JPH01265313A - Energization control system and circuit thereof for equipment - Google Patents

Abstract

PURPOSE:To prevent the breakage of an equipment due to the wrong energization by using an AND of control signals of at least two systems to turn on a switch part. CONSTITUTION:A relay 5 is energized only when both transistors TR 6 and 7 are turned on and the set signal of the cooling operation, for example, is transmitted through a terminal P of a control part 8. At the same time, the energization signal of a compressor1 is transmitted through a terminal Q based on a thermo-cycle. Therefore the relay 5 is energized when the set signal is transmitted from the terminal P and the energization signal of the compressor 1 is transmitted from the terminal Q respectively. In other sides, the constantly opened contact pieces 2 and 3 are closed and the compressor 1 is energized. As a result, the wrong energization of the compressor 1 is avoided even through one of both systems of the TR 6 and 7 is broken or short-circuited and kept turn-on.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to preventing erroneous energization of equipment due to malfunction of a switch section.

(b) Conventional technology In general, as a current control circuit for conventional equipment, the
There was something like the one described in Publication No. 12334. The device described in this publication controls the energization of a motor by opening and closing contacts of a relay, and this relay is controlled via an auxiliary relay. The auxiliary relay was controlled to be energized or de-energized by a transistor ON10FF. Therefore, by controlling ON/OFF of the transistor, it was possible to control the energization of the motor.

(C) Problems to be Solved by the Invention In such conventional energization control circuits, there was only one circuit that controlled the energization to the equipment by turning ON/OFF the transistor, so if this transistor malfunctioned, the equipment would also be affected. For example, if this transistor is damaged due to static electricity, a short circuit between terminals due to vibration, or a short circuit between terminals due to the intrusion of insects or foreign objects, an ON signal will not be given to the transistor. There was a problem in which the device was turned on even though it was not turned on and the device was erroneously energized.

This was a particularly serious problem when equipment such as burners, combustors, compressors, and pumps were used.

In view of this problem, the present invention provides an energization control system and an energization control circuit in which the equipment is not erroneously energized even if one system malfunctions by controlling the energization of the equipment using two or more systems.

(d) Means for Solving the Problems The present invention provides an energization control method for equipment in which the energization of the equipment is controlled by ON/OFF of a switch part. It is something to do.

Further, the excitation winding of the relay, the first switch section, and the second switch section are connected in series between the power supply terminals, and control signals of different systems are applied to the first switch section and the second switch section, respectively. .

In addition, it is equipped with a circuit that detects the state that changes due to energization of the device with a detector, and controls the ON/OFF of the switch section with a signal obtained based on the detected value of this detector and a control signal. This device is equipped with a circuit that turns off the switch section when the value exceeds a predetermined value.

It also includes a detection unit that detects the energization of the device, and turns the switch unit ON/OFF using the ON10FF signal from the control unit, and also turns the switch unit on and off when the detection unit detects the energization of the device when the OFF signal is output from the control unit. This is to cut off the electricity to the

(*) Function: In the energization control system and energization control circuit for devices configured in this way, the switch section that directly controls the energization of the device is turned on.
Since the 10 FF is performed using two systems of signals, even if one system malfunctions, the equipment can be prevented from being erroneously connected by the signals of the other system.

In addition, by using one of the two systems as a signal based on the energization state of the device or a state that changes with the energization of the device, feedback from the device can be obtained and erroneous energization of the device can be reliably prevented.

(f) Examples Examples of the present invention will now be described based on the drawings. FIG. 1 is a schematic diagram of a device in which a single-phase compressor 1 is used, and the compressor 1 is connected to a power source 4 via normally open contacts 2 and 3. The normally open contacts 2 and 3 close the contact pieces by energizing the relay 5 to control the energization of the compressor 1. 6 and 7 are a PNP type switching transistor and an NPN type switching transistor, respectively, and the former is connected to relays 5 and D.
C24 (V) power supply, the latter is connected to relay 5
and ground potential.

Therefore, relay 5 is energized only when both transistors 6, 7 are in the ON state. Note that the base terminal of the transistor 6 is connected to a terminal P of the control section 8 via an inverter circuit 9. The base terminal of the transistor 7 is directly connected to the terminal Q of the control section 8. For example, a setting signal for cooling operation is output from the terminal P of the control unit 8, and an energization signal for the compressor 1 based on the thermocycle is output from the terminal Q. Therefore, the relay 5 is turned on when the setting signal is output from the terminal P and the energization signal for the compressor 1 is output from the terminal Q. That is, the normally open contacts 2 and 3 are closed, and the compressor 1 is de-energized. Therefore, even if one of the transistors 6, 7 is damaged or short-circuited and the transistor is turned on, the compressor 1 will not be erroneously energized.

Figure 2 shows a compressor 10 in the equipment similar to that shown in Figure 1.
It is a schematic diagram when using. Reference numeral 11 denotes a detector for detecting the state (circulation amount of refrigerant gas) that changes depending on the operation of the compressor 10, and includes a gas amount detection element 12 and resistors 13 to 1.
8 are connected in a bridge shape. Comparators 19 and 20 set the output to L level (ground level) when the refrigerant gas exceeds a higher predetermined value or a lower predetermined value. Note that these comparators 19.
A constant differential is set for the switching operation of the HeL level of the 20 outputs. 21 is a control unit;
It has an analog/digital input terminal A/D for inputting the detected value of the detector 11, and a terminal Q for outputting an ON/OFF signal for the compressor 10 based on the thermocycle and the detected value. In other words, it adjusts the cycle of the thermocycle according to the value of the gas amount detected by the detector 11, and outputs a signal (L level voltage) that turns off the operation of the compressor 10 regardless of the thermocycle in a gas shortage state. do. 22 is an inverter element which inverts the output signal from the terminal Q and then outputs it to the switching transistor 23.

