CA2074264A1 - Display for a circuit breaker trip unit - Google Patents
Display for a circuit breaker trip unitInfo
- Publication number
- CA2074264A1 CA2074264A1 CA 2074264 CA2074264A CA2074264A1 CA 2074264 A1 CA2074264 A1 CA 2074264A1 CA 2074264 CA2074264 CA 2074264 CA 2074264 A CA2074264 A CA 2074264A CA 2074264 A1 CA2074264 A1 CA 2074264A1
- Authority
- CA
- Canada
- Prior art keywords
- communication device
- trip unit
- display
- portable communication
- switch
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/02—Details
- H02H3/04—Details with warning or supervision in addition to disconnection, e.g. for indicating that protective apparatus has functioned
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/06—Arrangements for supplying operative power
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/006—Calibration or setting of parameters
Landscapes
- Electronic Switches (AREA)
- Emergency Protection Circuit Devices (AREA)
- Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)
- Breakers (AREA)
Abstract
A portable communication device communicates with a circuit breaker trip unit in a cost-efficient, power-effective manner. The portable communication device includes a keypad (10, 12), a display (78), an interface circuit (16) which couples data sent from the trip unit with the portable communication device, a microcomputer (13) which responds to the keypad (10, 12) and to the data sent from the trip unit for controlling the display (78), a local power source which provides power to the portable communication device, and a power switch which is responsive to the microcomputer for disabling the local power source during periods when data is not being received from the trip unit. The microcomputer may be arranged to directly control the power switch. In this manner the microcomputer can command the power switch to disable the local power when the absence of data from the trip unit indicates that power to the portable communication device is not needed.
Description
WO 92/09899 Pcrtus91/O9OOO
2 7 l i~, ~ ~ i ~!~
DISPLAY FOR A CIRCUIT BREA~R l'RIP IJNlT
Field Of The ~nvention The present invention relates generally to circuit breaker trip units and, 5 more particularly, to peripheral display devices communicating with circuit breaker trip units.
Background Of The ~nvention The practice of monitoring circuit breaker trip units is becoming 10 increasingly important. Proper monitoring can provide tangible benefits with respect to equipment operation and maintenance; therefore, significant return on investment. More specifically, these benefits include savings in terms of equipment ener~y costs and maintenance costs, better equipment utilization, and increased system reliability.
Known monitoring techniques have included a number of display units coupled to circuit breaker trip units. For instance, fixed display units have been permanently afflxed as part of the circuit breaker housing.
Unfortunately, this technique is disadvantageous in applications having a multitude of circuit breakers because of the cumulative cost of each display 20 unit in each circuit breaker housin~.
Similarly disadvantageous is the remotely located display unit which is cabled to a multitude of circuit breaker trip units. This type of implementation is costly in terms of the excessive cables that are required to interconnect the system, and of the labor that is required to install such ~YO 92/09899 PCr~US91/09000 2~ ~: 2 a system. Moreover, in many applications a remotely located display unit is not practical for monitoring and servicing the circuit breaker system.
In another known monitoring technique, a portable display unit is configured to draw power from the circuit breaker trip unit. This 5 technique is advantageous in that it overcomes many of the problems associated with the previously discussed techniques, but is disadvantageous in applications which require monitoring of the trip unit during system down times; that is, when the trip unit has experienced instantaneous or longer periods of power interruption. During these times, when power to 10 the trip unit is interrupted, power to the display unit is also interrupted.
Summary of the Invention It is a general object of the present invention to provide a reliable, power conservative system for monitoring the operation of a circuit 15 breaker trip unit.
It is a more specific object of the present invention to provide such a system that can be easily retro-fit with existing circuit breaker arrangements.
In accordance with a preferred embodiment, the present invention 20 provides a portable communica~ion device for communicating with a circuit breaker trip unit, in which the portab]e communication device includes a keypad, a display, an interface circuit whlch couples data sent from the trip unit with the portab]e communication device, a contro1 circuit which responds to the keypad and to the data sent from the trip unit for 25 controllin~ the display, a local power source which provides power to the WO 92/09899 ~ ,~ t;~ PCI'/US91/09oO0 portable communication device, and a power switch which is responsive to the control circuit for disabling the local power source during periods when data is not being received from the trip unit.
S Brief D~scription Of The Drawin~s Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings In which:
FI&. la is a schematic diagram of a portable communication device, 10 in accordance with the present invention, for monitoring a circuit breaker trip system;
FIG. lb is a perspective view diagram of the portable communication device shown in FIG. la; and FIGS. 2-7 comprise a flow chart illustratin~ a preferred manner in 15 which the microcontroller of FIGS. la and lb may be programmed.
While the invention is susceptible to various modifications and alternative fo~ns, a specific embodiment thereof has been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that it is not intended to limit the invention to the 20 particular fonns disclosed. On the contrary, the intent;on is to cover all modif;cations, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. ~ -f w0 92~09899 Pcr/us91/osooo (J
Descripbon Of The Preferred Embodiments The present invention is particularly useful in industrial applications wherein a plurality of circuit breaker trip units are periodically monitored and serviced. In such an environment, the portabili~,r of the present 5 invention allows it to be interconnected with each trip unit sequentially so as to minimize the number of components.
In FIG. la, a preferred embodiment of the present invention is shown in schematic form to include a pair of push buttons 10 and 12 implementing a simple keypad, a display circuit 14, an interface circuit 16 10 coupling data sent from a circuit breaker trip unit (not shown), a microcontroller 18 and a power control circuit 20.
The microcontroller 18, which is preferably implemented using a Motorola 68HC7OSC8-type IC (integrated circuit), operates as the control center for the portable communication device illustrated in FIG. 1. The 15 microcontroller 18 receives both user and trip unit type data. User data is received by the microcontroller 18 via push buttons 10 and 12, using pull-down 100 kOhm resistors 22-23 and a menu driven computer program (FIGS. 2-7). Trip unit data is received by the microcontroller 18 at a peripheral port (e.g., PD0) via the interface circuit 16, which includes a 20 fiber optic connector 26 for electrically isolating the portable communication device of FIG. la from the trip unit, a 100 kOhm termination resistor 28 and conventional amp]ification circuit~y for conditioning the trip unit data for reception by the microcontroller 18.
The amplification circuitly includes a pair of operational amplifier 25 circuits and a transistor circuit. The operational amplifier circuits, which WO 92/09899 ~ ~ 7 ~ PCr/US91/09OOo .` 5 may both be implemented using LM358-type ICs, include an inverting amplifier 30 and a conventional negative feedbac3c amplifier 32. The resistor 34 in the feedback path of the inverting amplifier 30 may be implemented using a 1.5 mega-Ohm resistor, and the amplification for the 5 amplifier 32 may be implemented usin~ a 470 kOhm resistor 36 and a 10 kOhm resistor 38. The final stage of the interface circuit 16 includes a BS170 type FET (field-effect transistor) 40 and bias resistors 42 and 44 - having 10 kOhm and 100 kOhm values, respectively.
