JPH04107810U - Self-diagnosis circuit for electromagnetic drive circuit with overcurrent prevention function - Google Patents

Abstract

(57) [Summary] [Configuration] Current detectors 6a, 6b, and 6c are provided to detect overcurrent flowing through each solenoid 1a, 1b, and 1c, and the detection results are transmitted through comparators 7a, 7b, and 7c, respectively. Based on the overcurrent signal inputted to the interrupt port of the controller 3, the respective control elements 2a, 2b, and 2c are turned off, or the switch 4 is switched to the self-diagnosis detection circuit. switch to the side or
Self-diagnosis circuit for electromagnetic drive circuit with overcurrent prevention function that performs both operations. [Effect] While inheriting the diagnostic function and merits of the conventional technology, it is possible to detect and prevent overcurrent. Also,
Since the detection results are digitized via a comparator and input to the interrupt port of the controller, the output side of the comparator can be input all at once to the interrupt port. It is also possible to incorporate this into a CPU without adding an IC dedicated to interrupts or the like.

Description

[Detailed explanation of the idea]

0001 [Industrial application field] This invention is used for remote control of solenoid valves in hydraulic equipment such as hydraulic cranes. Regarding improvement technology for self-diagnosis circuits of electromagnetic drive circuits, in particular, This invention relates to a self-diagnosis circuit with an additional current prevention function.

0002 [Conventional technology] As a self-diagnosis technology for this kind of electromagnetic drive circuit, each solenoid in the electromagnetic drive circuit Turn off control elements such as transistors connected to the solenoid and controlling the drive of the solenoid. state, each solenoid is inactive, and the anti-power supply of the solenoid at this time is The potential on the side is detected by a self-diagnosis detection circuit, and depending on the voltage level, the electromagnetic Devices that self-diagnose failures such as disconnection failures and short-circuit failures in drive circuits are known. In addition, as an improved technology for this self-diagnosis technology, we have also developed a self-diagnosis method for each solenoid. Instead of providing a disconnection detection circuit, one self-diagnosis detection circuit is installed in each solenoid. A device has been proposed that can be used for the diagnosis of (see official bulletin).

0003 [The problem that the idea attempts to solve] However, the self-diagnosis technology in the prior art is limited to solenoid drive control. Before diagnosis, turn off all the control elements and make the electromagnetic drive circuit inactive. Since it is assumed that the electromagnetic drive circuit is disconnected, overcurrent during operation of the electromagnetic drive circuit is detected. It was not possible to prevent this. In view of this, the present invention uses a single self-diagnosis detection circuit to diagnose the failure of each solenoid. We have further improved the conventional self-diagnosis technology, which is also used for diagnostics, and added a simple configuration. Therefore, the diagnostic functions and benefits of this conventional self-diagnosis technology can be directly utilized. It is possible to detect and prevent overcurrent in the operating state of the electromagnetic drive circuit. The focus is on providing a self-diagnosis circuit for electromagnetic drive circuits with an overcurrent prevention function. There's a point.

0004 [Means to solve the problem] In order to solve the above-mentioned problems, the present invention aims to provide a power supply for electromagnetic drive or a power supply for failure diagnosis. A self-diagnosis detection circuit that is connected to a power supply and inputs the detection results to the controller. A switching device selectively connects to an electromagnetic drive circuit to which multiple solenoids are connected. The controller is configured to switch according to the selection mode of the controller, and each of the solenoids is driven by a control element connected to the controller and controlled by the controller. In the electromagnetic drive circuit controlled by the In addition to installing a current detector to detect overcurrent flowing through the input to the interrupt port of the controller via a comparator, and either Based on the overcurrent signal from the comparator, each control element is inverted to the OFF state or Switch the switch to the self-diagnosis detection circuit side, or operate both. We adopted technical means to configure it as follows.

