Safe torque turn-off control circuit and motor driver
Through the design of the signal isolation module and detection module, the circuit structure of the STO function is simplified, the problems of complex circuits and high cost in the prior art are solved, and the safety and reliability are improved.
Patent Information
- Application Number
- CN202311852169.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-29
- Publication Date
- 2025-07-01
AI Technical Summary
In the prior art, the addition of the diagnostic circuit of the STO function leads to complex circuits, taking up a large space, and increasing the circuit design cost.
Instead of complex diagnostic circuits, the signal isolation module and the detection module are used to replace the complex diagnostic circuit. The signal isolation module outputs a stop signal after receiving the STO signal. The detection module outputs a second stop signal when the signal feedback from the signal isolation module meets the preset conditions to control the execution module to stop torque output and performs fault detection on the signal isolation module.
The circuit structure is simplified, the space is occupied, the circuit design cost is reduced, and the equipment is improved.
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Figure CN120237984A_ABST
Abstract
Description
Technical Field
[0001] Embodiments of the present application relate to the field of motion control, and in particular, to a safe torque off control circuit and a motor driver. Background Art
[0002] In industrial automation production, drive devices such as inverters and servo drivers generally have a safe torque off (STO) function. This STO function can prevent the drive from generating torque in the motor when the motor stops, thus effectively preventing personal injury accidents caused by accidental motor startup and providing safety protection for the motion control system.
[0003] Due to the complex industrial environment, the STO function may malfunction. In related technologies, a diagnostic circuit is set up to diagnose the circuit that implements the STO function to avoid the failure of the STO function due to faults. However, in this solution, due to the addition of the diagnostic circuit, the overall circuit is relatively complex, and the electronic devices in the diagnostic circuit occupy more circuit board space, increasing the cost of circuit design. Summary of the Invention
[0004] Embodiments of the present application provide a safe torque off control circuit and a motor driver.
[0005] A safe torque off control circuit includes: a signal isolation module and a detection module;
[0006] The first input end of the signal isolation module is connected to the front-end module, and the first output end is connected to the execution module. When receiving the safe torque off (STO) signal sent by the front-end module, it outputs a first stop signal to the execution module;
[0007] The feedback input end of the detection module is connected to the first output end of the signal isolation module, the detection output end is connected to the second input end of the signal isolation module, and the turn-off output end is connected to the execution module. The detection module outputs a detection signal to the signal isolation module and outputs a second stop signal to the execution module when the signal fed back by the signal isolation module meets a preset condition.
[0008] Optionally, the signal isolation module includes an optocoupler and a current limiting unit;
[0009] The primary side of the optocoupler is connected to the first input end via the current limiting unit;
[0010] The second input end of the secondary side of the optocoupler is connected to the detection output end of the detection module, and the first output end of the secondary side of the optocoupler is connected to the power supply input end via a first resistor.
[0011] Optionally, the secondary side of the optocoupler further includes a second output terminal grounded.
[0012] Optionally, the safe torque off control circuit further includes a filtering module;
[0013] The filtering module is connected to the first output terminal of the secondary side of the optocoupler and is connected to the first input terminal of the execution module.
[0014] Optionally, the filtering module includes a second resistor and a first capacitor;
[0015] The first resistor, the second resistor, and the first capacitor are connected in series and then grounded. The first input terminal of the execution module is connected between the second resistor and the first capacitor. The feedback input terminal of the detection module is connected between the first resistor and the second resistor. The off output terminal of the detection module is connected to the second input terminal of the execution module.
[0016] Optionally, the execution module includes two buffer chips connected in series. The safe torque off control circuit includes two of the signal isolation modules. The two signal isolation modules are respectively connected to the same front-end module through the first input terminal and are respectively connected to the two buffer chips in one-to-one correspondence through the first output terminal;
[0017] The execution module stops outputting a driving signal to the rear-end drive circuit when any one of the buffer chips receives the first stop signal or the second stop signal.
[0018] Optionally, the detection module includes two feedback input terminals, and the two feedback input terminals are respectively connected to the first output terminals of the two signal isolation modules in one-to-one correspondence. The detection output terminal of the detection module is connected to the second input terminals of the two signal isolation modules.