The power control circuit 20 is another important part of the 10 portable communication device of FIG. la. It allows the user to power-on the portable communication device via momentaly push-button switch 50, and allows the microcontroller 18 to automatically power-down the portable communication device in the event that the microcontroller 18 does not re- eive data from the trip unit for a prescribed period of time.
15 This si~nificantly extends the life of the power source (battery 52~ for the portable communication device in that it maximizes its efficiency.
More specifically, diode 54 is momentarily forward biased upon power-up, via push-button switch 50, to allow a FET 56 to engage a bipolar transistor 58, which in turn drives an LP2950 type five-Yolt 20 regulator 60 to provide Vcc power, using a 0.1 microFarad capacitor 62 to suppress noise. The FET 56 may be implemented usin~ a BS170 type component, the transistor 58 usin~ a 2N3906 type component and resistors 64, 66 and 68 using 100 kOhm, 27 kOhm and 10 kOhm values, respectively. Once the microcontroller 18 receives operating power, it 25 drives line 72 high (via port PA1) to folward bias a diode 74, which WO 92/098~9~,'3~ ~ PCr/US91/09000 continues to allow the FET 56 to engaBe the bipolar transistor 58 so as to maintain Vcc. The microcontroller 18 then employs a software timer to time periods during which no data is received by the trip unit. If the duration exceeds a prescribed limit, the microcontroller 18 drives line 72 5 low to disengage the bipolar transistor 58 and power-down the portable communication device so that power from the battery is not wasted.
The display circuit 14 is controlled conventionally, using the PB0-PB7 peripheral ports of the microcontroller 18 to drive a 4 by 16 LCD
(liquid crystal display) 78, which is preferably implemented using an 10 LM73X4C16CX type component available from Densitron. A negative voltage generator 80, such as an Intersil ICL7660 component, in conjunction with a pair of 10 microFarad capacitors 82 and 84, is used to provide the requisite negative voltage to the LCD 78. Resistors ~,6 and 88 may be implemented using a number of different values depending on the 15 desired bri~htness of the LCD 78. In one application, for example, 4.7k kOhm and lk kOhm values may be used for resistors 86 and 88, respectively.
FIG. lb illustrates a preferred embodiment of the portable communication device from a perspective view. The device incJudes an 20 enclosed housin~ 90, an optical waveguide 92, a battery compartment 94, and the switches 10, 12, 50, the display 78 and the connector 26, discussed ' above in connection with FIG. ~a. - , FIGS. 2-7 comprise a flow chart for implemen~ing the microcontroller 18 of FIG. 1. More specifically, FIG. 2 represents a flow 25 chart for the main operating progMm of the microcontroller. FIGS. 3 anL3 WO 92/09899 2 ~ Pcr/Us9]/o9ooo S constitute respective flow charts for interrupt routines which are respect;vely serviced in response to a timer which is inten~a] to the microcontroller and in a response to data being received from the trip unit via the SCI port of the microcontroller. The remaining charts depicted in 5 FIGS. 4 and ~7 are subroutines which are respectively called in response to the reception of data messages, for periodically looking for keypad data and for periodically contro]ling the display.
The flow chart of FIG. 2 be~ins upon power-up as depicted at block 100. At blocks 102 and 104, the microcontrol]er initializes its various ports 10 and system variables, including driving the output line (72 of FIG. la), which maintains the local power source in the "on" condition.
At block 106, the microcontroller performs a test to determine if its SCI data register is full. If the SCI data register is full, flow proceeds from block 106 to block 108 where the subroutine of FIG. 4 is serviced. Upon 15 returning from the subroutine of FIG. 4, or from block 106 if the SCI data register is not full, flow proceeds to block 11û.
At block 110, the microcontroller performs a test to determine if the display reset timer has timed out. The display reset timer from block 110 and other timers to be discussed in connection with this flow chart of 20 FIG. 2 are controlled using the interrupt service routine of FIG. 3. The display reset timer is used to indicate when the display (7~ of FIG. la) is ready to be controlled after power-up, since a 15 millisecond post-power-up delay is specified for the preferred LCD component. Accordingly, if the display reset timer is equal to 0, then the 15 millisecond delay has - . . .. . ..
-- .
. .
wo 92/09899 ~ ~ c3 ~ Pcr/us9l/o9ooo elapsed, and the microcontroller proceeds to block 112 to reset the LCD in preparation for subsequent use and to disable the timer.
At block 114, the microcontroller deterrnines whether or not it is time to service the keypad. A keypad service timer, which is a]so 5 maintained using the interrupt service routine of FIG. 3, is regularly decremented until it reaches 0, at which time the microcontroller proceeds to deterrnine if any data had been entered via the keypad. Thus~ at block 116 the microcontroller performs a test to determine if all the keys have been serviced. This is determined by checking if the key-ready flag is set (see FIG. 6). If all the keys have been serviced, flow proceeds to block 118 where the microcontroller calls the keypad service subroutine of FIG.
6. From block 118, or if all the keys have not been selviced at block 116, flow proceeds to block 120 where the keypad selvice timer is restored to its original value. From block 120, flow proceeds to block 122.
At block 122, a test is performed to determine if the display reset timer has been disabled. If the display reset timer has been disabled, then - the 15 rnillisecond delay after power-up has elapsed, and flow can proceed to block 124 where the display service subroutine of FIG. 7 is called for servicing the LCD.
At block 126, a test is performed to determine if the prescribed time period, durin~ which no trip data has been received, has lapsed. A
shut down timer, contro]]ed by the routine of FIG. 3, is used for this purpose as depicted in b]ock 126. If that prescribed peAod has ]apsed, flow procecds to block 128 where the appropriate power control bit (line 72) is set ]ow to shut down power to the portab]e communication device.
WO 92/09899 2 ~ 2 ~3 ~ Pcr/us9l/
From block 128, or in response to the shut down timer not being decremented to 0, flow returns to block 106.
The timer interrupt selvice routine, which is depicted in FIG. 3, occurs each millisecond. The flow chart begins at block 132 and, at block S 134, the microcontroller sets the output compare register to interrupt at the next millisecond.
At blocks 136, 138 and 140, the display-reset, keypad service and 125-millisecond timers are decremented. The 125-millisecond timer is used to decrement the shut-down timer and the display timer, which have 10 relatively long time periods. At block 142, the microcontroller performs a test to determine if the 125-millisecond timer has been decremented to 0.
lf so, the 125-millisecond timer is refreshed and flow proceeds to blocks 144 and 146 to decrement the display and shut-down timers. From block 146, and from block 142 if the 125-millisecond timer has not been 15 decremented to 0, flow proceeds to block 148, where the microcontroller executes a return from interrupt command.
