JPH11112310A - Contact input signal processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To greatly reduce unnecessary power consumption by making it possible to turn off a switching circuit at the time needed to inform a CPU of a contact state. SOLUTION: A switching circuit S" in the contact input signal processor is set in a normally-off state and a control circuit 1 turns on the switching circuit SW for a certain time when a contact state read command is sent from the CPU 2 to the control circuit 1. At this time, a DC voltage DC110 V is applied to contacts S1, S2 and Sn and the output signal of a photocoupler turns on for a contact in an on-state, so that the CPU 2 recognizes this state. Only when the switching circuit SW turns on with the contact state read command from the CPU 2, power consumption is generated at each contact input circuit and the command from the CPU 2 is almost momentary as compared with other processes of the CPU 2, so the total power consumption greatly decreases.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact input signal processing device connected to a monitoring control device or a data collection device.

[0002]

2. Description of the Related Art In a substation or the like in which a circuit breaker or a transformer is installed, a device for constantly reading and monitoring various contacts of the on-site equipment is provided. To read the contact state, a contact input signal processing device including a contact input circuit is usually used. FIG. 7 shows a circuit diagram of a conventional contact input signal processing device. Field contact S1 to Sn
Are photocouplers PC1, PC2,. . . . PC
n is connected to DC110V. Some of the contacts are always off, as in S1, and others are always on, as in contact S2. Each photo coupler PC
Detects the state of these contacts and outputs the signal to the subsequent CPU as a signal indicating the contact state.

[0003]

However, in the above-described device, since a voltage is constantly applied to each contact, a power is not supplied to the contact input section which is always on such as the contact S2. Power consumption is always performed, and when the number of contacts is large, there is a disadvantage that power consumption becomes so large that it cannot be ignored. In particular, when the applied voltage is set as high as 110 V to blow off the oxide film generated on the contact surface, the power consumption becomes extremely large. On the other hand, the ON / OFF information of the contact is actually required only on the CPU side when the CPU reads the contact state, and the time required for the read cycle of the CPU is several μsec to several tens μsec. Because of that,
Usually, it is very short. That is, the conventional contact input signal processing device has a disadvantage that most of the consumed power is wasted. Further, the heat generated by the power consumption has a disadvantage that the number of contacts that can be processed by a card (substrate) on which the contact input signal processing device is mounted is greatly limited.

SUMMARY OF THE INVENTION [0004] An object of the present invention is to provide a contact input signal processing device capable of drastically reducing power wasted in a contact input circuit.

[0005]

The invention according to claim 1 is
It is characterized by comprising a switching circuit inserted in series with the contact input circuit, and a control circuit that turns on the switching circuit for a certain period of time when reading the contact state.

That is, in this device, the switching circuit is turned on for a certain period of time when reading the contact state, so that the contact input circuit does not consume power at other times. The certain time in this case is the shortest time required for reading the contact state, that is, the CPU.
Any time required to provide the ON / OFF information of the contact to the switch is sufficient. At other times, the switching circuit is turned off, so that unnecessary power consumption can be completely eliminated.

According to a third aspect of the present invention, the control circuit includes a contact state read command terminal for receiving a contact state read command from the outside when reading the contact state, and a contact state for outputting a contact state read end when the contact state reading is completed. A read end terminal, and the control circuit turns on the switching circuit when receiving a contact state read command from outside,
Thereafter, the contact state reading end signal is output.

With this configuration, by connecting the contact status reading end terminal of the n-th contact input signal processing device to the contact status reading command terminal of the (n + 1) th contact input signal processing device, each setting input signal is set. The processing devices can be connected in cascade, whereby contact information is read in each device one after another.

The invention according to a fourth aspect is characterized in that the control circuit includes counter means for outputting a contact state read command signal every time the clock count value reaches a predetermined value.

In this configuration, each contact input signal processing device independently reads the contact state. In this case, by appropriately adjusting the count-up value of the counter means included in each device, the CPU can appropriately operate. The contact state detected by each device can be read at an appropriate timing.

The invention according to claim 5 is characterized in that a latch circuit is provided for latching a contact signal of the contact input circuit when reading a contact state.

By providing a latch circuit, the contact state read this time can be held until the next contact state is read, so that the CPU can read out the contact signal latched at an arbitrary timing during that time, and the CPU processing The degree of freedom can be increased.

