JP3103423B2 - Load control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load control device for controlling a plurality of loads.

[0002]

FIG. 4 is a circuit diagram showing a schematic configuration of a conventional load control device 11. As shown in FIG. The load control device 11 includes terminals T11 and T12 for connecting external devices such as a power supply P11 and loads L11 and L12 and a common terminal Tca, and relay contacts 13a and 14a and relay contacts 13a and 14a.
switching elements 13 and 14 implemented by relays composed of coils 13b and 14b for opening and closing a, and a transistor TR1 for controlling the operation of the switching elements 13 and 14
1, TR12, input resistors R11a, R11b, R12a, R12b of the transistors TR11, TR12, and a signal control circuit 12 for controlling the transistors TR11, TR12. One end of each of the coils 13b and 14b of the switching elements 13 and 14 is supplied with a predetermined voltage from a power supply circuit 15 through a power supply line Va, and is connected to a surge absorbing diode D in parallel with the coils 13b and 14b.
11, D12 are connected.

The signal control circuit 12 is realized by, for example, a memory for storing a control program and data, and a central processing unit for executing input / output of signals in accordance with the control program. The signal control circuit 12 sets the signal S12 to H
(High level), the transistor TR12 conducts, a current flows through the coil 14b, and the relay contact 14a closes, so that the relay contact 14a, the terminal T12, the load L12, the power supply P11, the common terminal Tca, the relay contact 1
A closed loop of the load circuit constituted by 4a is formed, a current determined by the output voltage of the power supply P11 and the impedance of the load L12 flows, and the load L12 operates. Similarly, when the signal S11 becomes H and the switching element 13 operates, a closed loop including the load L11 is formed, and the load L11 operates.

[0004]

However, in the conventional load control device 11 described above, the power supply P11 and the load L1
After connecting external devices such as L1 and L12 to the terminals T11 and T12 and the common terminal Tca, it is determined whether or not a closed loop of the load circuit is surely formed in response to the signals S11 and S12 of the signal control circuit 12, particularly, for each load. L11 and L12 are terminals T
There is a problem that it is not possible to easily confirm whether or not each of the switching elements 13 and 14 is operating normally, whether or not the switching elements 11 and T12 are normally connected. for that reason,
Check the continuity using a measuring instrument such as a tester,
Alternatively, the operation state is checked by actually driving the load, and the connection state of the external device is checked.As the number of connected loads increases, the operation becomes complicated, and all normal connections are checked. Has a problem that a large amount of time and work is required.

Further, before the signal control circuit 12 is operated to start controlling the loads L11 and L12, the relay contacts 13a,
Even if 14a is constantly short-circuited or interrupted, the failure cannot be easily confirmed, and a serious accident may occur during the execution of load control.

SUMMARY OF THE INVENTION An object of the present invention is to easily and quickly confirm that a wiring loop including a power supply and a plurality of load circuits in which a load and a switching element are connected in series and a power supply are normally formed. To provide a load control device that can perform the load control.

[0007]

According to the present invention, a plurality of load circuits in which a load and a first switching element are connected in series are provided.
In a load control device connected to a power supply through a common line, a second switching element inserted in the common line, current detection means connected in parallel with the second switching element, and a parallel connection with the second switching element And a limiting resistor element connected in series with the current detecting means for limiting the current so that the load does not operate. The second switching element is cut off, and the first switching element is sequentially turned on to reduce the load. A load control device for confirming a wiring connection state of a circuit.

[0008]

According to the present invention, in a load control device in which a plurality of load circuits in which a load and a first switching element are connected in series are connected to a power supply through a common line, a second switching element is connected to the common line. The second switching element is cut off because the current detecting means is connected in parallel with the second switching element and the limiting resistance element is connected in parallel with the current detecting means in parallel with the second switching element. When the first switching element is turned on in a state in which the load, the first switching element, the limiting resistor element, and the closed loop of the load circuit including the power supply are formed,
The presence or absence of a current flowing through the closed loop can be detected by the current detection means.

[0009]

FIG. 1 is a circuit diagram showing a schematic configuration of a load control device 1 according to an embodiment of the present invention.