FIG. 4 illustrates a preferred manner of implementin~ bloclc 108 of FIG. 2: the SCI data subroutine. The subroutine is entered at block 152, and, at block 153, the microcontroller interprets the data packet received 20 Yia the SCI port. The received data packet may be related to confi~uration data or operating-status data. Each such type of data corresponds to the type of multi-byte packet that is being sent from the trip unit. For further infonnation concerning the data packet structure, reference may be made to copending U.S. Patent Application No.
25 07/503,267, filed on April 2, 1990, incorporated in its entirety by reference.
WO 92/09899 ~ c~ PCr/lJSg1/09000 If the received data is configuration data, flow proceeds from block 153 to block 154 where the configuration data memory locations are updated. lf the received data is not confi~uration data, flow proceeds from block 153 to block 155 where a test is performed to determine if it is status data. If 5 so, the status data memory locations are updated at block 156. At block 157, the microcontroller updates its record of the trip status. As discussed in the above copendin~ application, the trip status includes long time trip, short time trip, instantaneous trip, ~round fault trip and normal operation.
At block 158, the microcontroller clears the SCI data ready fla8 so that it 10 can be informed the next time a data packet h s been received via the SCI
port. The microcontroller then executes a return from subroutine command, as depicted in block 160.
FIG. 5 illustrates the SCI interrupt routine, which is serviced each time a byte is received via the SCI port. Upon enterin~ the routine at lS block 164, the microcontroller performs a test to determine if any errors have been received, depicted at block 166. If one or more errors were received via the SCI port, flow proceeds from block 166 to block 168 where the microcontroller resets the SCI port and an associated messa~e byte counter, which is used to track how many bytes of a particular packet 20 had been re~eived so that errors are not accumulated. From block 168, flow proceeds to block 170 where the microcontroller refreshes the shutdown timer, since data has been received from the trip unit, and the portable communication device of FIG. la need not be powered down., From block 170, flow proceeds to block 172 where the microcontroller 25 executes a return from interrupt command.
Wo 92/09899 ~ iv ~ fJ i~ Pcr/us9l/o9ooo If errors are not detected via block 166, flow proceeds to block 174 where a test is performed to determine if the received data byte constitutes the beginning of a data message. If not, flow proceeds to block 176 where the microcontroller stores the data byte and increments the data byte 5 counter in order to track the number of received bytes in the instant packet. From block 176, flow proceeds to bloclc 178 where a test is performed to determine if the received byte constitutes the end of a data message or packet. If the received byte does constitute the end of a data message, flow proceeds to b]ock 180 where a test is perfonned to 10 determine if there are any byte or bit errors in the packet that has been received. This is preferably done by performing a conventional checksum test. If the checksum test passes, flow proceeds to block 182 where the microcontroller sets the SCI data ready flag of block 158 (FIG. 4) to record that a paclcet has been received. From block 182, flow proceeds to 15 previously discussed block 168.
If the microcontroller determines that the received byte is the beginning of a data message or packet, flow proceeds from block 174 to block 184 where the microcontroller begins to form the packet by storing the be~inning of the message and resetting the byte counter indicating the 20 number of bytes that have been received for the packet. From bloc3c 184, from block 178 if the received byte constitutes the end of a data message and from block l80 if the checksum test fails, flow proceeds to block 170 to refresh the shutdo~n timer before returning from the interrupt routine.
FIG. 6 illustrates the keypad service subroutine depicted in block 25 ~18 of FIG. 2. After entering the routine at block 188, flow proceeds to '` W0 92/09899 ~ 12 PCr/US91/09000 block 190 where the microcontroller reads the port at which the keypad (set of push-button switches) is connected. At block 192, the microcontroller determines if a push-button switch has been depressed or released by comparing the present state of the push-button switch port to S its previous state. If the present and the previous states of the push-button switch port are the same, f30w proceeds from block 192 to block 194 where the microcontro]ler executes a return from subroutine command.
If the microcontroller determines that a push-button switch has been depressed or released, flow proceeds from block 192 to block 196 10 where the microcontroller once a~ain reads the same port At this point in the flow chart, the microcontroller initiates a s vitch debouncing procedure.
If the microcontroller reads the push-button switch port three times and concludes that the data in the port has not changed at each one of the three reads, then the switch has been debounced. Thus, from block 196, 15 flow proceeds to block 198 where the microcontro]ler makes the first comparison. From b]ock 19B, flow proceeds to block 200 if the successive data port reads are not the same.
At block 200 a counter, which is used for tracking the number of times the comparison has been made, is cleared. If the success reads at 20 block 198 are the same, flow proceeds from block 198 to block 202 where the counter is incremented.
From block 202, flow proceeds to block 204 where a test is performed to determine if three successive reads have taken place with the same data being read at the port. If not, flow returns from block 204 to 25 block 196 for the next successive read of the push-button switch port.
WO 92/09899 Pcr/ussltog From block 204, flow proceeds to block 206 where a test is performed to determine if the push button switch has been released. If the push-button switch has been released, flow proceeds to block 208 where the microcontroller updates a register storing the status of the 5 associated push-button switch and sets a key ready flag to record that a switch has been pressed and released, the latter of which must happen for the microcontroller to act on the data input by the user. From block 206, if the switch has not been released by this time, flow proceeds to block 194 where the microcontroller executes a return from subroutine command.
FIG. 7 illustrates the display service subroutine which is depicted at block 124 of FIG. 2. The subroutine of FIG. 7 changes inforrnation on the display in response to: the 500 millisecond timer timing out, a user request via ~he kegpad, or trip unit data requiring a change. Preferably, there are two types of display modes, a current-related mode and a configuration 15 mode with SLY subtypes associated with the configuration mode. The current-related information mode displays the amperage for each of three phases plus ground fault. The configuration submodes display: (1) identification of breaker type, current sensor size and amperage rating; (2) ~ong time trip settings, pick-up settings in amperes and in time; (3) short-20 time trip settiDgs, pick-up settings in amperes and in time; (4) instantaneous trip settings and associated pick-up settinL~s; (5) ground fault trip settings and associated pick-up settings; and (6) the revision number for the hardware and firmware.
After entering the subroutine at block 210 of FIG. 7, flow proceeds 25 to block 212 to determine if a nag has been set, which flag indicates that O 92~09899 t ~ PCT/US91/09000 another portion of the display needs to be written. Only one portion of the display is written at a time. If other portions of the display have not been written, then the display is still in progress. If another display portion needs to be written, flow proceeds from block 212 to block 214 where the 5 microcontroller updates the display using conventional line-by-line LCD
writing techniques. From block 214, flow proceeds to block 216 where the microcontroller performs a return from subroutine command.
From block 212, flow proceeds to block 218 if a display update is not in progress to determine if the key-ready flag is set (see block 208 of 10 FIG. 6). If the key-ready flag is set, then a key or switch was detected as being depressed and released, and flow proceeds to block 220.