[0019] Optionally, the detection module includes a microcontroller, and the microcontroller outputs the detection signal to the signal isolation unit according to a preset period.
[0020] Optionally, the safe torque off control circuit further includes a power supply unit, and the power supply input terminals of the signal isolation module and the detection module are respectively connected to the output terminal of the power supply unit.
[0021] A motor driver includes the safe torque off control circuit as described above and further includes a drive circuit. The safe torque off control circuit is connected to the drive circuit.
[0022] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:
[0023] After receiving the safe torque off signal, the signal isolation module outputs a first stop signal to the execution module. The detection module can output a detection signal to output a second stop signal when the signal fed back by the signal isolation module meets the preset conditions, so that the execution module stops outputting, avoiding the risk of the STO function failing due to the failure of the signal isolation module. The signal isolation module controls the execution module to stop torque output according to the STO signal of the front-end module, and the detection module detects the failure of the signal isolation module. While implementing the STO function, the circuit for implementing the STO function is detected, avoiding the hardware failure of the safe torque off circuit and improving the safety of the device. By designing the signal isolation module and the detection module to replace the complex diagnostic circuit, the overall structure of the safe torque off control circuit becomes simple, the occupied space is greatly reduced, and the cost of circuit design is reduced. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 Schematic diagram of an embodiment of the safe torque off control circuit of the present application;
[0025] Figure 2 Schematic diagram of another embodiment of the safe torque off control circuit of the present application;
[0026] Figure 3 Schematic diagram of another embodiment of the safe torque off control circuit of the present application;
[0027] Figure 4 Schematic diagram of an embodiment of the motor driver of the present application;
[0028] Figure 5 Schematic diagram of another embodiment of the motor driver of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0029] The embodiment of the present application provides a safe torque off control circuit and a motor driver.
[0030] In the automated production scenario, the diagnosis of the STO circuit is carried out by setting an additional diagnostic circuit for fault diagnosis. However, in the existing solutions, due to the addition of the diagnostic circuit, the overall circuit is relatively complex, occupying more circuit board space and having a higher cost. To solve the above problems, the control circuit and control system provided by the present application can realize fault diagnosis through the optocoupler module that replaces the diagnostic circuit. The overall circuit structure is simple, the occupied area is small, the cost is low, and the user experience is greatly improved.
[0031] The following describes the safe torque off control circuit of the present application. Please refer to Figure 1 , an embodiment of the safe torque off control circuit of the present application includes: a signal isolation module 101 and a detection module 102;
[0032] The first input terminal of the signal isolation module 101 is connected to the front-end module 103, and the first output terminal is connected to the execution module 104. When receiving the safe torque off (STO) signal sent by the front-end module 103, it outputs a first stop signal to the execution module 104. The front-end module 103 is used to generate the STO signal according to the state of the motor or the device driven by the motor, and the execution module 104 is used to output a driving voltage to the motor, so as to realize the driving control of the motor. When receiving the first stop signal, the execution module stops outputting the driving voltage to the motor.
[0033] The feedback input terminal of the detection module 102 is connected to the first output terminal of the signal isolation module 101, the detection output terminal is connected to the second input terminal of the signal isolation module 101, and the turn-off output terminal is connected to the execution module 104. The detection module 102 outputs a detection signal to the signal isolation module 101, and outputs a second stop signal to the execution module 104 when the signal fed back by the signal isolation module 101 meets the preset conditions. The second stop signal is used to instruct the execution module to stop outputting. That is, when receiving the second stop signal, the execution module stops outputting the driving voltage to the motor.
[0034] In the embodiment of the present application, after receiving the safe torque off (STO) signal, the signal isolation module 101 outputs a first stop signal to the execution module, and the detection module 102 can output a detection signal to output a second stop signal to control the execution module to stop torque output when the signal fed back by the signal isolation module 101 meets the preset conditions. The signal isolation module controls the execution module to stop torque output according to the STO signal of the front-end module, and the detection module detects the hardware of the signal isolation module. While realizing the STO function, the circuit for realizing the STO function can be detected, making the overall structure of the safe torque off control circuit simple, greatly reducing the occupied space, reducing the cost of circuit design, and improving the safety of the device.
