacts 31 completes, through contacts 38 of relay 1-1-3, an energizing circuit for relay F. The closing of contacts 39 of relay F completes a locking circuit for relay F around the contacts 31 of relay N-3, and the closing of contacts 40 of relay F completes a flashing circuit for white lamp LW--3 through contacts 4| of relay H-3 and interrupter IR. The continuous lighting of the lamp LEI-3 and the flashing of lamp LW-'3 at the same time informs the dispatcher that the apparatus unit A'U'3 has automatically opened and reclosed and is still in its closed position. By moving the disagreement key DK-3 to its other position and then back to the position in which it is shown, the dispatcher can extinguish the lamp LW-3 so that only the red lamp LR,3 remains lighted.

While I have, in accordance with the patent sta utes, shown and described my invention as applied to a narficua sustrm and as e bodying various devices diagrammatically indicated, changes and modifications will be obvious to those skilled in the art, and I therefore aim in'the appended cla ms to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a supervisory system in which selective means at two points are adapted to be operated to establish connections respectively between a plurality of movable devices at one of said points and corresponding indicating means at the other point, means responsive to any of said devices which device has changed its position and whether at the time such an impulse is transmitted that device is in a different position than the position from which it moved to initiate theoperation of said selective means or is in the position from which it moved to initiate the operation of said selective means.

2. In a supervisory system in which selective means at two points are adapted to be operated to establish connections respectively between a plurality of movable devices at one of said points and corresponding indicating means at the other point, means responsive to any of said devices changing its position for initiating the operation of said selective means so as to establish a connection between the device initiating the operation of said selective means and the corresponding indicating means and for transmitting between said points while said connection is established an indicating impulse of a character dependent upon the position then occupied by such device, and means for operating the indicating means corresponding to the device which initiated the operation of said selective means so as to indicate which device has changed its position and whether or not it has been restored to its original position at the time'said impulse is transmitted including means dependent upon the character of said impulse for operating the indicating means in one manner when said current impulse is transmitted as a result of said device being in a different position than the position from which it moved to initiate the operation of said selective means and in a difierent manner when said current impulse is transmitted as a result of said device being in the same position from which it moved to initiate the operation of said selective means.

3. In a supervisory system in which selective means at two points are adapted to be operated to establish connections respectively between a plurality of movable devices at one of said points and corresponding indicating means at the other point, means responsive to any of said devices changing its position for initiating the operation of said selective means so as to establish a connection between the device initiating the operation of said selective means and the corresponding indicating means and for transmitting be tween said points while said connection is established an indicating impulse of a character dependent upon the position then occupied by such device, and means for operating the indicating means corresponding to the device which initiated the operation of said selective means so as to indicate which device has changed its position and whether or not it has been restored to its original position at the time said impulse is transmitted including means dependent upon the character of said impulse for operating the indicating means continuously when said current impulse is transmitted as a result of said device being in a difierent position than the position from which it moved to initiate the operation of said selective means and intermittently when said current impulse is transmitted as a result of said device being in the same position from which it moved to initiate the operation of said selective means.

4. In a supervisory system in which selective means at two points are adapted to'be operated to establish connections respectively between a plurality of two-position devices at one of said points and corresponding normally nonoperating indicating means at the other point, means responsive to any of said devices moving from one of its positions to another for initiating the operation of said selective means so as to establish a connection between the device initiating the operation of said selective means and the corresponding indicating means and for transmitting between said points when such connection is established an indicating impulse of a character dependent upon the position then occupied by such device, a disagreement key at said other point individual to each device at said one point and having two positions corresponding respectively to the two positions of the associated device, and means for operating the indicating means corresponding to the device that initiated the operation of said selective means so as to indicate which device has changed its position and whether or not it has been restored to its original position at the time said impulse is transmitted including means dependent upon the character of said current impulse and the position of the associated disagreement key for operating the corresponding indicating means in one manner when said device is in said other position to which it has been moved and in a different manner when it has been restored to said one position at the time said impulse is transmitted.

