JP2919939B2 - Interlocking device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interlocking device for controlling a traffic light and a switch of a railroad transportation.

[Conventional technology]

Traffic lights, switches, and the like in railway station premises and the like have characteristics as security devices. Therefore, it is necessary to provide a so-called fail-safe property so that when these devices fail, they always fail on the safe side (for example, in the case of a traffic light, a stop signal is used).

Therefore, when controlling a traffic light and a switch, a relay is used to perform control while giving a chain relationship between these devices or between these devices and the progress of the train. Conventionally, a relay interlocking device in which logic is configured has been used.

In other words, the relay interlocking device means that the signal staff at the station sets the entrance route of the line set on the schedule for the approaching train, or departs the train from the predetermined line at the time of the schedule It is a device for controlling a traffic light and a switch in response to a course setting operation for setting a departure course to be performed. In this way, by interlocking these devices, a state in which the train can run safely is ensured, and thereafter control is performed so that the train is allowed to enter.

Hereinafter, based on FIGS. 5 and 6 (a) to (g),
The configuration and operation of a conventional relay interlocking device will be described.
However, the conventional relay interlocking device is composed of a plurality of circuits having a large number of coils and contacts and the like. The description is complicated. On the other hand, in order to understand the contents of the present invention, a detailed description is not necessarily required for all of these conventional techniques.

Therefore, in the following description, explanations and illustrations of portions considered unnecessary are partially omitted. The description of terms and the manner of illustration and the like are almost the same as those described in "Signal Primer" (incorporated association: Signal Security Association, issued on June 25, 1988).

FIG. 5 shows an interlocking chart of the station A having a main line of the first line (main line) and a sub-main line of the second line (middle line).

On the premises of station A, there is a main line traffic signal 1L and a sub-main line traffic signal 2L. An electric switch 41 is installed. And the track circuit 41T is provided in the installation section of the switch 41,
In the section outside the track circuit, the track circuit descends 1T,
Track circuits 1LT and 2LT are provided in the inner section, respectively.

To explain each column in this interlocking chart, first, in the 1L course, 41T, 1L in the "Signal control or check lock" column
T is a traffic light 1L when there are no trains in these track circuit sections.
Means that it is allowed to issue an entry permission signal. Also, 41 in the “Lock” column means that when the switch 41 is controlled to the normal position, after setting the 1L course, the lock of the switch 41 is performed. (41)
T) is a switch 41 when the train is in the track circuit 41T section.
Is locked and unlocked after passing through the track circuit 41T. Then, go down 1T in the “approaching lock or pending lock” column. Means that if there is a train in the down 1T section, the course is maintained for 90 seconds even if the 1L lever is returned to the normal position. In addition, about 1L lever and 2L lever position,
"Localization" corresponds to a state in which entry into these paths is prohibited (red light), and "inversion" is a state in which entry into these paths is permitted (blue light). Corresponding.

Each of the circuits shown in FIGS. 6A to 6G controls the switch 41 and the traffic lights 1L and 2L so as to satisfy the conditions of the interlocking chart.

 The meanings of the symbols in these figures are as follows.

FIG. 6A shows a lever relay circuit. When the lever 1L is tilted to the opposite side, the coil is excited and the relay 1LR is turned on.

FIG. 6B shows an approach lock relay circuit. At all times,
Relays 1LHR, 2LHR, 1LR, 2LR drop and these b contacts, Is closed, and a contact of relay 1AR (ON when there is no train on section 1T) Is closed, the approach lock relay 1LASR is on.

When the 1L lever is tilted to the opposite side to make the train enter the main line, the relay 1LR turns on and contacts Opens. At this time, the switch 41 is in the orientation, Is also open, the approach lock 1 LASR is turned off (switching of the switch 41 is disabled and a train can enter). When the course is further configured and the relay 1LHR (see FIG. 6 (f)) is turned on, the contact The circuit of the access lock relay 1LASR is opened at two places.

Next, when the train enters section 41T, relay 1LHR turns off and the contact Closes, and contacts return when the 1L lever is returned to the normal position to prohibit the entry of the following train Is closed, the approach lock relay 1LASR is turned on again.