[0035] Please refer to Figure 2 , another embodiment of the safe torque off control circuit of the present application includes: a front-end module, a signal isolation module, a detection module, an execution module, and a filtering module;
[0036] The first input terminal of the signal isolation module is connected to the front-end module, and the first output terminal is connected to the execution module. When receiving the safe torque off (STO) signal sent by the front-end module, it outputs a first stop signal to the execution module;
[0037] The feedback input terminal of the detection module is connected to the first output terminal of the signal isolation module, the detection output terminal is connected to the second input terminal of the signal isolation module, and the shutdown output terminal is connected to the execution module. The detection module outputs a detection signal to the signal isolation module and outputs a second stop signal to the execution module when the signal fed back by the signal isolation module meets the preset conditions. That is, the detection module outputs a detection signal to the signal isolation module through the detection output terminal and detects whether the feedback signal input from the signal isolation module at the feedback input terminal meets the expectation. If the feedback signal is not the expected level signal, it indicates that a fault has occurred in the signal isolation module, and then a second stop signal is output to the execution module through the shutdown output terminal to cause the execution module to stop outputting the drive voltage.
[0038] Among them, the signal isolation module includes an optocoupler OPTO1 and a current limiting unit (the third resistor R3 in this embodiment), the filtering module includes a second resistor R2 and a first capacitor C1, and the safe torque off control circuit further includes a first resistor R1;
[0039] The primary side of the optocoupler OPTO1 is connected to the first input terminal via the third resistor R3;
[0040] The second input terminal of the secondary side of the optocoupler OPTO1 is connected to the detection output terminal (OUT1 pin) of the detection module, and the first output terminal of the secondary side of the optocoupler is connected to the power supply input terminal (+5V terminal) via the first resistor R1;
[0041] The secondary side of the optocoupler further includes a grounded second output terminal (the fifth pin);
[0042] The filtering module is connected to the first output terminal (the fourth pin) of the secondary side of the optocoupler and is connected to the first input terminal (OE2 terminal) of the execution module.
[0043] The first resistor R1, the second resistor R2, and the first capacitor C1 are connected in series and then grounded. The first input terminal (OE2 terminal) of the execution module is connected between the second resistor R2 and the first capacitor C1. The feedback input terminal (IN1 terminal) of the detection module is connected between the first resistor R1 and the second resistor R2. The shutdown output terminal of the detection module is connected to the second input terminal (OE1 terminal) of the execution module.
[0044] The following is an introduction to the specific connection situation. The first pin of the primary side of the optocoupler OPTO1 is connected to the positive terminal STO1+ of the front-end module, the second pin of the primary side of the optocoupler OPTO1 is connected to the negative terminal STO1- of the front-end module. The secondary side of the optocoupler OPTO1 is provided with a third pin, a fourth pin, and a fifth pin. The third pin of the optocoupler OPTO1 is connected to the OUT1 terminal of the detection module, the fifth pin of the optocoupler OPTO1 is grounded, the first end of the first resistor R1 is connected to the +5V terminal, and the second end of the first resistor R1 is connected to the fourth pin of the optocoupler OPTO1.
[0045] The filtering module is connected between the fourth pin of the optocoupler OPTO1 and the OE2 terminal of the execution module, and is used to filter signals with frequencies higher than a preset threshold. Among them, the first end of the second resistor R2 is respectively connected to the second end of the first resistor R1, the fourth pin of the optocoupler OPTO1, and the IN1 terminal of the detection module. The second end of the second resistor R2 is respectively connected to one end of the first capacitor C1 and the OE2 terminal of the execution module. The other end of the first capacitor C1 is grounded;
[0046] The third resistor R3 is connected between the first pin of the optocoupler OPTO1 and the positive terminal STO1+ of the front-end module.