If the key-ready flag 2s not set, flow proceeds from block 218 to block 2æ where the microcontroller performs a test to determine if current-related information is being displayed; for example, the display of 15 current in each of the three phases and ground fault.
If the display is not displaying current-related information, flow proceeds from block 222 to block 224 where the microcontroller performs a test to determine if the display is displaying configuration information and the configuration requires changing. If at least one of these conditions 20 is not met, no further action is necessary and 90w proceeds to b]ock 216 for exiting the subroutine. If both of these conditions are met, flow proceeds from block 224 to block 226 where the microcontroller sets up for writing the new configuration. This may be done by writing a portion of the new display during this visit to the display service routine and the WO 92/09899 15 2 ~ 7 ,~, ~t !~
remaining portion during the next visit. From block 226, flow proceeds to block 214 for writing the new configuration data on the display.
~ rom block 222, flow proceeds to block 228 if the information bein~
displayed is current-related information. At block 22~, the current-related S information is set for being updated (or refreshed) by setting a flag to record that updates should only pertain to the numbers, e.g., the displayed amperages for the various phases and ground fault. This updating or refreshing in the display mode for "current" is set to occur every 500 milliseconds. From block 228, flow proceeds to block 214 for the actua]
10 refreshing of the current-related information on the display.
At block 220, if the push-button switch corresponding to a function key is detected as being depressed and released, flow proceeds to block 232 where the microcomputer toggles the display from the configuration-type display to the current-related information display or vice-versa. From 15 block 232, flow proceeds to block 214 where the display is actually written to for the change indication of block 232.
From block 220, flow proceeds to block 233 if the function switch was not engaged. At block 233, a test is performed to determine if current-related information is being displayed. If so, en~agement of the 2û other switch, which activated the key ready flag, was improper and flow proceeds to block 216. From block 233, flow proceeds to block 236 if the microcontroller determines that the display is not displayin~ current-related information.
At this point, the microcontroller has determined that a switch was 25 depressed and released (block 218) and that it was not the "function"
?J~r~ J~ 16 PCI/US91/09000 switch (block 22~). Since the only other switch is the "select" switch, the microcontroller deduces that the "select" switch has been depressed and released. The "select" switch is engaged by the user when it is desired to switch to the next of the six submodes of the configuration mode. If the 5 last of the six submodes is displayed when the "select" switch is en~aged, a transition to the first submode is displayed. From block 236, flow proceeds to blocks 232 and 214 to chan~e the display.
While the invention has been particularly shown and described with reference to a particular embodiment, various modifications may be made.
10 For example, the microcontroller (or microcomputer) 18 of FIG. la may be implemented using discrete circuits. Further, rather than reactivating power solely by the switch 50 of FIG. la, power may be continuously provided from the battery to a data sensing circuit, such as the interface circuit 16 of FIG. la, so that the data sensing circuit momentarily forward 15 biases the diode 54 to initiate power to the device of FIG. 1. A
conventional "one-shot" circuit may "OR"-tied with the switch S0 to couple the data sensing circuit to the diode 54. It will be recognized by those skilled in ~he art that such modifications and changes may be made to the present invention described above without departing from the spirit and ~0 scope thereof.
- ` ;
,
DISPLAY FOR A CIRCUIT BREA~R l'RIP IJNlT
Field Of The ~nvention The present invention relates generally to circuit breaker trip units and, 5 more particularly, to peripheral display devices communicating with circuit breaker trip units.
Background Of The ~nvention The practice of monitoring circuit breaker trip units is becoming 10 increasingly important. Proper monitoring can provide tangible benefits with respect to equipment operation and maintenance; therefore, significant return on investment. More specifically, these benefits include savings in terms of equipment ener~y costs and maintenance costs, better equipment utilization, and increased system reliability.
Known monitoring techniques have included a number of display units coupled to circuit breaker trip units. For instance, fixed display units have been permanently afflxed as part of the circuit breaker housing.
Unfortunately, this technique is disadvantageous in applications having a multitude of circuit breakers because of the cumulative cost of each display 20 unit in each circuit breaker housin~.
Similarly disadvantageous is the remotely located display unit which is cabled to a multitude of circuit breaker trip units. This type of implementation is costly in terms of the excessive cables that are required to interconnect the system, and of the labor that is required to install such ~YO 92/09899 PCr~US91/09000 2~ ~: 2 a system. Moreover, in many applications a remotely located display unit is not practical for monitoring and servicing the circuit breaker system.
In another known monitoring technique, a portable display unit is configured to draw power from the circuit breaker trip unit. This 5 technique is advantageous in that it overcomes many of the problems associated with the previously discussed techniques, but is disadvantageous in applications which require monitoring of the trip unit during system down times; that is, when the trip unit has experienced instantaneous or longer periods of power interruption. During these times, when power to 10 the trip unit is interrupted, power to the display unit is also interrupted.
Summary of the Invention It is a general object of the present invention to provide a reliable, power conservative system for monitoring the operation of a circuit 15 breaker trip unit.
It is a more specific object of the present invention to provide such a system that can be easily retro-fit with existing circuit breaker arrangements.
In accordance with a preferred embodiment, the present invention 20 provides a portable communica~ion device for communicating with a circuit breaker trip unit, in which the portab]e communication device includes a keypad, a display, an interface circuit whlch couples data sent from the trip unit with the portab]e communication device, a contro1 circuit which responds to the keypad and to the data sent from the trip unit for 25 controllin~ the display, a local power source which provides power to the WO 92/09899 ~ ,~ t;~ PCI'/US91/09oO0 portable communication device, and a power switch which is responsive to the control circuit for disabling the local power source during periods when data is not being received from the trip unit.
S Brief D~scription Of The Drawin~s Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings In which:
FI&. la is a schematic diagram of a portable communication device, 10 in accordance with the present invention, for monitoring a circuit breaker trip system;
FIG. lb is a perspective view diagram of the portable communication device shown in FIG. la; and FIGS. 2-7 comprise a flow chart illustratin~ a preferred manner in 15 which the microcontroller of FIGS. la and lb may be programmed.
While the invention is susceptible to various modifications and alternative fo~ns, a specific embodiment thereof has been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that it is not intended to limit the invention to the 20 particular fonns disclosed. On the contrary, the intent;on is to cover all modif;cations, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. ~ -f w0 92~09899 Pcr/us91/osooo (J
Descripbon Of The Preferred Embodiments The present invention is particularly useful in industrial applications wherein a plurality of circuit breaker trip units are periodically monitored and serviced. In such an environment, the portabili~,r of the present 5 invention allows it to be interconnected with each trip unit sequentially so as to minimize the number of components.
In FIG. la, a preferred embodiment of the present invention is shown in schematic form to include a pair of push buttons 10 and 12 implementing a simple keypad, a display circuit 14, an interface circuit 16 10 coupling data sent from a circuit breaker trip unit (not shown), a microcontroller 18 and a power control circuit 20.