5. In a supervisory system in which selective means at two points are adapted to be operated to establish connections respectively between a plurality of two-position devices at one of said points and corresponding indicating means at the other point, means responsive to any of said devices moving from one of its positions to another for initiating the operation of said selective means so as to establish a connection between the device initiating the operation of said selectlve means and the corresponding indicating means and for transmitting between said points when such connection is established an indicating impulse of a character dependent upon the position then occupied by such device, a disagreement key at said other point individual to each device at said one point and having two positions corresponding respectively to the two positions of the associated device, and means for operating the indicating means corresponding to the device-that initiated the operation of said selective means so as to indicate which device has changed its position and whether or not it has been restored to its original position at the time said impulse is transmitted including means dependent upon the character of said current impulse and the position of the associated disagreement key for operating the corresponding indicating means in one manner when said disagreement key is in a predetermined position and said impulse is of a predetermined character and in a difierent manner when said disagreement key is in said other position and said impulse is of said predetermined character.

6. In a supervisory system in which selective means at two points are adapted to be operated ated position.-

to establish a connection betweena predetermined twoposition device at-one' otsaid points and corraponding indicating means at the other point and in which an indicating impulse of current of a character dependent uponthe position occupied by said device is transmitted between said points while said connection is established, means dependentupon the movement of said device from one position to another for device, a control relay, means dependent upon *9 manually ontrdlledfmealns and: intermittently in response to thetransmissionoi an indicating impulse or said predetermined character when said.

connection is established as a result of said device changing its position.

9. In a'supervisory system in which selective means at two stations are adapted to beeper-ated to establish a connection between an apparatus unit having a normalposition and an oft-normal position at one of said stations and indicating a means at the other; station comprising an indithe establishment'ot said connection being inlti-' ated by the movement of said device from one position to another ioreilfecting the operation of said control relay, means dependent upon the character ofsaid impulse and the position of said disagreement key for maintaining said relay in its operated condition, and means for operating said indicating means in one manner when said relay is in its normal position and in a diilerent manner when said relay is in its opera 7. In a supervisory system in which selective means at two points are adapted to be operated to establish a connection between a predeter mined movable device at one of said points and corresponding indicating means at the other point and in which an indicating impulse of current of a character dependent upon the position. occupied bysaid device is transmitted between said points while said connection is established,

means dependent upon the movement of said deand means at said other point for controlling,

said indicating means in one manner in response to the transmission of an indicating impulse of a predetermined character when said connection is established asa result of an operation of said manually controlled means and in a different m-annerin'res'ponse to the transmission oi. an indicating impulse of saidpredetermined character when said connection is established as a result of said device changing its position.

8. In a supervisory system in which selective means at two points are adapted to be operated to establish a connection betweena predetermined movable device at one of said points and corresponding indicating means at the other point. and in which an indicating impulse of current of a character dependent upon the position occupied by said deviceis transmittedbetween said points while said connection is established,

means dependent upon the movement of said device'from one position to another for initiating the operation of said selective means to establish said connection andthe transmission of said indicating impulse, manually controlled means at said other point for initiating the operationot said selective means to establish said connection and the tr nsmission of said indicating impulse, and means at said other point for operating said indicating means continuously in response to the transmission of an indicating impulse of a predetermined character'when said connection is established as a. result of an operati n oi said cating 'lamp for each position of said unit and a disagreement lamp and in which an indicating impulse of current of a character dependent upon the position occupied by said unit is transmitted between said stations while said connection is established, a disagreement key associated with said indicating means and having positions corresponding to the positions of said unit, means dependent upon said unit moving from either of its positions to the other for initiating the operation of said selective means to establish said connection; and the transmission of said indicating impulse, and means at said other station controlled by said impulse for selectively operating said indicating lamps in accordance with the character of said impulse and for operating said disagreement lamp continuously if said unit is in its ofi-normalposition and said disagreement key is in its position corresponding to the normal position of said unitwhen said impulse is transmitted and for operating said disagreement lamp intermittently it said unit is in its normal position and said disagreement key is in its position corresponding to the normal position of said unit when said impulse is transmitted as a result of the establishment of said connection being initiated by said unit changing its position.