24 is a switching transistor that controls the energization of the relay 25, and its base terminal is connected to the output terminals of the comparators 19 and 20 and the collector terminal of the transistor 23. In this transistor 24, the outputs of the comparators 19 and 20 are both H-level voltages, and the H-level voltage is output from the terminal Q of the control section 21, so that the transistor 24
It becomes ON only when is in OFF state. When the transistor 24 turns on, the relay 2
5 is energized, the normally open contacts 26 and 27 are closed, and the compressor 10 is energized.

In the control circuit configured in this way, the control unit 21 inputs the gas amount detected by the detector 11 from the terminal A/D, and
When the amount of gas exceeds or falls below a predetermined amount, the output of terminal Q is set to L level and energization to relay 25 is cut off. That is, the normally open contact pieces 26, 27 are opened and the compressor 10 is stopped. At this time, even if the transistor 23 becomes OFF due to some abnormality or an H level output is output from the terminal Q due to a malfunction of the control unit 21, one of the outputs of the comparators 19 and 20 becomes an L level output. Therefore, the transistor 24 remains in the OFF state, and the relay 25
is not energized, ie, the compressor 10 remains stopped.

FIG. 3 is a schematic diagram of a case where a compressor 28 is used in the equipment similar to that shown in FIGS. 1 and 2.

In the figure, 29 is a control unit, and the ONi number (H
level voltage) or OFF signal (L level voltage). Reference numeral 30 denotes a switching transistor, which turns L; -CON10FF in response to the output of the terminal Q of the control section 29. 3
1 t, -32 (7) This is a switching transistor that controls energization.

Therefore, the relay 3z is energized when the output of the control section 29 is at H level heavy pressure, and the normally open contacts 33 and 34 are closed to close the compressor 2.
8 is energized. 35 is a photocoupler, and when the normally open contact pieces 33 and 34 are closed, the light emitting element lights up, the light receiving element side is turned on, and an H level voltage can be output to the resistor 36. Therefore, the AND gate 37 is supplied with the H level voltage from the resistor 36 and the L level voltage inverted by the inverter circuit 38, so that the output of the AND gate 37 becomes the L level voltage, and the switching transistor 39 It remains in the OFF state. When the output of the AND gate 37 becomes an H level voltage, the light receiving element of the photocoupler 35 is in the ON state and the output of the terminal Q of the control section 29 is an L level voltage. That is, the output of the terminal Q of the control unit 29 is at the L level voltage (when the compressor is OFF).
This is when the compressor 2B is in the energized state even though the compressor 2B is being outputted. This state occurs when the switching transistor 30 is short-circuited due to damage or for some reason, or when it is turned on. and gate 3
7 becomes an H level voltage, the switching transistor 39 is turned on, and the switching transistor 31 is turned off, cutting off the power to the compressor 28. Note that 40 is a capacitor for preventing the output of the AND gate 37 from chattering.

In the circuit configured in this way, when the compressor 2B is energized even though the OFF signal for the compressor 28 is output from the terminal Q of the control section 29, the output of the AND gate 37 becomes an H level voltage. Then, the transistor 39 turns on, cutting off the power supply to the compressor 28 and preventing the compressor 28 from being erroneously energized.

(G) Effects of the Invention The present invention provides an energization control method for equipment in which the energization of the equipment is controlled by ON/OFF of a switch unit, in which the ON operation of the switch unit is performed by the logical product of at least two systems of control signals. Even if an erroneous signal occurs in a system, it is possible to prevent equipment from being erroneously energized by control signals from other systems, and damage to equipment due to erroneous energization can be suppressed. Furthermore, if the signal from another system is turned into a signal fed back when the device is energized, incorrect energization of the device can be reliably detected, and power to the device can be cut off to prevent damage to the device.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a schematic diagram of an energization control circuit showing an embodiment of the present invention;
Fig. 2 is a schematic diagram of an energization control circuit showing another embodiment;
The figure is a schematic diagram of an energization control circuit showing still another embodiment. 1... Compressor, 2, 3... Normally open contact piece, 5...
Relay, 6, 7...Transistor, 8...Control unit.

Claims (4)

[Claims] (1) In a device energization control method in which the device's energization is controlled by ON/OFF of the switch section, the switch section's O
1. A device energization control system characterized in that N operations are performed by logical product of at least two systems of control signals. (2) In an energization control circuit that controls energization of equipment by opening and closing contacts of a relay, the excitation winding of the relay, a first switch section, and a second switch section are connected in series between power terminals, and the first switch 1. An energization control circuit for a device, characterized in that control signals of different systems are applied to the section and the second switch section, respectively. (3) In the energization control circuit that controls the energization of the device by turning ON/OFF the switch section, a detector detects the state that changes due to the energization of the device, and the energization is obtained based on the detection value of this detector and the control signal. Switch ON/O by signal
1. An energization control circuit for a device, comprising a circuit for controlling an FF and a circuit for turning a switch part into an OFF state when a detection value of a detector exceeds a predetermined value. (4) In the energization control method in which the energization of the device is controlled by ON/OFF of the switch section, the energization control method includes a detection section that detects the energization of the device, turns the switch section ON/OFF with an ON/OFF signal from the control section, and A method for controlling energization of a device, characterized in that when a detection section detects energization of the device when an OFF signal is output from the control section, a protective operation is performed to cut off the power supply to the device.