The microcontroller 18, which is preferably implemented using a Motorola 68HC7OSC8-type IC (integrated circuit), operates as the control center for the portable communication device illustrated in FIG. 1. The 15 microcontroller 18 receives both user and trip unit type data. User data is received by the microcontroller 18 via push buttons 10 and 12, using pull-down 100 kOhm resistors 22-23 and a menu driven computer program (FIGS. 2-7). Trip unit data is received by the microcontroller 18 at a peripheral port (e.g., PD0) via the interface circuit 16, which includes a 20 fiber optic connector 26 for electrically isolating the portable communication device of FIG. la from the trip unit, a 100 kOhm termination resistor 28 and conventional amp]ification circuit~y for conditioning the trip unit data for reception by the microcontroller 18.
The amplification circuitly includes a pair of operational amplifier 25 circuits and a transistor circuit. The operational amplifier circuits, which WO 92/09899 ~ ~ 7 ~ PCr/US91/09OOo .` 5 may both be implemented using LM358-type ICs, include an inverting amplifier 30 and a conventional negative feedbac3c amplifier 32. The resistor 34 in the feedback path of the inverting amplifier 30 may be implemented using a 1.5 mega-Ohm resistor, and the amplification for the 5 amplifier 32 may be implemented usin~ a 470 kOhm resistor 36 and a 10 kOhm resistor 38. The final stage of the interface circuit 16 includes a BS170 type FET (field-effect transistor) 40 and bias resistors 42 and 44 - having 10 kOhm and 100 kOhm values, respectively.
The power control circuit 20 is another important part of the 10 portable communication device of FIG. la. It allows the user to power-on the portable communication device via momentaly push-button switch 50, and allows the microcontroller 18 to automatically power-down the portable communication device in the event that the microcontroller 18 does not re- eive data from the trip unit for a prescribed period of time.
15 This si~nificantly extends the life of the power source (battery 52~ for the portable communication device in that it maximizes its efficiency.
More specifically, diode 54 is momentarily forward biased upon power-up, via push-button switch 50, to allow a FET 56 to engage a bipolar transistor 58, which in turn drives an LP2950 type five-Yolt 20 regulator 60 to provide Vcc power, using a 0.1 microFarad capacitor 62 to suppress noise. The FET 56 may be implemented usin~ a BS170 type component, the transistor 58 usin~ a 2N3906 type component and resistors 64, 66 and 68 using 100 kOhm, 27 kOhm and 10 kOhm values, respectively. Once the microcontroller 18 receives operating power, it 25 drives line 72 high (via port PA1) to folward bias a diode 74, which WO 92/098~9~,'3~ ~ PCr/US91/09000 continues to allow the FET 56 to engaBe the bipolar transistor 58 so as to maintain Vcc. The microcontroller 18 then employs a software timer to time periods during which no data is received by the trip unit. If the duration exceeds a prescribed limit, the microcontroller 18 drives line 72 5 low to disengage the bipolar transistor 58 and power-down the portable communication device so that power from the battery is not wasted.
The display circuit 14 is controlled conventionally, using the PB0-PB7 peripheral ports of the microcontroller 18 to drive a 4 by 16 LCD
(liquid crystal display) 78, which is preferably implemented using an 10 LM73X4C16CX type component available from Densitron. A negative voltage generator 80, such as an Intersil ICL7660 component, in conjunction with a pair of 10 microFarad capacitors 82 and 84, is used to provide the requisite negative voltage to the LCD 78. Resistors ~,6 and 88 may be implemented using a number of different values depending on the 15 desired bri~htness of the LCD 78. In one application, for example, 4.7k kOhm and lk kOhm values may be used for resistors 86 and 88, respectively.
FIG. lb illustrates a preferred embodiment of the portable communication device from a perspective view. The device incJudes an 20 enclosed housin~ 90, an optical waveguide 92, a battery compartment 94, and the switches 10, 12, 50, the display 78 and the connector 26, discussed ' above in connection with FIG. ~a. - , FIGS. 2-7 comprise a flow chart for implemen~ing the microcontroller 18 of FIG. 1. More specifically, FIG. 2 represents a flow 25 chart for the main operating progMm of the microcontroller. FIGS. 3 anL3 WO 92/09899 2 ~ Pcr/Us9]/o9ooo S constitute respective flow charts for interrupt routines which are respect;vely serviced in response to a timer which is inten~a] to the microcontroller and in a response to data being received from the trip unit via the SCI port of the microcontroller. The remaining charts depicted in 5 FIGS. 4 and ~7 are subroutines which are respectively called in response to the reception of data messages, for periodically looking for keypad data and for periodically contro]ling the display.
The flow chart of FIG. 2 be~ins upon power-up as depicted at block 100. At blocks 102 and 104, the microcontrol]er initializes its various ports 10 and system variables, including driving the output line (72 of FIG. la), which maintains the local power source in the "on" condition.
At block 106, the microcontroller performs a test to determine if its SCI data register is full. If the SCI data register is full, flow proceeds from block 106 to block 108 where the subroutine of FIG. 4 is serviced. Upon 15 returning from the subroutine of FIG. 4, or from block 106 if the SCI data register is not full, flow proceeds to block 11û.
At block 110, the microcontroller performs a test to determine if the display reset timer has timed out. The display reset timer from block 110 and other timers to be discussed in connection with this flow chart of 20 FIG. 2 are controlled using the interrupt service routine of FIG. 3. The display reset timer is used to indicate when the display (7~ of FIG. la) is ready to be controlled after power-up, since a 15 millisecond post-power-up delay is specified for the preferred LCD component. Accordingly, if the display reset timer is equal to 0, then the 15 millisecond delay has - . . .. . ..
-- .
. .
wo 92/09899 ~ ~ c3 ~ Pcr/us9l/o9ooo elapsed, and the microcontroller proceeds to block 112 to reset the LCD in preparation for subsequent use and to disable the timer.
At block 114, the microcontroller deterrnines whether or not it is time to service the keypad. A keypad service timer, which is a]so 5 maintained using the interrupt service routine of FIG. 3, is regularly decremented until it reaches 0, at which time the microcontroller proceeds to deterrnine if any data had been entered via the keypad. Thus~ at block 116 the microcontroller performs a test to determine if all the keys have been serviced. This is determined by checking if the key-ready flag is set (see FIG. 6). If all the keys have been serviced, flow proceeds to block 118 where the microcontroller calls the keypad service subroutine of FIG.
6. From block 118, or if all the keys have not been selviced at block 116, flow proceeds to block 120 where the keypad selvice timer is restored to its original value. From block 120, flow proceeds to block 122.
At block 122, a test is performed to determine if the display reset timer has been disabled. If the display reset timer has been disabled, then - the 15 rnillisecond delay after power-up has elapsed, and flow can proceed to block 124 where the display service subroutine of FIG. 7 is called for servicing the LCD.