However, before the train has yet entered section 41T, the signal staff once placed the 1L lever in the opposite position (entry permitted) when it has already entered section 1T, and then localizes (entry prohibited) ) May be performed. In such a case, if the switch 41 performs the switching operation in response to the 1L lever operation as it is, a very dangerous state occurs. Therefore, the train is already down 1T
Even if the 1L lever is returned to the normal position after entering the vehicle, the circuit configuration is such that the switch 41 does not perform the switching operation until 90 seconds have elapsed.

That is, after the train enters the section down 1T and section 41T
If the 1L lever that has been inverted is returned to the normal position before entering the relay, the relay 1LHR (Fig. 6 (f)) falls and contacts Closes, Circuit is connected. However, at this time, the contact Is open (there is a
1AR is OFF), and the approach lock relay 1LASR is not ON.

But at this time Relay 1LMSlR is turned on in the circuit of This excites the relay 90TEUR (see FIG. 6 (c)). The relay 90TEUR is an on-delay relay that turns on after 90 seconds. Is closed and relay 90TENR is turned on. Therefore, Circuit is connected, and the approach lock relay 1LASR is turned on.

In other words, if the train returns to the normal position after the train enters the section down 1T, the approach lock relay 1LAS
R will turn on. Note that the time of “90 seconds” is a time sufficient for stopping when the traffic light 1L becomes a red light and the train is braked, and is a time defined by the standard.

FIG. 6 (c) shows a path locking relay circuit, which is a relay 90.
The operation of the TEUR and the like is as described above with reference to FIG. 6 (b).

Also, after the above 90 seconds have passed, the relay 41TLSR
R turns on No train on section 41T It is a relay that turns on only when. As described below, the switching of the switch 41 is performed by the relay 41TLSR so as not to cause danger to the running of the train. In addition, Are connected in parallel and are self-holding,
This is the point where the train enters section 41T from the opposite path and contacts Is considered to open.

FIG. 6D shows a point control relay circuit. When the relay 41TLSR is turned on and there is no train in the section 41T, the relay 41WLR and the relay 41W are excited.

When a current flows from the left side of this figure, the switch 41 is in the localization position (90 °), and when a current flows from the right side, the switch 41 is in the reverse position (45 °). So that
The point drive motor is controlled. (See FIG. 6 (e)). The relay 41W is a magnetic holding relay, and retains its state even when the current is cut off.

In addition, Is a switching lever used when the switching device 41 is directly switched manually, but is not directly related to the contents of the present invention, and therefore the description is omitted.

FIG. 6 (e) shows a point relay circuit. relay
41KR is a relay that is turned on and off by a circuit controller linked to the operating position of the switch 41.

When the switch 41 is in the normal position, the relay
The relay 41KRPR is turned on when the 41KNPR is turned on and the switch 41 is in the reverse position.

FIG. 6 (f) shows a signal display relay circuit. Relay 1L
HR has no train in section 41T , Approaching locked The pathway lock is locked The point relay is locked. Pointer 41 has been localized and there is no train in section 1LT 1L lever is inverted Sometimes a relay that is turned on.

When relay 1LHR is turned on, its contact Closes and contacts Is open, so the relay 5LHR (not shown, turns on when the signal in the forward section 5LT of section 1LT is the entry permission signal) The green light (G) lights when is closed. Forward section
When the signal of 5LT is the stop signal, relay 5LHR
Drops and contacts Is closed, the yellow signal (Y) is turned on.

FIG. 6 (g) shows a track relay circuit. When there is no train in section 41T, coil 41 connected to the track in this section
TR (not shown) is excited and contacts Is closed and 41TPR is turned on.

Similarly, when there is no train in section 1LT, Is closed, relay 1LTPR is turned on.

6 (a) to 6 (g), the control of the switch 41 and the traffic lights 1L and 2L are performed so as to satisfy the conditions of the interlocking chart of FIG. .

[Problems to be solved by the invention]

As described above, the conventional relay interlocking device uses a plurality of circuits and configures logic with relays.

However, since the number of contacts per relay is limited, the number of relays used is very large. As a result, not only the device becomes large, but also the number of accidents such as poor contact of the relay or disconnection of the coil increases, resulting in an increase in maintenance costs.