10. In a supervisory system in which selective means at two stations are adapted to be operated to establish a connection between an apparatus unit having a normal position and an oft-normal position at one of said stations and indicating means at the other station comprising an indicating lamp for each position of said unit and a disagreement key and in which an indicating impulse of current of a character dependent upon the position occupied by said unit is transmitted between said stations while said connection is established, a disagreement key associated with said indicating means and having positions cortion of said selective means to establish said connection and the transmission of said indicating impulse, and means at said other station controlled by said impulse for selectively operating said indicating lamps in accordance with the character of said impulse and means at said other stationcontrolled by the position of said disagreement key and the character 01 said impulse for lighting said'disagreement lamp in diiferent ways.

11. In a supervisory system in which selective means at two stations are adapted to be operated to establish a connection between an apparatus unit having a normal position and an oil-normal position at one of said stations and indicating means at the other station comprising an indicating lamp for each position of said unit and a disagreement key and in which an indicating impulse of currentof a character dependent upon the position occupied by said unit is transmitted e w en said stations while said connection is established, a disagreement key associated with said indicating means and having positions corresponding to the positions of said unit, meansdependent upon said unit moving from either of its positions to the other for initiating the operation of said selective means to establish said connection and the transmission of said indicating impulse, control means at said other station for initiating the operation of said selective means to establish said connection and the transmission of said indicating impulse, a control relay at said other station, means for eiiecting the operation of said control relay only upon the establishment of said connection being initiated by the movement of said unit from one position to another, means at said other station controlled by said impulse for selectively operating said indicating lamps in accordance with the character 01 said impulse, and means dependent upon the position of said disagreement key and the condition of said relay for operating said disagreement lamp in diii'erent ways in r ponse to the transmission 01- an impulse of a. predetermined character.

1'2. In a supervisory system in which selective means at two stations are adapted to be operated to establish a connection between an apparatus unit having a normal position and an oil-normal position at one oi said stations and indicating means at the other station comprising an indicating lamp for each position of said unit and a disagreement key and in which an indicating impulse 01 current oi a character dependent upon the position occupied by said unit is transmitted between said stations while said connection is established, a disagreement key associated with said indicating means and having positions corresponding to the positions of said unit, means dependent upon said unit moving from either 01' its positions to the other for initiating the operation of said selective means to establish said connection and the transmission of said indicating impulse, control means at said other station for initiating the operation of said selective means to establish said connection and the transmission of said indicating impulse, a control relay at said other station, means for eil'ecting the operation of said control relay only upon the establishment of said connection being initiated by the movement of said unit from one position to another, means at said other station controlled by said impulse for selectively operating said indicating lamps in accordance with the character oi! said impulse, and means for operating said disagreement lamp continuously when said relay is in its normal position and said disagreement key is in its position corresponding to the normal position of said unit and the indicating impulse is of the character corresponding to the normal position of said unit and for operating said disagreement lamp intermittently when said relay is in its operated position and said disagreement key is in its position corresponding to the normal position of said unit and the indication impulse is of the character corresponding to the normal position oi said unit.

13. In a synchronous selector supervisory system in which multiple position switches at two points are synchronously operated and in which means are provided whereby when said switches are simultaneously in predetermined positions corresponding to a predetermined movable device at one of said points an indicating impulse oi current of a character dependent upon the position occupied by said device is transmitted between said points, means dependent upon the movement oi said device for causing said switches to remain in said predetermined positions corresponding to said device during the synchronous operation of said switches for one length of time it said device has not changed its position since the previous indicating impulse for said device was transmitted and for a diflerent length of time it said device has changed its position since the previous indicating impulse for said device was transmitted, and means at the other of said points dependent upon the character or said impulse and the length of time said switches remain in sai predetermined positions corresponding to said device for indicating whether said device has been operated so that it is in a different position than the position it was in when the previous indicating impulse for said device was transmitted or said device has been operated so that it has been restored to the same position it was in when the previous indicating impulse for said device was transmitted.