At block 126, a test is performed to determine if the prescribed time period, durin~ which no trip data has been received, has lapsed. A
shut down timer, contro]]ed by the routine of FIG. 3, is used for this purpose as depicted in b]ock 126. If that prescribed peAod has ]apsed, flow procecds to block 128 where the appropriate power control bit (line 72) is set ]ow to shut down power to the portab]e communication device.
WO 92/09899 2 ~ 2 ~3 ~ Pcr/us9l/
From block 128, or in response to the shut down timer not being decremented to 0, flow returns to block 106.
The timer interrupt selvice routine, which is depicted in FIG. 3, occurs each millisecond. The flow chart begins at block 132 and, at block S 134, the microcontroller sets the output compare register to interrupt at the next millisecond.
At blocks 136, 138 and 140, the display-reset, keypad service and 125-millisecond timers are decremented. The 125-millisecond timer is used to decrement the shut-down timer and the display timer, which have 10 relatively long time periods. At block 142, the microcontroller performs a test to determine if the 125-millisecond timer has been decremented to 0.
lf so, the 125-millisecond timer is refreshed and flow proceeds to blocks 144 and 146 to decrement the display and shut-down timers. From block 146, and from block 142 if the 125-millisecond timer has not been 15 decremented to 0, flow proceeds to block 148, where the microcontroller executes a return from interrupt command.
FIG. 4 illustrates a preferred manner of implementin~ bloclc 108 of FIG. 2: the SCI data subroutine. The subroutine is entered at block 152, and, at block 153, the microcontroller interprets the data packet received 20 Yia the SCI port. The received data packet may be related to confi~uration data or operating-status data. Each such type of data corresponds to the type of multi-byte packet that is being sent from the trip unit. For further infonnation concerning the data packet structure, reference may be made to copending U.S. Patent Application No.
25 07/503,267, filed on April 2, 1990, incorporated in its entirety by reference.
WO 92/09899 ~ c~ PCr/lJSg1/09000 If the received data is configuration data, flow proceeds from block 153 to block 154 where the configuration data memory locations are updated. lf the received data is not confi~uration data, flow proceeds from block 153 to block 155 where a test is performed to determine if it is status data. If 5 so, the status data memory locations are updated at block 156. At block 157, the microcontroller updates its record of the trip status. As discussed in the above copendin~ application, the trip status includes long time trip, short time trip, instantaneous trip, ~round fault trip and normal operation.
At block 158, the microcontroller clears the SCI data ready fla8 so that it 10 can be informed the next time a data packet h s been received via the SCI
port. The microcontroller then executes a return from subroutine command, as depicted in block 160.
FIG. 5 illustrates the SCI interrupt routine, which is serviced each time a byte is received via the SCI port. Upon enterin~ the routine at lS block 164, the microcontroller performs a test to determine if any errors have been received, depicted at block 166. If one or more errors were received via the SCI port, flow proceeds from block 166 to block 168 where the microcontroller resets the SCI port and an associated messa~e byte counter, which is used to track how many bytes of a particular packet 20 had been re~eived so that errors are not accumulated. From block 168, flow proceeds to block 170 where the microcontroller refreshes the shutdown timer, since data has been received from the trip unit, and the portable communication device of FIG. la need not be powered down., From block 170, flow proceeds to block 172 where the microcontroller 25 executes a return from interrupt command.
Wo 92/09899 ~ iv ~ fJ i~ Pcr/us9l/o9ooo If errors are not detected via block 166, flow proceeds to block 174 where a test is performed to determine if the received data byte constitutes the beginning of a data message. If not, flow proceeds to block 176 where the microcontroller stores the data byte and increments the data byte 5 counter in order to track the number of received bytes in the instant packet. From block 176, flow proceeds to bloclc 178 where a test is performed to determine if the received byte constitutes the end of a data message or packet. If the received byte does constitute the end of a data message, flow proceeds to b]ock 180 where a test is perfonned to 10 determine if there are any byte or bit errors in the packet that has been received. This is preferably done by performing a conventional checksum test. If the checksum test passes, flow proceeds to block 182 where the microcontroller sets the SCI data ready flag of block 158 (FIG. 4) to record that a paclcet has been received. From block 182, flow proceeds to 15 previously discussed block 168.
If the microcontroller determines that the received byte is the beginning of a data message or packet, flow proceeds from block 174 to block 184 where the microcontroller begins to form the packet by storing the be~inning of the message and resetting the byte counter indicating the 20 number of bytes that have been received for the packet. From bloc3c 184, from block 178 if the received byte constitutes the end of a data message and from block l80 if the checksum test fails, flow proceeds to block 170 to refresh the shutdo~n timer before returning from the interrupt routine.
FIG. 6 illustrates the keypad service subroutine depicted in block 25 ~18 of FIG. 2. After entering the routine at block 188, flow proceeds to '` W0 92/09899 ~ 12 PCr/US91/09000 block 190 where the microcontroller reads the port at which the keypad (set of push-button switches) is connected. At block 192, the microcontroller determines if a push-button switch has been depressed or released by comparing the present state of the push-button switch port to S its previous state. If the present and the previous states of the push-button switch port are the same, f30w proceeds from block 192 to block 194 where the microcontro]ler executes a return from subroutine command.
If the microcontroller determines that a push-button switch has been depressed or released, flow proceeds from block 192 to block 196 10 where the microcontroller once a~ain reads the same port At this point in the flow chart, the microcontroller initiates a s vitch debouncing procedure.
If the microcontroller reads the push-button switch port three times and concludes that the data in the port has not changed at each one of the three reads, then the switch has been debounced. Thus, from block 196, 15 flow proceeds to block 198 where the microcontro]ler makes the first comparison. From b]ock 19B, flow proceeds to block 200 if the successive data port reads are not the same.
At block 200 a counter, which is used for tracking the number of times the comparison has been made, is cleared. If the success reads at 20 block 198 are the same, flow proceeds from block 198 to block 202 where the counter is incremented.
From block 202, flow proceeds to block 204 where a test is performed to determine if three successive reads have taken place with the same data being read at the port. If not, flow returns from block 204 to 25 block 196 for the next successive read of the push-button switch port.
WO 92/09899 Pcr/ussltog From block 204, flow proceeds to block 206 where a test is performed to determine if the push button switch has been released. If the push-button switch has been released, flow proceeds to block 208 where the microcontroller updates a register storing the status of the 5 associated push-button switch and sets a key ready flag to record that a switch has been pressed and released, the latter of which must happen for the microcontroller to act on the data input by the user. From block 206, if the switch has not been released by this time, flow proceeds to block 194 where the microcontroller executes a return from subroutine command.