Further, since the operation speed of the relay is slower than that of a semiconductor switch or the like, there may be a problem that the circuit is opened momentarily during operation. When the number of relays is large, it is necessary to take measures to prevent a malfunction or a malfunction caused by such an instantaneous opening, but the circuit becomes more complicated.

Therefore, in order to eliminate such a drawback caused by using a relay circuit, recently, an electronic interlocking device which performs interlocking by forming a logic by a microcomputer has been commercialized.

However, the interlocking logic in this electronic interlocking device also ultimately inherits the above-described concept of the conventional relay interlocking device, and has a disadvantage that a program becomes complicated and software cost becomes extremely high. Was something.

The present invention has been made in view of such circumstances, and it is an object of the present invention to simplify the circuit configuration to simplify the interlocking logic, thereby eliminating both disadvantages of the conventional relay interlocking device and the electronic interlocking device. It is assumed that.

[Means for solving the problem]

According to the present invention, as a means for solving the above problems, a traffic light and a switch are installed in the course of a train, and the train enters a predetermined inner track by controlling the light switch and the traffic light. In the interlocking apparatus, when the train enters the predetermined route, a lever switch means for outputting an entry instruction signal by operating the entry instruction side and outputting an entry inhibition signal by operating the entry inhibition side; A signal control means for outputting a train absent signal when no train is present in a section near the location where the lever and the traffic light are installed; and a conflict when a route competing with the predetermined route is not taken. Competitive track check means for outputting a track non-existence signal, a switch check means for outputting a track direction match signal only when the switch is in a predetermined track direction, and If there is a train, check that there is no train in the section where the indicated route must be maintained until the train disappears, and if there is no train, a train absence signal Route locking means for outputting a train, and if the train is present, whether or not a train is present in a section where the designated route must be held at least until a predetermined time has elapsed. Whether it is not present, outputs a train non-existence signal immediately when it is not present, and when it is present, approaches lock control means for outputting a time lapse signal after a lapse of a predetermined time; output of an entry instruction signal by the lever switch means; An output of a train absence signal by the signal control means, an output of a competition path absence signal by the competition path check means, Only when the output of the traveling direction match signal by click means is performed every,
An entry permission signal is input to the set side, while an output of an entry prohibition signal by the lever switch means, an output of a train absence signal by the track locking means, a train absence signal by the approach locking control means, or time lapse. Only when all of the signals have been output, an entry permission release signal is input to the reset side, and this entry permission signal is held unless the input permission release signal is input. Means, and if the switch is not oriented in the predetermined course, there is no train in the section where the switch must be locked if a train is present Only when the access permission signal holding unit is in a reset state, the control unit controls the pointer to be in a predetermined course direction. Depending on the state of the signal holding permission signal holding means, it is a structure in which to carry out the control of the switch with and the traffic.

(Operation) In the above configuration, the entry permission signal is input to the entry permission signal holding means when the lever switch corresponding to the designated path is operated to the entry instruction side, and the signal control means If all of the conditions are satisfied, such as confirming that there is no existing route, the competing course checking means confirming that no competing course has been taken, and the point checking means checking the correct direction of the point. It is.

Also, the entry permission release signal is input to the entry permission signal holding means when the lever switch once operated to the entry instruction side is operated to the entry prohibition side, and the track locking means detects the absence of the train. This is the case where all of the conditions are satisfied, such as confirming that the approach lock control means confirms the absence of a train or confirming that a predetermined time has elapsed.

The switch and the traffic signal are controlled in accordance with the signal holding state of the entry permission signal holding means.

As described above, the entry permission signal holding means for inputting the entry permission signal, that is, the set signal, and for inputting the entry permission release signal, that is, the reset signal, is a means having a so-called flip-flop function.

Generally, when a means having a flip-flop function is used, a circuit on the set signal side and a circuit on the reset signal side are separated. In the past, fail-safeness was maintained by acting on the safe side when there is no signal,
When a flip-flop circuit is used, even if there is no signal, it is not always safe. Therefore, adoption of a means having a flip-flop function in an interlocking device has not been considered.

However, by effectively utilizing the advantage of the flip-flop function, that is, the function of holding the set state until the reset signal is input and the reset state is reached, the circuit configuration is significantly simplified.

On the other hand, even if a means having a flip-flop function is adopted, it is sufficiently possible to satisfy the fail-safe requirement by other measures in the current state of the art.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 4.