14; In a synchronous selector supervisory system in which multiple position switches at two points are synchronously operated and in which means are provided whereby when said switches are simultaneously in predetermined positions corresponding to a predetermined movable device at one of said points an indicating impulse of current of a character dependent upon the position occupied by said device is transmitted between said points, means dependent upon the movement of said device for causing said switches to remain in said predetermined positions corresponding to said device-during the synchronous operation of said switches for one length of time if said device has not changed its position since the previous indicating impulse for said device was transmitted and for a diflerent length oi time ii. said device has changed its position since the previous indicating impulse for said device was transmitted, signalling means at the other of said points, and means dependent upon the character of said current impulse and the length of time said switches remain in said predetermined positions corresponding to said device for operating said signalling means in one manner when said current impulse is transmitted as a result of said device being in a different position than the position it was in when the previous indicating impulse for said device was transmitted and in a different manner when said current impulse is transmitted as a result 01' said device being. operated in such a way that it has been restored to the same position it was in when the previous indicating impulse for said device was transmitted.

15. In a synchronous selector supervisory system in which multiple position switches at two points are synchronously operated and in which means are provided whereby when said switches are simultaneously in predetermined positions corresponding to a predetermined movable device at one of said points an indicating impulse of current of a character dependent upon the position occupied by said device is transmitted between said points, means dependent upon the movement of said device for causing said switches to remain in said predetermined positions corresponding to said device during the synchronous operation of said switches for one length of time if said device has not changed its position since the previous indicating impulse for said device was transmitted and for a diflerent length of time if said device has changed its position since the previous indicating impulse for said device was transmitted, signalling means at the other of said points, and means dependent upon the character of said current impulse and the length of time said switches remain in said predetermined positions corresponding to said device for operating said signalling means continuously when said current impulse is transmitted while said device is in a different position than the position it was in when the previous current impulses for said device was transmitted and intermittently when said current impulse is transmitted as a result of said device being operated in such a manner that it has been restored to the' same position it was in when the previous current impulse for said device was transmitted.

16. In a synchronous selector supervisory system in which multiple position switches at two points are synchronously operated and in which means are provided whereby when said switches are simultaneously in predetermined positions a current impulse of one polarity is transmitted between said points if a predetermined two-position device is in a predetermined one of its positions and a current impulse of the opposite polarity is transmitted between said points if said device is in its other position, means for causing said switches during synchronous operation thereof to remain in said predetermined positions for one length of time if said device has not changed its position since the previous indicating impulse for said device was transmitted and for a longer length of time if said device has changed ent position than the position it was in when the previous current impulse for said device was transmitted or said device has been operated so that it has been restored to the same position it was in when the previous current impulse for said device was transmitted.

17. In a synchronous selector supervisory'systerm in which multiple position switches at two points are synchronously operated and in which means are provided whereby when said switches are simultaneously in predetermined positions 7 a current impulse of one polarity is transmitted between said points if a predetermined two-position device is in a predetermined one of its positions and a current impulse of the opposite polarity is transmitted between said points if said device is in its other position, means for causing said switches during synchronous operation thereof to remain in said predetermined positions for one length of time if said device has not changed its position since the previous inl dicating impulse for said device was transmitted and for a longer length of time if said device has changed its position since the previous inmined polarities and said switches remain in said predetermined positions for said longer length of time and for operating said signal intermittently when said indicating impulse is of the otherpolarity and said switches remain in said predetermined positions for said longer length of time. a

18. In a synchronous selector supervisory sys-- term in which multiple position switches at two points are synchronously operated and in which means are provided whereby when said switches are simultaneously in predetermined positions a current impulse of one polarity is transmitted between sad points if a predetermined two-position device is in a predetermined one of its positions and a current impulse of the opposite polarity is transmitted between said points if said device is in its other position, means for causing said switches during synchronous operation thereof to remain in said predetermined positions for one length of time if said device has not changed its position since the previous indicating impulse for said device was transmitted,

a non-operating signal at said other point, and means dependent upon the polarity of said indicating impulse and the length of time said switches remain in said predetermined positions for operating said signal continuously when said indicating impulse is of one of said predeterdicating impulse for said device was transmitted and for a longer length of time if said device has changed its position since the previous indicating impulse for said device was transmitted, a non-operating signal at said other points, means dependent upon the polarity of said indicating impulse and the length of time said switches remain in said predetermined positions for operating said signal continuously when said indicating impulse is of one ofsaid predetermined polarities and said switches remain in said predetermined positions for said longer length P of time and for operating said signal intermittently when said indicating impulse is of the other polarity and said switches remain in said predetermined positions for said longer length of time,'and means at said other point for restoring said signal to its non-operating condition after it has been operated.