[0013]

FIG. 1 is a circuit diagram of a contact input signal processing device according to an embodiment of the present invention.

This contact input signal processing device differs from the conventional device shown in FIG. 7 in that a switching circuit SW inserted in series with the contact input circuit and a switching circuit S
The point is that a control circuit 1 for controlling ON / OFF of W is provided. The control circuit 1 is controlled by a CPU 2 connected to the subsequent stage of the device. The output of each photocoupler PC is input to the CPU 2 and the CP
It is digitized and signal processed in U2.

In FIG. 1, a switching circuit SW in a contact input signal processing device is always set to an off state. When a contact state read command is issued from the CPU 2 to the control circuit 1, the control circuit 1 turns on the switching circuit SW for a predetermined time. At this time, each of the contacts S1, S2,. . . . DC voltage DC for Sn
For contacts that are 110 V applied and are in the on state,
The output signal of the photocoupler is turned on, and the CPU 2 recognizes this state. Note that the voltage applied to each contact is
The reason why the voltage is set to a high voltage of V is that even when a thin oxide film is formed on each contact, the oxide film can be blown by applying such a voltage. Although FIG. 1 shows only the contact input signal processing device mounted on one substrate (card), a plurality of (100 to 200 in many cases) cards are actually used. Are mounted in a housing, and these output signals are input to the CPU 2. The CPU 2 has a built-in multiplexer that processes these many signals in order.

With the circuit configuration shown in FIG. 1, the contact input signal processing device consumes power in each contact input circuit only when the switching circuit SW is turned on in response to a contact state read command from the CPU 2. Is the CPU
2 is almost instantaneous compared to the other processes, so that the overall power consumption is drastically reduced. Note that the CPU 2 has a switching circuit S
Since the output signal of each photocoupler when W is turned on, that is, the contact signal indicating the contact state, is read, it is possible to mistakenly read the output signal of the photocoupler when the switching circuit SW is off as data of the contact state. Absent.
Also, the above command from the CPU 2 is issued periodically,
This period is much shorter than the ON / OFF fluctuation time of the contact that may fluctuate on / off (for example, several tens of times).
ms). Therefore, the state of such a floating contact is not overlooked.

The control circuit 1 has a switching circuit S
The fixed time for turning on W is the shortest time necessary for the CPU 2 to read the contact state, and is most desirable from the viewpoint of eliminating wasteful power consumption.
Can be set to a time that exceeds the shortest time required for the CPU to read the contact state, so that a margin can be provided.

FIG. 2 is a circuit diagram when a semiconductor switch composed of a photo MOS relay is employed as the switching circuit SW. The control circuit 1 is connected to a drive circuit of the photo MOS relay, and the photo MOS relay is turned on by a contact state read command signal from the control circuit, so that the CPU can read the contact signal.

FIG. 3 is a circuit diagram in which a latch circuit for latching a contact signal is provided in the contact input processing device.

In this circuit, each photocoupler PC1, P
C2,. . . . The contact signal from PCn is latched by the latch circuit 3. The latch signal is generated by the control circuit 1. Further, the control circuit 2 is provided with a contact state read command terminal A and a contact state read end terminal B,
The terminal B of the first card C1 and the terminal A of the second card C2 are connected. When there are three or more cards, the terminal B of the card C2 is connected to the terminal A of the card C3, and similarly, the cards are cascaded. 1
A contact state read command is input from the CPU 2 to the terminal A of the first card 1.

FIG. 4 is a timing chart of the circuit shown in FIG. First card C from CPU2
When there is a contact state read command at 1, the control circuit 1 outputs a start signal to the photo MOS relay PR. The photo MOS relay PR is turned on from this time, and is turned on only for a period T1 which is the same as the pulse width of the contact state read command signal. During this time, the contact state is read by the photo coupler PC. The signal is latched by the latch circuit 3 in response to a latch pulse, and a contact state reading end signal is output to the terminal B after the end of the time T1. Thereby, the latch circuit 3 has all the terminals S1, S1 connected to the card C1.
2,. . . . The state of Sn is captured. CPU2
Before issuing the next contact state read command signal, the signal latched in the latch circuit 3 at any time is fetched.