FIG. 1 is a block diagram showing a general configuration of an embodiment of the present invention. In this figure, reference numeral 101 denotes an a contact that closes when the lever m (see FIG. 113) is tilted to the approach instructing side, that is, the opposite side. When the contact point 101 is closed, the signal control means 102 checks that there is no train in the section near the place where the traffic light and the switch are installed. It is checked that the route competing with the route is excluded.

The switch checking means 104 checks whether or not the direction of the switch is in the specified course direction, and outputs an entry permission signal only when the switch is in the specified direction.

107 is an entry permission signal holding unit that inputs an entry permission signal to the set side and inputs an entry permission release signal to the reset side, and is configured by a magnetic holding relay mSR having a flip-flop function.

Further, even if the contact point 101 is once closed and then opened (when the lever switch is once tilted to the opposite side and then returned to the localization side), the track locking means 108 indicates that the train exists in the predetermined section. If this is the case, it is a means to keep the course unchanged until this train is gone.

Reference numeral 109 denotes a slow-release relay (off-delay) circuit for preventing the course from being changed until a predetermined time has elapsed even if there is no train from the predetermined section. This slow release relay circuit 109 is a circuit necessary when taking the course 2L. Therefore, in the circuit of FIG. 3 described later, a circuit corresponding to the slow release relay circuit 109 is not added, whereas in the circuit of FIG.
A circuit equivalent to 109 is added.

Reference numeral 110 denotes an approach lock control means, which is formed by an approach lock circuit 111 and a slow release relay circuit 112. The approach lock control means 110 checks whether or not a train exists in a predetermined section, and if it does not exist, immediately outputs an entry permission release signal to the entry permission signal holding means 107. In this case, the access permission signal is output to the access permission signal holding means 107 after a predetermined time has elapsed.

Signal control relay mHR is contact , A signal from the switch checking means 104 is inputted. 113 such as a signal display relay circuit,
A circuit is configured using the contacts of the relay mHR.

The switch control means 106 is provided with a check locking means 105 and a contact point. When the switch 41 is not in the predetermined course, the switch 41 is controlled so as to be in the predetermined course.

FIG. 2 is a circuit diagram showing the configuration of the slow release relay circuits 109 and 112 and the signal display relay circuit 113 in FIG.
In FIGS. 1 and 2, m, mTTlR, mTlR, etc., corresponds to this code for each signal, and in FIG. 3, 1L is a code corresponding to m, and FIG. In case 2L is m
Is obtained.

Is the b contact of the track circuit relay that unlocks time when the course is 2L. Also, the contacts in the signal relay 113 shown in FIG. Is an a-contact of a relay that may display a progress signal for the train.

Next, a specific configuration of FIG. 1 will be described with reference to FIGS. FIG. 3 shows a circuit used when the train is to enter the down main line (see the track circuit in FIG. 5), that is, the main line side, and FIG. 4 shows the train entering the middle line, that is, the sub main line side. It shows a circuit used in the case.

First, in FIG. 3, when the 1L lever switch of the line 201 is turned to the opposite side, the relay 1LR is turned on, and the contact of the line 202 is turned on. Closes. At this time, if there is no train in section 41T, 1LT, these contacts Is closed. If the path of 2L, which is the competition path of 1L, is not taken, the relay 2LSR (see Fig. 4) is off, so the contact Is closed. If the orientation of the switch 41 is the localization side (main line side) from the beginning, its contact Is closed. As a result, the line 202 becomes conductive, and the set signal is input to the relay 1LSR.

If the direction of the switch 41 is on the opposite side (sub main line side), Is closed, the relay 41NR is turned on. Relay 41
NR is for switching the switch 41 from the reverse side to the localization side. When the switch 41 is switched to the localization side by the relay 41NR, the contact Closes. Therefore, the line 202 becomes conductive,
The set signal is input to the relay 1LSR.

The fact that the set signal is input to the relay 1LSR and turned on means that the route setting in the 1L direction for the train has been completed. Also contact Is closed, relay 1LHR is turned on. Then, when the relay 1LHR is turned on, the contact of the line 205 Is closed, the relays 1L-G are turned on, and the green signal is turned on. At this time, contact Are opened, so that the relay 1L-R for the red signal is not turned on.