[0005] [Effect] By adopting the technical means, the present invention improves the diagnostic function of the conventional self-diagnosis technology. In addition to inheriting the advantages of The addition of current detection and prevention functions prevents overcurrent from occurring during operation of the electromagnetic drive circuit. If the overcurrent is detected, the control element is turned off and the current is turned off. Place the magnetic drive circuit in a non-operating state or switch the switch to the self-diagnosis detection circuit side. Since the drive power supply to all solenoids is then stopped, solenoid noise due to overcurrent This prevents malfunctions such as card burnout, and also enables self-diagnosis, making it extremely easy to use. A self-diagnosis circuit for an electromagnetic drive circuit that is extremely safe and easy to use can be provided.

[0006] 〔Example〕 Next, embodiments of the present invention will be described based on the drawings. In the figure, 1a, 1b, 1c is a solenoid that generates electromagnetic driving force, and each has a control element consisting of a transistor, etc. It is driven and controlled by a controller 3 via children 2a, 2b, and 2c. The skit The roller 3 is constituted by a microcomputer, etc., and receives a mode selection input signal Sd. The drive control mode or diagnostic mode is selected based on the each operation is executed. In the drive control mode, switch 4 is connected to the electromagnetic drive power source. Each solenoid 1a is switched to the Vs side based on an operation command input signal (not shown). , 1b, 1c are individually driven and controlled. On the other hand, in the diagnostic mode, the switching Switch the switch 4 to the fault diagnosis power supply Vm side, and connect the switch between the resistor Rm and the switch 4. A detection signal for diagnosis is input to the controller 3 via the voltage level detector 5. In addition, by these fault diagnosis power source Vm, resistor Rm, and voltage level detector 5, A detection circuit for fault diagnosis is configured, and the power supply for fault diagnosis Vm is set low. There is. In the figure, 6a, 6b, and 6c are current detectors, each with a current detection resistor. Ra, Rb, and Rc, and the detection results are sent to comparators 7a and 7b, respectively. , 7c. In each of these comparators 7a, 7b, 7c, the input The current value that is the detection result is compared with each setting value a, b, c, and the current value is When the value exceeds the fixed values a, b, c, the output is reversed and the controller 3 Input the occurrence of overcurrent to the input port. In addition, in the figure, Da, Db, and Dc are the Rd, Re, and Rf represent current-limiting resistors, respectively.

[0007] Next, the method of operation of this embodiment will be explained. In drive control during normal operation, the mode selection input signal Sd is Therefore, when the drive control mode is selected, the switch 4 switches to the electromagnetic drive power supply V. The controller is switched to the s side based on an operation command input signal (not shown). Each solenoid 1a, 1b, 1c is individually driven and controlled by the controller 3. Also, In fault diagnosis, the diagnosis mode is selected by the mode selection input signal Sd. When this happens, each of the control elements 2a, 2b, 2c is switched to the OFF state. At the same time, the switch 4 is switched to the failure diagnosis power supply Vm side, and the resistors Rm and The detection results for diagnosis are sent to the computer via the voltage level detector 5 connected between the switching devices 4. The voltage level is input to the controller 3, and the voltage level that is the detection result is input to the controller 3. Fault diagnosis is performed depending on the In addition, in the above operation, the above-mentioned conventional self-diagnosis There is no difference from cutting technology.