In the card C2, the contact state reading end signal sent from the card C1 to the terminal A is transmitted to the card C2.
The card C is read as the contact state read command signal of No. 2
2 operates in the same manner as the control circuit 1 of the card C1. The pulse width of the contact state reading end signal is T1, which is the same as the pulse width of the contact state reading command signal. Such an operation is sequentially repeated for each card. The reason why the cards are cascaded and the contact signals are sequentially latched from the upper card is that the CPU 2 can take in the signals sequentially latched from the upper card. When the performance of the CPU 2 is high, it is also possible to latch the contact signals simultaneously in each card and allow the CPU 2 to simultaneously capture the latched signals.

FIG. 5 is a circuit diagram showing another embodiment of the present invention. This contact signal input processing device does not cascade connect the cards, but latches the contact signals individually and independently. That is, the control circuit 1 includes the counter 10 that counts the system clocks SYS · CLK and counts up when the count reaches a certain number. When the counter 10 counts up, it outputs a latch signal to the latch circuit 3. The count-up value for each card is appropriately adjusted according to the capacity of the CPU 2,
The contact signals latched by a large number of cards need not be taken in by the CPU 2 at the same time. If the count-up value of the counter 10 is increased in order from the upper card C1, the contact signals sequentially latched from the upper card C1 are output to the CPU similarly to the cascade connection shown in FIG.
2 will be taken in. FIG. 6 shows a timing chart of the circuit shown in FIG. As shown in the figure, the latch timing in the latch circuit 3 of each card is slightly shifted. Thus, by providing a counter for each card and setting the latch timing, it is not necessary to connect each card. Even in this case, unnecessary power consumption can be eliminated.

As the switching circuit, any semiconductor switching element such as a normal transistor can be used in addition to the photo MOS relay.

[0025]

According to the present invention, since the switching circuit can be turned off at an unnecessary time for notifying the CPU of the contact state, wasteful power consumption can be drastically reduced.

When a plurality of contact input signal processing devices are used, the contact state reading end terminal of the n-th device is set to n + 1.
By connecting to the contact status read command terminal of the second device,
Each device can be connected in cascade, so that the CPU issues a contact status read command only to the first device, and then automatically reads the contact status sequentially in each device, and
Accordingly, the reading of the CPU can be performed in accordance with the sequential reading in each device, and thus there is an advantage that the load on the CPU is reduced.

Similarly, in the configuration in which the control circuit is provided with the counter means, by appropriately adjusting the count-up value of the counter means of each device, the CPU need not read the contact state detected by each device at once. , The burden is lighter.

Further, by providing a latch circuit for latching the contact signal of the contact input circuit when reading the contact state, the CPU can read the contact signal latched at an arbitrary timing. The degree of freedom can be increased.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of a contact input signal processing device according to an embodiment of the present invention.

FIG. 2 is a specific circuit diagram of the contact input signal processing device according to the embodiment of the present invention.

FIG. 3 is a specific circuit diagram of another embodiment of the present invention.

FIG. 4 is a timing chart of the circuit shown in FIG. 3;

FIG. 5 is a specific circuit diagram of another embodiment of the present invention.

FIG. 6 is a timing chart of the circuit shown in FIG. 5;

FIG. 7 is a circuit diagram of a conventional contact input signal processing device.

Claims (5)

[Claims] 1. A contact input signal processing device comprising: a switching circuit inserted in series into a contact input circuit; and a control circuit for turning on the switching circuit for a predetermined time when reading a contact state. 2. The contact input signal processing device according to claim 1, wherein the predetermined time is a shortest time required for reading the contact state. 3. The control circuit according to claim 1, further comprising: a contact state read command terminal for receiving an external contact state read command when reading the contact state; a contact state read end terminal for outputting a contact state read end when the contact state reading is completed; The control circuit turns on the switching circuit when receiving a contact state read command from outside, and thereafter outputs the contact state read end signal.
The contact input signal processing device as described in the above. 4. The contact input signal processing device according to claim 1, wherein said control circuit includes counter means for outputting a contact state read command signal every time the clock count value reaches a predetermined value. 5. A latch circuit for latching a contact signal of said contact input circuit when reading a contact state.
A contact input signal processing device according to any one of claims 1 to 4,