[0047] The working principle of the optocoupler OPTO1 is as follows:
[0048] Under normal circumstances, when the OUT1 pin is at a high level, the optocoupler output terminal is turned on. Regardless of whether the STO1+ pin and the STO1- pin are at high or low levels, the IN1 pin is at a low level; when the OUT1 pin is at a low level, the optocoupler is turned off, and the IN1 pin is fixed at a high level; when the OUT1 pin is in a high-impedance state (open), there are two cases. One is that if the STO1+ pin is at a high level, the optocoupler is turned on and the IN1 pin is at a low level. The other is that if the STO1+ pin is at a low level, the optocoupler is turned off and the IN1 pin is at a high level.
[0049] The working principle of the filtering module is as follows:
[0050] By setting the resistance value of the second resistor R2 and the capacitance value of the first capacitor C1, signals of a specific frequency are filtered out. In this embodiment, the filtering module is set to be able to filter signals with the same high frequency as the signal of the OUT1 pin. Signals exceeding a certain preset threshold can be filtered out. Or rather, high-level and high-frequency signals will be filtered out.
[0051] Regarding the diagnosis of the signal isolation module (i.e., diagnosing whether the optocoupler is damaged), the working principle of this embodiment is as follows:
[0052] Under normal circumstances, the detection module outputs a high-impedance signal, that is, the OUT1 pin is in a high-impedance state. At this time, the level of the IN1 pin is determined by the level of STO1+ (the specific analysis is as above). To diagnose the optocoupler OPTO1, the detection module periodically makes the OUT1 pin output a high-frequency signal with a low level. Then, when the optocoupler is normal, the IN1 pin corresponds to a high level. On the other hand, based on preset conditions (the detection signal is a low-level high frequency and the feedback signal is a high-level high frequency), the detection module analyzes according to the levels of the OUT1 terminal and the IN1 terminal of the output to detect whether the feedback signal conforms to the expected level signal. If the IN1 pin is not at a high level but at a low level when the OUT1 pin outputs a high-frequency signal with a low level, it is considered that the signal isolation module fails, and a high-level signal (i.e., the second stop signal) is output to the OE1 terminal of the execution module through the shutdown output terminal. After receiving the second stop signal, the execution module stops outputting the drive voltage to the motor.
[0053] In this embodiment, the design of the first signal isolation module and the detection module is used to replace the complex diagnostic circuit, making the overall structure of the safe torque off control circuit simple, greatly reducing the occupied space, reducing the cost of circuit design, and improving the safety of the equipment.
[0054] Please refer to Figure 3 , the safe torque off control circuit of the present application includes a front-end module, two signal isolation modules, a detection module, and an execution module;
[0055] The execution module includes two buffer chips connected in series. The safe torque off control circuit includes two signal isolation modules, and the two signal isolation modules are respectively connected to the same front-end module through the first input terminals, and are respectively connected to the two buffer chips in one-to-one correspondence through the first output terminals;
[0056] When any buffer chip in the execution module receives the first stop signal or the second stop signal, it stops outputting drive pulses to the drive circuit at the back end, thereby shutting down the motor. Through the above method, redundant control can be realized, and the safety of STO can be further improved.
[0057] The detection module includes two feedback input terminals, the two feedback input terminals are respectively connected to the first output terminals of the two signal isolation modules in one-to-one correspondence, and the detection output terminal of the detection module is connected to the second input terminals of the two signal isolation modules.
[0058] The detection module includes a microcontroller, and the microcontroller outputs detection signals to the signal isolation unit according to a preset period.
[0059] The safe torque off control circuit further includes a power supply unit, and the power supply input terminals of the signal isolation module and the detection module are respectively connected to the output terminal of the power supply unit.
[0060] Please refer to Figure 4 , an embodiment of the motor driver of the present application includes the safety torque off control circuit 401 as described above, and further includes: a drive circuit 402, and the drive circuit 402 is connected to an external motor 403;
[0061] There is at least one group of circuit module groups in the safety torque off control circuit 401. Each group includes a front-end module, a signal isolation module, and a buffer chip. All the circuit module groups share a detection module, and the signals output by the detection module to the buffer chips of each group are the same;
[0062] The buffer chip of each group is connected to the drive circuit 402;
[0063] The drive circuit 402 is connected to the motor 403 to control the operation or stop of the motor 403.