FIG. 7 illustrates the display service subroutine which is depicted at block 124 of FIG. 2. The subroutine of FIG. 7 changes inforrnation on the display in response to: the 500 millisecond timer timing out, a user request via ~he kegpad, or trip unit data requiring a change. Preferably, there are two types of display modes, a current-related mode and a configuration 15 mode with SLY subtypes associated with the configuration mode. The current-related information mode displays the amperage for each of three phases plus ground fault. The configuration submodes display: (1) identification of breaker type, current sensor size and amperage rating; (2) ~ong time trip settings, pick-up settings in amperes and in time; (3) short-20 time trip settiDgs, pick-up settings in amperes and in time; (4) instantaneous trip settings and associated pick-up settinL~s; (5) ground fault trip settings and associated pick-up settings; and (6) the revision number for the hardware and firmware.
After entering the subroutine at block 210 of FIG. 7, flow proceeds 25 to block 212 to determine if a nag has been set, which flag indicates that O 92~09899 t ~ PCT/US91/09000 another portion of the display needs to be written. Only one portion of the display is written at a time. If other portions of the display have not been written, then the display is still in progress. If another display portion needs to be written, flow proceeds from block 212 to block 214 where the 5 microcontroller updates the display using conventional line-by-line LCD
writing techniques. From block 214, flow proceeds to block 216 where the microcontroller performs a return from subroutine command.
From block 212, flow proceeds to block 218 if a display update is not in progress to determine if the key-ready flag is set (see block 208 of 10 FIG. 6). If the key-ready flag is set, then a key or switch was detected as being depressed and released, and flow proceeds to block 220.
If the key-ready flag 2s not set, flow proceeds from block 218 to block 2æ where the microcontroller performs a test to determine if current-related information is being displayed; for example, the display of 15 current in each of the three phases and ground fault.
If the display is not displaying current-related information, flow proceeds from block 222 to block 224 where the microcontroller performs a test to determine if the display is displaying configuration information and the configuration requires changing. If at least one of these conditions 20 is not met, no further action is necessary and 90w proceeds to b]ock 216 for exiting the subroutine. If both of these conditions are met, flow proceeds from block 224 to block 226 where the microcontroller sets up for writing the new configuration. This may be done by writing a portion of the new display during this visit to the display service routine and the WO 92/09899 15 2 ~ 7 ,~, ~t !~
remaining portion during the next visit. From block 226, flow proceeds to block 214 for writing the new configuration data on the display.
~ rom block 222, flow proceeds to block 228 if the information bein~
displayed is current-related information. At block 22~, the current-related S information is set for being updated (or refreshed) by setting a flag to record that updates should only pertain to the numbers, e.g., the displayed amperages for the various phases and ground fault. This updating or refreshing in the display mode for "current" is set to occur every 500 milliseconds. From block 228, flow proceeds to block 214 for the actua]
10 refreshing of the current-related information on the display.
At block 220, if the push-button switch corresponding to a function key is detected as being depressed and released, flow proceeds to block 232 where the microcomputer toggles the display from the configuration-type display to the current-related information display or vice-versa. From 15 block 232, flow proceeds to block 214 where the display is actually written to for the change indication of block 232.
From block 220, flow proceeds to block 233 if the function switch was not engaged. At block 233, a test is performed to determine if current-related information is being displayed. If so, en~agement of the 2û other switch, which activated the key ready flag, was improper and flow proceeds to block 216. From block 233, flow proceeds to block 236 if the microcontroller determines that the display is not displayin~ current-related information.
At this point, the microcontroller has determined that a switch was 25 depressed and released (block 218) and that it was not the "function"
?J~r~ J~ 16 PCI/US91/09000 switch (block 22~). Since the only other switch is the "select" switch, the microcontroller deduces that the "select" switch has been depressed and released. The "select" switch is engaged by the user when it is desired to switch to the next of the six submodes of the configuration mode. If the 5 last of the six submodes is displayed when the "select" switch is en~aged, a transition to the first submode is displayed. From block 236, flow proceeds to blocks 232 and 214 to chan~e the display.
While the invention has been particularly shown and described with reference to a particular embodiment, various modifications may be made.
10 For example, the microcontroller (or microcomputer) 18 of FIG. la may be implemented using discrete circuits. Further, rather than reactivating power solely by the switch 50 of FIG. la, power may be continuously provided from the battery to a data sensing circuit, such as the interface circuit 16 of FIG. la, so that the data sensing circuit momentarily forward 15 biases the diode 54 to initiate power to the device of FIG. 1. A
conventional "one-shot" circuit may "OR"-tied with the switch S0 to couple the data sensing circuit to the diode 54. It will be recognized by those skilled in ~he art that such modifications and changes may be made to the present invention described above without departing from the spirit and ~0 scope thereof.
- ` ;
,
Claims (20)
1. A communication device for communicating with a circuit breaker trip unit, comprising:
a keypad;
a display;
interface means for coupling data sent from the trip unit with the communication device;
a control circuit, responsive to the keypad and to the data sent from the trip unit, for controlling the display;
a local power source which provides power to the communication device; and a power switch, responsive to the control circuit, for disabling the power pack during periods when data is not being received from the trip unit.
a keypad;
a display;
interface means for coupling data sent from the trip unit with the communication device;
a control circuit, responsive to the keypad and to the data sent from the trip unit, for controlling the display;
a local power source which provides power to the communication device; and a power switch, responsive to the control circuit, for disabling the power pack during periods when data is not being received from the trip unit.
2. A communication device, according to claim 1, wherein the control circuit includes timing means for timing periods during which data is not received from the trip unit.
3. A communication device, according to claim 2, wherein the control circuit sends a signal to the power switch to disable the local power source when the timing means indicates that data has not been received from the trip unit for a prescribed period of time.
4. A communication device, according to claim 1, wherein the keypad includes a plurality of momentary switches.
5. A communication device, according to claim 4, wherein the plurality of momentary switches includes a first switch to select one of a plurality of display modes and a second switch to select one of a plurality of submodes associated with one of said plurality of display modes.
6. A communication device, according to claim 1, wherein the control circuit includes a microcomputer which receives and interprets the data sent from the trip unit.
7. A communication device, according to claim 6, wherein the microcomputer controls the display by responding to the first and second switches.
8. A communication device, according to claim 1, further including a momentary switch which is used to initiate system power from the local power source.
9. A communication device, according to claim 8, wherein the control circuit includes means, responsive to the initiation of power, for maintaining and controlling the local power source after the momentary switch initiates power.