19. In a synchronous selector supervisory system in which normally idle multiple position selector switches are provided at two points and which means areprovided whereby when said switches are simultaneously in predetermined corresponding positions an indicating impulse of current of a character dependent upon the position occupied by a two-position device at one of said points is transmitted to the other of said two points, means for synchronously operating said switches through their corresponding positions, means for causing said switches to stop in said predetermined corresponding positions for a longer time when said device has changed its position than when it has not changed its position since the last time said switches were in said predetermined corresponding positions, a signal at the other of said points, a disagreement key at said other point having two positions corresponding respectively to the two positions of said device, a control relay, means responsive to said switches stopping in said predetermined corresponding positions for said longer time for effecting the operation of said control relay, means dependent upon the char acter of the indicating impulse transmitted while said switches are in said predetermined corresponding positions and upon the position of said disagreement key for maintaining said relay in its operated condition, and means for operating said signal in one manner when said relay is in its normal condition and in a different manner when said relay is in its operated condition.

20. In a synchronous selector supervisory system in which normally idle multiple position selector switches are provided at two points and in which means are provided whereby when said switches are simultaneously in-predetermined corresponding positions an indicating impulse of current of a character dependent upon the position occupied by a two-position device at one of said points is transmitted to the other of said two points, means for synchronously operating said switches through their corresponding positions, means for causing said switches to stop in said predetermined corresponding positions for a longer time when said device has changed its position than when it has not changed its position since the'last time said switches were in said predetermined corresponding positions, a signal at the other of said points, a disagreement key at said other point having two positions corresponding respectively to the two positions of said device, a control relay, means responsive to said switches stopping in said predetermined corresponding positions for said longer time for effecting the operation of said control relay, means dependent upon the character of the indicating impulse transmitted while said switches are in said predetermined corresponding positions and upon the position of said disagreement key for maintaining said relay in its operated condition, and means for operating said signal in one manner when said relay is in its normal condition and in a different manner when said relay is in its operated condition and said switches are restored to their idle positions.

21. In a synchronous selector supervisory system in which normally idle multiple position selector switches are provided at two points and in which means are provided whereby when said switches are simultaneously in predetermined corresponding positions an indicating impulse of current of a character dependent upon the position occupied by a two-position device at one of said points is transmitted to the other of said two points, means for synchronously operating said switches through their corresponding positions, means for causing said switches to stop in said predetermined corresponding positions for a longer time when said device has changed its position than when it has not changed its position since the last time said switches were in said predetermined corresponding positions, a signal at the other of said points, a disagreement key having two positions corresponding respectively to the two positions of said device, a normally deenergized relay, means responsive to said switches stopping in said predetermined corresponding positions for said longer time for effecting the energization of said relay, means dependent upon the character of the indicating impulse transmitted while said switches are in said predetermined corresponding positions and upon the position of said disagreement key for completing a locking circuit for said relay, and means controlled by said relay for operating said signal continuously when the said relay is deenergized and the position of said disagreement key does not agree with the position of said device and for operating said signal intermittently when said relay is energized and the position of said disagreement key agrees with the positionof said device.

22. In combination, a dispatchers ofiice, a remote station, a normally closed circuit breaker at said remote station, means for opening said circuit breaker, automatic means for reclosing said relay associated with said circuit breaker, means responsive to an opening of said circuit breaker for deenergizing said relay, indicating'means at said dispatchers ofilce for indicating the position of said circuit breaker, a selector switch at each station having a normal position and a predetermined off-normal position individual to said circuit breaker, means for transmitting between said stations an indicating impulse of a character dependent upon the position of said circuit breaker when both of said switches are simultaneously in said predetermined oil-normal positions, means for controlling said indicating means in response to the character of said indicating impulse and the length of time said switches remain in said predetermined ofi-normal positions, means independent of the length of said impulses for operating said switches in synchronism including means for initiating said synchronous operation in response to the deenergization of said relay, means controlled by said relay for'stopping said synchronous operation when said switches are in said predetermined offcircuit breaker, a normally energized indicating normal positions and said relay is deenergized and for immediately continuing said synchronous operation when said switches are in said predetermined oil-normal positions and said relay is energized, and means responsive to said switches remaining in said predetermined oil-normal positions for a predetermined time when said relay is deenergized for initiating the synchronous operation of said switches.