Next, when the train advances due to the lighting of the green light and the train enters section 41T, the contact point of line 202 Is opened, the relay 1LHR falls. And line 20
5 contacts Opens and contacts Is closed, the green light turns off and the red light turns on.

At this time, the line 202 is open, but the relay 1LS
Since R is a magnetic holding relay, even if the set signal is not input, it keeps on unless the reset signal is input. If relay 1LSR is ON, contact of line 204 Is closed. Therefore, as long as the 1L lever is on the opposite side Relay 1LTlR is on, contact on line 203 Is open.

Next, when the train proceeds further and passes the section 41T, the signalist returns the 1L lever from the opposite side to the localization side.

Then, the contact of line 203 Is closed and line 203 is conducted (contact Contact down Is closed), the relay 1LSR is turned off by the input of the reset signal.

When relay 1LSR turns off, contact on line 202 Opens (at this time, the 1L lever is returned, so the contacts Is also open), so that the light off of the green light and the light off of the red light are connected as they are.

Here, in the same manner as described in the conventional example, when the signal staff has once tilted the 1L lever to the opposite side and then returned to the localization side again, when the train has already entered the section down 1T The operation will be described.

When the 1L lever is returned to the stereotaxic position, Is also closed (the train has not yet entered section 41T)
But contact down Is open. But, Are connected in parallel, so if this contact Is closed, this contact , The reset signal is immediately sent to the relay 1LSR.

However, the relay 1LTlR on the line 204 is an off-delay relay, and the contact Even if is opened and is not excited, the off operation is not performed until 90 seconds have elapsed. Therefore, the contact of line 203 Has been open for 90 seconds and already 1T down
The route of the train approaching is maintained as it is. And after 90 seconds, the contact Is closed and relay 1LSR is reset, but at this point,
The train should have passed section 41T or stopped.

The above is the main operation of FIG. 3, but the operation in the case of FIG. 4 is almost the same, and therefore the detailed description is omitted.

However, in FIG. 4, a line 303 not shown in FIG.
Contacts And the circuit of line 306 has been added, which will be described briefly.

In Fig. 4, when the train has passed section 41T, 2L
The case where the lever is returned to the localization side is also considered.

In other words, if the train exists in section 41T, line 3
06 contacts Is closed, relay 2LTTTlR is turned on, and the contact Is open.

Then, when the train passes through section 41T, the contact point of line 306 Opens, and the relay 2LTTlR is not excited. However, since this relay 2LTTTlR is an off-delay relay, Does not close immediately, but will close 30 seconds after the train passes section 41T. This allows the relay
2 LSR is reset.

As described above, the configurations shown in FIGS. 3 and 4 use the relays 1LSR and 2LSR having the flip-flop function, and therefore have a very simple circuit configuration as compared with the conventional device. Therefore, it is possible to eliminate or greatly reduce all the drawbacks of the conventional device, such as an increase in the size of the device, an increase in maintenance costs, and a malfunction due to an instantaneous opening of the circuit.

However, in the present invention, the point that the fail-safe property is secured while using the flip-flop circuit or the like is not mentioned in the above description. However, at the current technical level, it is relatively easy to secure sufficient fail-safe properties by multiplexing and the like.

The circuits shown in FIGS. 3 and 4 are embodiments in the case where the circuits are constituted by relays.

However, as mentioned at the outset, relays require troublesome maintenance due to failures such as poor contact and mechanical stiffness and problems such as life span. I have.

However, there is a disadvantage in that if the interlocking function is to be created by software using a microcomputer, the software production cost increases.

On the other hand, the present invention is a relay logic, and there is a programmable controller (PC) as a computer which digitizes this.

Then, when the relay circuit shown here is input to the PC, if the input is performed by replacing the ladder circuit with the relay circuit, the interlocking device can be realized as the PC. Of course, the relay element of the PC can use the timer function and the flip-flop function, so that all the relay logic circuits shown in the present invention can be realized by the PC.

Regarding the fail-safe operation in this case, it is assumed that the function is achieved by completely different methods such as multiplexing and readback, but the description thereof is omitted.