10. A portable communication device for communicating with a circuit breaker trip unit, comprising:
a keypad;
a display;
electrically isolated interface means for coupling data sent from the trip unit with the portable communication device;
a microcomputer circuit, which interprets signals received from the keypad and receives the data sent from the trip unit to control the display, and includes timing means for indicating when data has not been received from the trip unit for a prescribed period of time;
a local power source which provides power to the portable communication device independently of power provided to the trip unit;
and a power switch, coupled to the microcomputer circuit, configured to disable the local power source in response to the timing means indicating that data has not been received from the trip unit for the prescribed period of time.
a keypad;
a display;
electrically isolated interface means for coupling data sent from the trip unit with the portable communication device;
a microcomputer circuit, which interprets signals received from the keypad and receives the data sent from the trip unit to control the display, and includes timing means for indicating when data has not been received from the trip unit for a prescribed period of time;
a local power source which provides power to the portable communication device independently of power provided to the trip unit;
and a power switch, coupled to the microcomputer circuit, configured to disable the local power source in response to the timing means indicating that data has not been received from the trip unit for the prescribed period of time.
11. A portable communication device, according to claim 10, wherein the electrically isolated interface means includes an optical isolator.
12. A portable communication device, according to claim 10, wherein the microcomputer circuit commands the power switch to shut down the local power source after the prescribed period of time.
13. A portable communication device, according to claim 10, wherein the keypad includes a plurality of momentary switches.
14. A portable communication device, according to claim 13, wherein the plurality of momentary switches includes a first switch to select one of a plurality of display modes and a second switch to select one of a plurality of submodes associated with one of said plurality of display modes.
15. A portable communication device, according to claim 14, further including a third momentary switch which is used to initiate system power from the local power source.
16. A portable communication device, according to claim 14, wherein the plurality of display modes includes a first mode associated with displaying currents monitored by the trip system.
17. A portable communication device, according to claim 14, wherein the microcomputer circuits controls the display by responding to the first and second switches.
18. A portable communication device, according to claim 10, wherein the microcomputer circuit includes means for maintaining and controlling the local power source.
19. A portable communication device, according to claim 10, wherein the timing means includes an interrupt driven timing program.
20. A portable communication device for communicating with a circuit breaker trip unit, comprising:
a manually operable power-up switch for initiating power to the device;
a first push-button switch which is engaged to select one of at least two display modes and a second push-button switch which is engaged to select one of at least two display submodes;
a display;
an optical waveguide for coupling data sent from the trip unit with the portable communication device;
a microcomputer circuit, which interprets signals received from the keypad and receives the data sent from the trip unit to control the display, and including timing means for indicating when data has not been received from the trip unit for a prescribed period of time;
a local power source which provides power to the portable communication device independently of power provided to the trip unit;
and a power switch, coupled to the microcomputer circuit, configured to disable the local power source;
wherein the microcomputer circuit commands the power switch to disable the local power source in response to the timing means indicating that data has not been received from the trip unit for the prescribed period of time.
a manually operable power-up switch for initiating power to the device;
a first push-button switch which is engaged to select one of at least two display modes and a second push-button switch which is engaged to select one of at least two display submodes;
a display;
an optical waveguide for coupling data sent from the trip unit with the portable communication device;
a microcomputer circuit, which interprets signals received from the keypad and receives the data sent from the trip unit to control the display, and including timing means for indicating when data has not been received from the trip unit for a prescribed period of time;
a local power source which provides power to the portable communication device independently of power provided to the trip unit;
and a power switch, coupled to the microcomputer circuit, configured to disable the local power source;
wherein the microcomputer circuit commands the power switch to disable the local power source in response to the timing means indicating that data has not been received from the trip unit for the prescribed period of time.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US620,510 | 1984-06-14 | ||
| US62051090A | 1990-11-30 | 1990-11-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2074264A1 true CA2074264A1 (en) | 1992-05-31 |
Family
ID=24486253
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2074264 Abandoned CA2074264A1 (en) | 1990-11-30 | 1991-11-27 | Display for a circuit breaker trip unit |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0513319A4 (en) |
| AU (1) | AU9102191A (en) |
| CA (1) | CA2074264A1 (en) |
| MX (1) | MX9102320A (en) |
| WO (1) | WO1992009899A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06217449A (en) * | 1992-10-27 | 1994-08-05 | Westinghouse Electric Corp <We> | Overcurrent protective device with programmable communication and action stop function |
| GB2288293B (en) * | 1994-04-08 | 1998-12-16 | Gen Electric | Circuit interrupter |
| US8032260B2 (en) | 2005-11-30 | 2011-10-04 | General Electric Company | Method and system for controlling a power distribution system |
| US20070159746A1 (en) | 2005-12-30 | 2007-07-12 | General Electric Company | Centrally controlled protection systems having reduced energy let-through mode |
| US8018092B2 (en) | 2008-04-15 | 2011-09-13 | General Electric Company | System and method for managing power supply to a circuit breaker control unit |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4285043A (en) * | 1976-09-21 | 1981-08-18 | Sharp Kabushiki Kaisha | Power transmission controller for electronic calculators |
| US4377836A (en) * | 1980-04-15 | 1983-03-22 | Westinghouse Electric Corp. | Circuit interrupter with solid state digital trip unit and positive power-up feature |
| US4535409A (en) * | 1981-09-18 | 1985-08-13 | Mcgraw-Edison Company | Microprocessor based recloser control |
| US4977513A (en) * | 1984-08-20 | 1990-12-11 | Power Solutions, Inc. | Circuit breaker current monitoring |
| US4631625A (en) * | 1984-09-27 | 1986-12-23 | Siemens Energy & Automation, Inc. | Microprocessor controlled circuit breaker trip unit |
| FR2578090B1 (en) * | 1985-02-25 | 1989-12-01 | Merlin Gerin | CIRCUIT BREAKER WITH DIGITAL STATIC TRIGGER WITH REVERSE TIME TRIGGERING FUNCTION |
| FR2592737B1 (en) * | 1986-01-03 | 1988-03-18 | Merlin Gerin | READER FOR A DIGITAL TRIGGER ASSOCIATED WITH A POWER CUT-OFF APPARATUS |
| US4827369A (en) * | 1987-02-20 | 1989-05-02 | Westinghouse Electric Corp. | Circuit interrupter apparatus with a selectable display means |
| US4996646A (en) * | 1988-03-31 | 1991-02-26 | Square D Company | Microprocessor-controlled circuit breaker and system |
| US4870531A (en) * | 1988-08-15 | 1989-09-26 | General Electric Company | Circuit breaker with removable display and keypad |
-
1991
- 1991-11-27 AU AU91021/91A patent/AU9102191A/en not_active Abandoned
- 1991-11-27 WO PCT/US1991/009000 patent/WO1992009899A1/en not_active Application Discontinuation
- 1991-11-27 CA CA 2074264 patent/CA2074264A1/en not_active Abandoned
- 1991-11-27 EP EP19920901374 patent/EP0513319A4/en not_active Withdrawn
- 1991-11-29 MX MX9102320A patent/MX9102320A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| WO1992009899A1 (en) | 1992-06-11 |
| EP0513319A4 (en) | 1993-12-22 |
| MX9102320A (en) | 1992-09-01 |
| AU9102191A (en) | 1992-06-25 |
| EP0513319A1 (en) | 1992-11-19 |
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