23. In combination, a dispatchers oflice, a remote station, a normally closed circuit breaker at said remote station, means for opening said circuit breaker, automatic means for reclosing said circuit breaker, a normally energized indicating relay associated with said circuit breaker, means responsive to an opening of said circuit breaker for deenergizing said relay, indicating means at said dispatchers oflice for indicating the position of said circuit breaker, a selector switch at each station having a normal position and a predetermined off-normal position individual to said circuit breaker, means for transmitting between said stations an indicating impulse of a character dependent upon the position of said circuit breaker when both of said switches are simultaneously in said predetermined 011- normal positions, means for controlling said indicating means in response to the character of said indicating impulse and the length of time said switches remain in said predetermined 01T- normal positions, means independent of the length of said impulses for operating said switches in synchronism including means for initiating said synchronous operation in response to the deenergization of said relay, means controlled by said relay for stopping said synchronous operation when said switches are in said predetermined ofi-normal positions and said relay is deenergized and for immediately continuing said synchronous operation when said switches are in said predetermined off-normal positions and said relay is energized, and means responsive to said switches remaining in said predetermined offnormal positions for a predetermined time when said relay is deenergized for initiating the synchronous operation of said switches and the energization of said relay,

24. In combination, two stations, an apparatus unit at one of said stations having a plurality of positions, a normally energized relay associated with said unit, means responsive to a change in the position 01 Said unit for deenergizing said relay, indicating means at the other of said stations for indicating the position ofsaid unit,

a multiple position switch at each station having a predetermined position individual to said unit, means for transmitting between said stations a current impulse of a character dependent upon the position of said unit when both of said switches are simultaneously in said predetermined positions, means independent of the length of said impulses and responsive to the deenergization of said relay for operating said switches to said predetermined positions, means controlled by said relay for effecting the movement of said switches out of said predetermined positions immediately when said relay is energized and after a predetermined time interval when said relay is deenergized, and means at said other station for controlling the operation of said signalling means in response to the character of said imp ilse and the length of time said switches remain in said predetermined positions.

25. In combination, two stations, an apparatus unit at one of said stations having a plurality of positions, a normally energized relay associated with said unit, means responsive to a change in the position of said unit for deenergizing said relay, indicating means at the other of said stations for indicating the position of said unit, a multiple position switch at each station having a predetermined position individual to said unit, means for transmitting between said stations a current impulse of-a character dependent upon the position of said unit when both of said switches are simultaneously in said predeter mined positions, means for operating said switches to said predetermined positions, means responsive to the deenergization of said relay for initiating the operation of said operating means, manually controlled means at said other station for initiating the operation of said' operating means, and means at said other station for controlling said indicating means inone manner in response to the transmission of an impulse of a predetermined character when said switches are in said predetermined positions as a result of an operation of said manually controlled means and in a different manner in response to the transmission of an impulse of said predetermined character when said switches are in said predetermined positions as a result of a deenergization of said relay.

26. In combination, two stations, an, apparatus unit at one of said stations having a normal position and an oil-normal position, means for moving said unit-from each position to the other, a normally energized relay associated with said unit, means responsive to a change in the position of said unit while said relay is energized for deenergizing said relay, indicating means at the other of said stations for indicating the position of saidunit, a multiple position switch at each station having a predetermined position individual to said unit, means for transmitting between said stations a current impulse of a character dependent upon the position of said unit when both of said switches are simultaneously in said predetermined positions, means for operating said switches to said predetermined positions, means responsive to the deenergization of said relay for initiating the operation of said operating means, control means at said otherstation for initiating the operation of said operating means, and means at saidotherstation for controlling said indicating means in response to the character of said impulse including means for sitions as a result of an operation of said control means and said unit is in its normal position when said switches are in said predetermined positions.