In the above-described embodiment, the magnetic holding relays 1LSR and 2LSR are used as the entry permission signal holding means. However, an electronic circuit using an element such as a transistor may be used as long as it has a flip-flop function. Good.

In the above embodiment, the so-called course lever-type interlocking device has been described, but the present invention is not limited to this.
The present invention is also applicable to a course selection type interlocking device.
In other words, the "lever switch" of the present invention can be interpreted as including both the "lever lever" provided at the beginning of the path and the "selection push button" provided at the end in the path selection-type interlocking device. .

Further, although the present invention is mainly intended for use in controlling the route of a railway, the present invention can also be applied to controlling the route of a vehicle traveling on a track laid on a site such as a factory or an amusement park. It is possible.

In the present invention, only a case where a switch is provided on the way is described, and a simpler case where no switch is provided is not described. However, it will be apparent that the circuit configuration can be further simplified by using the technical idea of the present invention even when no switch is provided.

〔The invention's effect〕

As described above, according to the present invention, because of its commitment to fail-safe, it has not been used conventionally.
Since the configuration having the means having the flip-flop function is positively used, the circuit configuration can be simplified and the interlocking logic can be simplified.

Therefore, as compared with the conventional device, the device can be downsized, the maintenance cost can be reduced, and no countermeasure for preventing a malfunction or the like due to an instantaneous opening of the circuit is required.

And even if it is going to perform interlocking by a microcomputer, since an interlocking logic is simple, a program becomes simple and software cost can be reduced sharply.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.
FIG. 1 is a partial circuit diagram of some components in FIG. 1, FIGS. 3 and 4 are circuit diagrams according to embodiments embodying the block diagram of FIG. 1, and FIG. FIGS. 6 (a) to 6 (g) are circuit diagrams showing the configuration of each relay circuit used in the conventional example. 1L, 2L …… Signal, 41 …… Pointer, 1T, 41T, 1LT, 2LT…
... section, 101 ... lever switch, 102 ... signal control means,
103: Competitive path check means, 104: Pointer check means, 106: Pointer control means, 107: Entry permission signal holding means, 108: Path locking means, 110: Approaching chain Lock control means.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-185857 (JP, A) JP-A-48-69207 (JP, A) JP-A-53-87507 (JP, U) JP-B-46 35323 (JP, B1) (58) Field surveyed (Int. Cl. ⁶ , DB name) B61L 19/00-19/16

Claims (1)

(57) [Claims] An interlocking device for installing a traffic light and a switch in the course of a train and controlling the switch and the traffic light to cause the train to enter an inner predetermined route. When entering the predetermined course, a lever switch means for outputting an entry instruction signal by operation to the entry instruction side and outputting an entry inhibition signal by operation to the entry inhibition side, and the switch and the traffic light are installed. Signal control means for outputting a train non-existence signal when a train does not exist in a nearby section, and a competition for outputting a competition course non-existence signal when a course competing with the predetermined course is not taken. Track check means, a switch check means for outputting a track direction coincidence signal only when the switch is in a predetermined track direction, and when the train is present, Track locking means for checking that no train exists in the section where the designated route must be held until the car disappears, and outputting a train absence signal only when there is no train. And, if the train is present, it is checked whether or not the train exists in the section where the designated route must be held at least until a predetermined time has elapsed, and the train does not exist. An approach lock control means for immediately outputting a train non-existence signal, and outputting a time lapse signal after a lapse of a predetermined time when it is present; outputting an entry instruction signal by the lever switch means; An output of a presence signal, an output of a non-existence signal of a competitive route by the competitive route check means, Only when all of the outputs have been performed, an entry permission signal is input to the set side, while an output of an entry prohibition signal by the lever switch means, an output of a train non-existence signal by the track locking means, and an approach chain Only when all of the train absence signal or the time lapse signal has been output by the lock control means, an entry permission release signal is input to the reset side, and this entry permission signal is maintained unless this entry permission release signal is input Entry permission signal holding means adapted to be operated, and when the switch is not oriented in a predetermined course,
If there is no train in the section where the point must be locked if the train is present, and only if the access permission signal holding means is in a reset state. A switch control means for controlling the switch to be oriented in a predetermined course, and the switch and the traffic light according to a signal holding state of the access permission signal holding means. An interlocking device characterized in that the interlocking device is controlled.