[0064] In this embodiment, each group of circuit module groups has its own corresponding signal isolation module and shares a detection module. Without a complex diagnostic circuit on the premise of being able to detect the corresponding front-end module respectively, the occupied area can be reduced, the design cost can be lowered, and the user experience can be greatly improved.
[0065] Please refer to Figure 5 , another embodiment of the motor driver of the present application includes a safety torque off control circuit and a drive circuit to control the motor. In this embodiment, the safety torque off control circuit includes two groups of circuit module groups. One group includes a first front-end module, a first signal isolation module, a first filtering module, and a first buffer chip of an execution module, and the other group includes a second front-end module, a second signal isolation module, a second filtering module, and a second buffer chip of an execution module. The two groups share a detection module, and the signals output by the detection module to each buffer chip are the same;
[0066] Among them, the first signal isolation module includes a first optocoupler OPTO1 and a third resistor R2, the first filtering module includes a second resistor R2 and a first capacitor C1, and the safety torque off circuit further includes a first resistor R1;
[0067] The first pin of the primary side of the first optocoupler OPTO1 is connected to the positive terminal STO1+ of the first front-end module, the second pin of the primary side of the first optocoupler OPTO1 is connected to the negative terminal STO1- of the first front-end module. The secondary side of the first optocoupler OPTO1 is provided with a third pin, a fourth pin, and a fifth pin. The third pin of the first optocoupler OPTO1 is connected to the OUT1 terminal of the detection module, the fifth pin of the first optocoupler OPTO1 is grounded, the first end of the first resistor R1 is connected to the +5V terminal, and the second end of the first resistor R1 is connected to the fourth pin of the first optocoupler OPTO1.
[0068] The first filtering module is connected between the fourth pin of the first optocoupler OPTO1 and the OE2 terminal of the first buffer chip, and is used to filter signals with a frequency higher than a preset threshold. The filtering module includes a second resistor R2 and a first capacitor C1. The first end of the second resistor R2 is respectively connected to the second end of the first resistor R1, the fourth pin of the first optocoupler OPTO1, and the IN1 terminal of the detection module. The second end of the second resistor R2 is respectively connected to one end of the first capacitor C1 and the OE2 terminal of the first buffer chip. The other end of the first capacitor C1 is grounded;
[0069] The third resistor R3 is connected between the first pin of the first optocoupler OPTO1 and the positive terminal STO1+ of the first front-end module.
[0070] One side of the second signal isolation module is connected to the second front-end module, and the other side is respectively connected to the detection module and the second filtering module. The second filtering module is connected to the second buffer chip;
[0071] The first execution module and the second buffer chip are connected in series to stop outputting the driving voltage to the motor when any buffer chip receives a control signal.
[0072] Among them, the second signal isolation module includes a second optocoupler OPTO2 and a sixth resistor R6. The second filtering module includes a fifth resistor R5 and a second capacitor C2. The safe torque off circuit further includes a fourth resistor R4;
[0073] The first pin of the primary side of the second optocoupler OPTO2 is connected to the positive terminal STO2+ of the second front-end module. The second pin of the primary side of the second optocoupler OPTO2 is connected to the negative terminal STO2- of the second front-end module. The secondary side of the second optocoupler OPTO2 is provided with a third pin, a fourth pin, and a fifth pin. The third pin of the second optocoupler OPTO2 is connected to the OUT1 terminal of the detection module. The fifth pin of the second optocoupler OPTO2 is grounded. The first end of the fourth resistor R4 is connected to the +5V terminal. The second end of the fourth resistor R4 is connected to the fourth pin of the second optocoupler OPTO2;
[0074] The first end of the fifth resistor R5 is respectively connected to the second end of the fourth resistor R4, the fourth pin of the second optocoupler OPTO2, and the IN2 terminal of the detection module. The second end of the fifth resistor R5 is respectively connected to one end of the second capacitor C2 and the OE1 terminal of the second buffer chip. The other end of the second capacitor C2 is grounded. The detection module is connected to the OE2 terminal of the second buffer module;
[0075] The sixth resistor R6 is connected between the first pin of the second optocoupler OPTO2 and the positive terminal STO2+ of the second front-end module.