2'7. In combination, two stations, an apparatus unit at one of said stations having a normal position and an ofi-normal position, means for moving said unit from, each position to the other, a normally energified relay associated with said unit, means responsive to a change in the position of said unit while said relay is energized for deenergizing said relay, indicating means at the other of said stations for indicating the position of said unit, a multiple position switch at each station having a predetermined position individual to said unit, means for transmitting between said stations a current impulse of a character dep'endentupon the position of said unit when both of said switches are simultaneously in said predetermined positions, means for operating said switches to said predetermined positions, means responsive to the deenergization of said relay for initiating the operation of said operating means, and means at'said other station controlled by said impulse for operating said indicating means continuously, if said unit is in its off-normal position when said switches reach said predetermined positions in response to the deenergization of said relay and intermittently if said unit is in its normal position when said switches reach said predetermined positions in response to the deenergization of said relay.

28. In combination, two stations, an apparatus unit at one of said stations having a normal position and an off-normal position, means for moving said unit from eachposition to the other, a normally energized relay associated with said unit, means responsive to a change in the position of said unit while said relay is energized for deenergizing said relay, indicating means at the other of said stations for indicating the position of said unit, saidindicating means including an indicating lamp for each position of the unit and a disagreement lamp, a disagreement key associatedwith said indicating means and having positions corresponding to the positions of said unit, a multiple position switch at each station having a predetermined position individual to said unit,

means for transmitting between said stations a current impulse of a character dependent upon the position of said unit when both of said switches are simultaneously in said predetermined positions, means for operating said switches to said predetermined positions, means responsive to the deenergization of said relay for initiating the operation of said operating means, and means at said other station controlled by said impulse for selectively operating said indicating lamps in accordance with the character of saidimpulse and for operating said disagreement lamp continuously if said unit is in its off-normal position and said disagreement key is in its position corresponding to the normal position of said unit when said switches reach said predetermined positions in response to the deenergization of said relay and for operating said disagreement lamp intermittently if said unit is in its normal position and said disagreement key is in its position corresponding to the normal position of said unit when said switches reach ,said predetermined positions in response to the deenergization of said relay.

29. In combination, two stations, an apparatus unit at one of said stations having a normal position and an oiT-normal position, means for moving said unit from each position to the other, a normally energized relay associated with said unit, means responsive to a change in the position of said unit while said relay is energized for deenergizing said relay, indicating means at the other of said stations for indicating the position of said unit, said indicating means including an indicating lamp for each position of the unit, a multiple position switch at each station having a predetermined position individual to said unit, means for transmitting between said stations 9, current impulse of a character dependent upon the position of said unit when both of said switches are simultaneously in said predetermined positions, means for operating said switches to said predetermined positions, means responsive to the deenergization of said relay for initiating the operation of said operating means, control means at said other station for initiating the operation of said operating means, a select key at said other station having a normal position and an ofi-normal position arranged when in its normal position to permit the operation of said operating means to move said switches out of said predetermined positions and when in its off-normal position to prevent said operating means from moving said switches out of said predetermined positions, means controlled by said relay for eiTect-ing the movement of said switches out of said predetermined positions immediately when said relay is energized and said select key is in its normal position and after a predetermined longer time interval when said relay is deenergized and said select key is in its normal position, and means at said other station controlled by said impulse for selectively operating said indicating lamps in accordance with the character of said impulse and the length of time said switches remain in said predetermined positions. 7

30. In combination, two stations, an apparatus unit at one of said stations having a normal position and an oiT-normal position, means for moving said unit from each position to the other, a normally energized relay associated with said unit, means responsive to a change in the position of saidunit while said relay is energized for deenergizing said relay, indicating means at the other of said stations for indicating the position of said unit, said indicating means including an indicating lamp for each position of the unit and a disagreement lamp, a disagreement key associated with said indicating means and having positions corresponding to the positions of said unit, a multiple position switch at each station having a predetermined position individual to said unit, means for transmitting between said stations a current impulse of a character dependent upon the position of said unit when both of said switches are simultaneously in said predetermined positions, means for operating said switches to said predetermined positions, means responsive to the deenergization of said relay for initiating the operation of said .operating means, control means at said other station for initiating the operation of said operating means, a select key at said other station having a normal position and an off-normal position arranged when in its normal position to permit the operation of said operating means to move said switches out of said predetermined positions and when in its oif-normal position to r'event said operating 7 means from moving said switches out of said pre- 1 determined positions, means controlled by said relay for eifecting the movement of said switches out of said predetermined positions immediately when said relay is energized and said select key is in its normal position and after a predetermined longer time interval when said relay is deenergized and said select key is in its normal position, means at said other station controlled by said impulse for selectively operating said indicating lamps in accordance with the character of said impulse, and means at said other station controlled by the positions of said disagreement and select keys and the length of time said switches remain in said predetermined positions for operating said disagreement lamp in diiferent ways.