The load control device 1 includes a power supply P1 and a load L1,
Terminals T1 and T2 and a common terminal Tc for connecting to external devices such as L2, and contacts 3a and 4a and contacts 3a and
Switching elements 3 and 4 realized by relays composed of coils 3b and 4b for opening and closing 4a, and transistors TR1 and TR2 for controlling the operations of switching elements 3 and 4
And the input resistances R1a, R1 of the transistors TR1, TR2.
1b, R2a, R2b and transistors TR1, TR2
And a switching element 31 inserted in a common line CL connected to a common terminal Tc.
And a transistor TRq for controlling the switching element 31, and input resistances Rqa and Rq of the transistor TRq.
qb, and a limiting resistor 22 and light emitting diodes 21a and 21b connected in parallel with the contact 31a of the switching element 31.
And a series circuit including a phototransistor 21c for receiving light emitted from the light emitting diodes 21a and 21b, a resistor Rp connected to the collector of the phototransistor 21c, and a light emitting diode Dp.

The coils 3b, 4 of the switching elements 3, 4
One end of b is supplied with a predetermined voltage from a power supply circuit 5 via a power supply line V, and diodes S1 and S2 for surge absorption are connected in parallel with the coils 3b and 4b.

The signal control circuit 2 is realized by, for example, a memory for storing a control program and data, and a central processing unit for executing input / output of signals in accordance with the control program. For example, when the signal S2 is set to H, the transistor TR2 is turned on, a current flows through the coil 4b, and the contact 4a is closed, so that the contact 4a, the terminal T2, the load L2, the power supply P1, the common terminal Tc , A closed loop of a load circuit composed of the common line CL and the contact 4a is formed, a current determined by the output voltage of the power supply P1 and the impedance of the load L2 flows, and the load L2 operates. Similarly, when the signal S1 becomes H and the switching element 3 operates, a closed loop including the load L1 is formed, and the load L1 operates.

FIG. 2 is a flowchart for explaining the operation for confirming the wiring connection state of the load circuit, and FIG. 3 is a timing chart of input / output signals of the signal control circuit.

First, starting from step a1, when the signal control circuit 2 sets the signal q1 to L (low level) at step a2 (time t1), the transistor TRq
Is not conducted, the current flowing through the coil 31b constituting the switching element 31 becomes 0, and the contact 31a is cut off.

Next, in step a3, when the signal control circuit 2 changes the signal S1 to H (time t2), the transistor TR1 is turned on, a current flows through the coil 3b constituting the switching element 3, and the contact 3a is turned on. State. Therefore, the contact 3a, the common line CL, the limiting resistor 22, the light emitting diode 21a or 21b, the common terminal Tc, the power supply P
1. When a closed loop of the load L1, the terminal T1, and the contact 3a is formed, the output voltage of the power supply P1, the impedance of the load L1, the current resistance of the limiting resistor 22, the light emitting diode 21
The current determined by the voltage drop of a flows through the closed loop, and the light emitting diode 21a emits light. When the current has the opposite polarity, the light emitting diode 21b emits light.

On the other hand, when the load L1 is not connected to the terminal T1 or when the contact 3a is not conducting due to a failure of the switching element 3, the above-mentioned closed loop is not formed and the light emitting diode 21a does not light.

When the phototransistor 21c receives light from the light emitting diodes 21a and 21b, the phototransistor 21c is turned on, the signal p1 is set to L, and the light emitting diode D is turned on.
p emits light.

Next, at step a4, the signal control circuit 2
Determines whether the level of the signal p1 is H or L. Signal p1
Is H, it is determined that the above-described closed loop has not been formed, and the routine goes to Step a99 for notifying the occurrence of an abnormality.
When the signal p1 is L, it is determined that the above-described closed loop has been formed, the signal S1 is set to L in step a5, and it is determined whether the level of the signal p1 is H or L in step a6. If the signal p1 is L, it is determined that the above-described closed loop is not resolved due to a steady short-circuit of the contact 3a or the like, and the process shifts to step a99 for notifying the occurrence of an abnormality. If the signal p1 is H, it is determined that the closed loop has been normally canceled, and the connection confirmation of the closed loop including the switching element 3 is terminated.