[0076] The working principle of this embodiment is similar to the above related content. The difference is that the two groups of circuit module groups share a detection module, and the input signals input by the detection module to the first buffer chip and the second buffer chip are the same. This enables that as long as one of the multiple front-end modules fails, the detection module will fixedly give a high level to the execution module to shut down the motor.
[0077] In this embodiment, each group of circuit module groups has its own corresponding signal isolation module and shares a detection module, without a complex diagnostic circuit. This can reduce the occupied area and design cost on the premise of realizing the diagnostic function, and can also realize the isolation function, greatly improving the user experience.
[0078] The above has introduced the control circuit and control system provided by this application in detail. For those of ordinary skill in the art, according to the idea of the embodiments of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.
Claims
1. A safety torque off control circuit, characterized in that, Comprising: A signal isolation module and a detection module; The first input end of the signal isolation module is connected to the front-end module, the first output end is connected to the execution module, and when receiving the safe torque off (STO) signal sent by the front-end module, it outputs a first stop signal to the execution module; The feedback input end of the detection module is connected to the first output end of the signal isolation module, the detection output end is connected to the second input end of the signal isolation module, and the turn-off output end is connected to the execution module. The detection module outputs a detection signal to the signal isolation module and outputs a second stop signal to the execution module when the signal fed back by the signal isolation module meets the preset conditions.
2. The safety torque-off control circuit according to claim 1, wherein The signal isolation module includes an optocoupler and a current limiting unit; The primary side of the optocoupler is connected to the first input end via the current limiting unit; The second input end of the secondary side of the optocoupler is connected to the detection output end of the detection module, and the first output end of the secondary side of the optocoupler is connected to the power supply input end via a first resistor.
3. The safety torque-off control circuit according to claim 2, wherein The secondary side of the optocoupler further includes a grounded second output end.
4. The safety torque off control circuit according to claim 2, characterized in that The safe torque off control circuit further includes a filtering module; The filtering module is connected to the first output end of the secondary side of the optocoupler and is connected to the first input end of the execution module.
5. The safety torque off control circuit according to claim 4, wherein, The filtering module includes a second resistor and a first capacitor; The first resistor, the second resistor, and the first capacitor are connected in series and then grounded. The first input end of the execution module is connected between the second resistor and the first capacitor. The feedback input end of the detection module is connected between the first resistor and the second resistor. The turn-off output end of the detection module is connected to the second input end of the execution module.
6. The safety torque off control circuit according to claim 2, wherein The execution module includes two buffer chips connected in series. The safe torque off control circuit includes two such signal isolation modules, and the two signal isolation modules are respectively connected to the same front-end module through the first input end and are respectively connected to the two buffer chips in one-to-one correspondence through the first output end; The execution module stops outputting a drive signal to the rear-end drive circuit when any one of the buffer chips receives the first stop signal or the second stop signal.
7. The safety torque off control circuit according to claim 6, wherein The detection module includes two feedback input ends, and the two feedback input ends are respectively connected to the first output ends of the two signal isolation modules in one-to-one correspondence, and the detection output end of the detection module is connected to the second input ends of the two signal isolation modules.
8. The safety torque off control circuit according to any one of claims 1-7, characterized in that, The detection module includes a microcontroller, and the microcontroller outputs the detection signal to the signal isolation module according to a preset period.
9. The safety torque off control circuit according to any one of claims 1-7, characterized in that, The safe torque off control circuit further includes a power supply unit, and the power supply input ends of the signal isolation module and the detection module are respectively connected to the output end of the power supply unit.
10. A motor driver, characterized in that, Comprising the safe torque off control circuit according to any one of claims 1-9, further including a drive circuit, and the safe torque off control circuit is connected to the drive circuit.