[0008] Next, the feature of this invention is that if an overcurrent occurs for some reason during operation, This section explains the overcurrent prevention operation that detects this and prevents the continuation of the abnormal condition. Ru. During normal drive control operation, one of the solenoids may fail due to some reason. When an overcurrent occurs in 1a, 1b, 1c, the solenoid connected to the solenoid where the overcurrent occurred is connected. detected by one of the current detectors 6a, 6b, 6c, and the corresponding comparator 7a, 7b, and 7c, and the output is inverted to interrupt the controller 3. An overcurrent occurrence is input to the port. Based on this, the controller 3 , the mode is switched to the diagnostic mode, and the control elements 1a, 1b, 1c are When a control signal is issued and all control elements 1a, 1b, 1c are turned off, At the same time, a switching command signal is also issued to the switching device 4, and a switching command signal is sent to the fault diagnosis detection circuit side. can be switched to This causes the control elements 1a, 1b, 1c to turn off. The reversal prevents the overcurrent from continuing, and the switching of the switch 4 prevents the overcurrent from continuing. The continuation of the above-mentioned overcurrent is doubly prevented by cutting off the electromagnetic drive power supply. Become. Thereafter, by switching the switch 4 to the fault diagnosis detection circuit side, the Needless to say, the self-diagnosis operation described above is started. In addition, in the above explanation, we will explain the case where three solenoids are used. However, it goes without saying that there is no need to be limited to that number. In addition, in the above explanation, the overcurrent detection signal is input to the controller 3. Then, the selection mode is switched to the diagnosis mode in the controller 3, and each of the above An off command signal is issued to the control elements 1a, 1b, 1c, and all the control elements 1a, 1c are turned off. 1b and 1c to the OFF state, and also sends a switching command signal to the switching device 4. Explains the case where the configuration is configured to emit a signal and switch to the fault diagnosis detection circuit side. However, instead of this, an off command signal is sent to each of the control elements 1a, 1b, 1c. or a configuration in which a switching signal is issued to the switching device 4 is adopted. However, the start of self-diagnostic operation is performed by inputting a separate mode selection input signal. It is also possible to configure

[0009] [Effect of idea] The present invention can obtain the following effects based on the above configuration. (1) Conventional technology that also serves as a detection circuit for self-diagnosis and overcurrent detection and detection of each solenoid. In conjunction with the prevention technology, it inherits the diagnostic functions and benefits of the conventional technology. Furthermore, it is possible to detect and prevent overcurrent during operation, which was not possible with conventional technology. Therefore, the safety of the electromagnetic drive device as a whole can be greatly improved. (2) Moreover, the configuration is simple, just adding a current detector and a comparator. , its cost is also low. (3) The detection results of the current detector for overcurrent detection are digitized via a comparator and Since the input is configured to be input to the interrupt port of the controller, the output side of the comparator can be input all at once to the interrupt port, which reduces the number of interrupt ports. It can be incorporated into a general CPU without adding an interrupt-specific IC, etc. is possible. (4) Because the configuration is simple, failures are less likely to occur.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram in an embodiment of the present invention.

[Explanation of symbols]

1a, 1b, 1c... Solenoid 2a, 2b, 2c...control element 3. Controller ４‥‥Switcher 5. Voltage level detector 6a, 6b, 6c...Current detector 7a, 7b, 7c... Comparator Vs‥‥Electromagnetic drive power supply Vm‥‥Power supply for failure diagnosis Sd... Input signal for mode selection

Claims (2)

[Scope of utility model registration request] [Claim 1] A self-diagnosis detection circuit that is connected to an electromagnetic drive power source or a failure diagnosis power source and inputs the detection result to a controller is selectively connected to an electromagnetic drive circuit to which a plurality of solenoids are connected. The switching device is configured to be switched depending on the selected mode of the controller, and the electromagnetic drive circuit is connected to each of the solenoids and whose drive is controlled by a control element that is controlled by the controller. , a current detector is provided to detect the overcurrent flowing through each of the solenoids, and the detection results are input to the interrupt port of the controller via the respective comparators, and the overcurrent signal from one of the comparators is used. 1. A self-diagnosis circuit for an electromagnetic drive circuit with an overcurrent prevention function, characterized in that the control element is inverted to an OFF state when the control element is turned off. [Claim 2] A self-diagnosis detection circuit that is connected to an electromagnetic drive power supply or a failure diagnosis power supply and inputs the detection results to a controller is selectively connected to an electromagnetic drive circuit to which a plurality of solenoids are connected. The switching device is configured to be switched depending on the selected mode of the controller, and the electromagnetic drive circuit is connected to each of the solenoids and whose drive is controlled by a control element that is controlled by the controller. , a current detector is provided to detect the overcurrent flowing through each of the solenoids, and the detection results are input to the interrupt port of the controller via the respective comparators, and the overcurrent signal from one of the comparators is used. A self-diagnosis circuit for an electromagnetic drive circuit with an overcurrent prevention function, characterized in that the switch is configured to switch to the self-diagnosis detection circuit side.