Next, the connection of the closed loop including the switching element 4 is confirmed. In step a7, the signal control circuit 2 sets the signal S2 to H, and in step a8, the contact 4
a, common line CL, limiting resistor 22, light emitting diode 2
1a or 21b, common terminal Tc, power supply P1, load L
2. Whether the closed loop of the terminal T2 and the contact 4a is formed is determined by the level of the signal p1. When the signal p1 is H, this closed loop is determined to have an abnormality. On the other hand, when the signal q1 is L, the process proceeds to step a9, where the signal S2 is set to L. It is determined on the basis of the level of the signal p1 whether the operation has been performed.

Hereinafter, although not shown, connection confirmation is similarly performed for a closed loop including other switching elements (step a (4n-1) to step a (4n +
2)) If all closed loops are normal, step a
At (4n + 3), the signal q1 is set to H, and the contact 31a
Is made conductive.

In this way, it is possible to easily confirm the wiring connection state of the closed loop of the load circuit including each switching element.

By storing and executing the connection confirmation program for executing the above-described flowchart in the signal control circuit 2, it is possible to automatically confirm the closed loop connection without manual operation, Even if the number of closed loops in the circuit increases and the circuit becomes complicated, it is possible to accurately and quickly check the connection of the closed loop.

In the above embodiments, the case where each switching element is realized by a relay has been described. However, each switching element is a solid state relay, a thyristor, a transistor, a triac, etc., and their inputs and outputs are insulated. However, the present invention can be applied to such a case.

In the above embodiment, the case where the current detecting means is realized by the photocoupler has been described. However, if the current detecting means in the closed loop can output the current detection to the signal control circuit 2, it is connected in series with the resistor. A voltmeter connected in parallel with an ammeter and a resistor may be used. Specifically, a semiconductor light receiving element such as a photodiode or CdS receives light emitted from a light source such as a lamp or a light emitting diode, and a signal control circuit. 2, a means for detecting sound from a sound source such as a buzzer or a piezoelectric buzzer with a microphone or the like and outputting the sound to the signal control circuit 2 may be used.

Further, by automatically executing the connection confirmation program before executing the normal load control program, the closed loop of the load circuit can be quickly confirmed. It is possible to efficiently detect a malfunction of the element, shorten the time required for the checking operation, save labor, and eliminate human error in the checking operation. Further, it is possible to prevent an accident or a failure due to a malfunction of the switching element from occurring.

[0026]

As described above, according to the present invention, the formation of the closed loop of each load circuit can be easily confirmed by the current detecting means interposed in the common line. It is possible to efficiently and accurately check the failure of the switching element that controls the load operation.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a schematic configuration of a load control device according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation for confirming a wiring connection state of a load circuit.

FIG. 3 is a timing chart of input / output signals of a signal control circuit.

FIG. 4 is a circuit diagram showing a schematic configuration of a conventional load control device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Load control device 2 Signal control circuit 3, 4, 31 Switching element 3a, 4a, 31a Contact 3b, 4b, 31b Coil 5 Power supply circuit 21 Photocoupler 21a, 21b Light emitting diode 21b Phototransistor CL Common line D1, D2 For surge absorption Diode Dp Light emitting diode L1, L2 Load P1 Power supply R1a, R1b, R2a, R2b, Rqa, Rqb Input resistance Rp Resistance T1, T2 terminal Tc Common terminal TR1, TR2, TRq Transistor V Power supply line

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01R 31/02

Claims (1)

(57) [Claims] 1. A load control device, wherein a plurality of load circuits in which a load and a first switching element are connected in series are connected to a power supply through a common line, wherein the load circuit includes a second switching element inserted in the common line. A current detecting means connected in parallel with the second switching element, and a limiting resistance element connected in parallel with the second switching element and in series with the current detecting means for limiting the current so that the load does not operate. A load control device comprising: disconnecting a second switching element and sequentially conducting a first switching element to check a wiring connection state of a load circuit.