31. In combination, two stations, an apparatus unit at one of said stations having a normal position and an oif-normal position, means for moving said unit from each position to the other, a normally energized relay associated with said unit, means responsive to a change in the position of said unit while said relay is energized for deenergizing said relay, indicating means at the other of said stations for indicating the position of said unit, said indicating means including an indicating lamp for each position of the unit and a disagreement lamp, a disagreement key associated with said indicating means and having positions corresponding to the positions of said unit, a multiple position switch at each station having a predetermined position individual to said unit, means for transmitting between said stations a current impulse of a character dependent upon the position of said unit when both of said switches are simultaneously in said predetermined positions, means for operating said switches to said predetermined positions, means responsive to the deenergization of said relay for initiating the operation of said operating means, control means at said other station for initiating the operation of said operating means, a select key at said other station having a normal position and an off-normal position arranged when in its normal position to permit the operation of said operating means to move said switches out of said predetermined positions and when in its ofi-normal position to prevent said operating means from moving said switches out of said predetermined positions, means controlled by said relay for eiTecting the movement of said switches out of said predetermined positions immediately when said relay is energized and said select key is in its normal position and after a predetermined longer time interval when said relay is deenergized and said select key is in its normal position, means at said other station controlled by said impulse for selectively operating said indicating lamps in accordance with the character of said impulse, and means at said other station controlled by the positions of said disagreement and select keys and the length of time said switches remain in said predetermined positions for operating said disagreement lamp continuously if said select key is in its normal position and said unit is in its oil-normal position and said disagreement key is in its position corresponding to the normal position oi said unit when said impulse is transmitted and it said select key is in its off-normal position and the positions of said unit and disagreement key do not agree when said current impulse is transmitted and intermittently if said select key is in its normal position and said unit is in its normal position and said disagreement key is in its position corresponding to the normal position of said unit and said switches remain in said predetermined positions for said predetermined longer time interval when said impulse istransmitted.

32. In combination, two stations, an apparatus unit at one of said stations having a normal position and an oiT-normal position, means for moving said unit from each position to the other, a normally energized relay associated with said unit, means responsive to a change in the position of said unit while said relay is energized for deenergizing said relay, indicating means at the other of said stations for indicating the position of said unit, said indicating means including an indicating lamp for each position of the unit and a disagreement lamp, a disagreement key associated with said indicating means and having positions corresponding to the positions of said unit, a multiple position switch at each station having a predetermined position individual to said unit, means for transmitting between said stations a current impulse of a character dependent upon the position of said unit when both of said switches are simultaneously in said predetermined positions, means for operating said switches to said predetermined positions, means responsive to the deenergization of said relay for initiating the operation of said operating means,

control means at said other station for initiating the operation of said operating means, a select I key at said other station having a normal position and an off-normal position arranged when in its normal position to permit the operation of said operating means to move said switches out of said predetermined positions and when in its off-normal position to prevent said operating means from moving said switches out of said predetermined positions, means controlled by said relay for effecting the movement of said switches out of said predetermined positions immediately when said relay is energized and said select key is in its normal position and after a predetermined longer time interval when said relay is deenergized and said select key is in its normal position, means at said other station controlled by said impulse for selectively operating said indicating lamps in accordance with the character of said impulse, means at said other station controlled by the positions of said disagreement and select keys for operating said disagreement lam-p continuously if said select key is in its normal position and said unit is in its oifnormal position and said disagreement key is in its position corresponding to the normal position of said unit when said impulse is transmitted and if saidselect key is in its off-normal position and the positions of said unit and disagreement key do not agree when said current impulse is transmitted, and means for operating said disagreement lamp intermittently when said switches are restored to their idle positions if said select key and units are in their normal positions and said disagreement key is in its position corresponding to the normal position of said unit and said switches remain in said predetermined positions for said predetermined longer time interval when said impulse is transmitted.

CLYDE E. STEWART.

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