Rotating speed detection and closed-loop control system based on photoelectric sensing and PLC

Abstract

The invention relates to the technical field of industrial automation control, and particularly discloses a rotating speed detection and closed-loop control system based on photoelectric sensing and a PLC, and the system comprises at least one rotating body which is a rotating speed controlled object, and the surface of the rotating body is provided with a configurable number of reflection mark areas or speed measurement holes; the proximity photoelectric switches are in one-to-one correspondence with the rotating bodies, are aligned with the reflection mark areas or the speed measurement holes, and are used for detecting rotation information of the rotating bodies and generating original pulse signals; a high-speed counter input port of the PLC is electrically connected with signal output ends of the proximity photoelectric switches, and a pulse preprocessing module, a rotating speed calculation module, a deviation processing module, a control algorithm module and a signal adaptation module are arranged in the PLC. The PLC and the proximity photoelectric switch which are widely applied in the industrial field and high in popularity rate are adopted as core technical components, and expensive special servo controllers, encoders and other devices are not needed, so that the hardware purchase cost of the system is greatly reduced.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of public transport systems, in particular to a rotating speed detection and closed-loop control system based on photoelectric sensing and PLC. BACKGROUND

[0002] In the field of industrial production, rotating equipment (such as motors, rollers, fans, pumps, etc.) is the core execution component of many production processes, and the accurate detection and stable control of its rotating speed is directly related to the smoothness of the production process, the stability of product quality, and the safety of equipment operation. For example, in a hot air circulation system, fluctuations in the rotating speed of the fan can lead to uneven temperature distribution, affecting the product heat treatment effect; in a conveyor belt system, unstable motor speed can cause material delivery to be blocked or stacked; in a stirring device, speed deviation can change the degree of material mixing, thereby affecting the performance of the final product, so accurate control of the rotating speed of rotating equipment is a key requirement in industrial production.

[0003] In the prior art, there are various schemes for controlling the rotating speed of rotating equipment, but all have obvious limitations. On the one hand, some simple control systems use tachogenerators in combination with analog circuits to achieve control. Although this type of scheme has a relatively simple structure, it is affected by the characteristics of analog circuits, and has problems such as low detection accuracy, susceptibility to electromagnetic interference, and difficulty in parameter adjustment, making it difficult to meet the requirements of industrial scenarios that require a certain level of control accuracy. On the other hand, some advanced control schemes use a combination of dedicated servo controllers and encoders, which can achieve high-precision rotating speed control, but the cost of dedicated equipment is high, the overall system structure is complex, the technical level of installation and debugging personnel is high, and the maintenance cost is also relatively high, making it unsuitable for ordinary industrial occasions that are sensitive to cost and have moderate control requirements.

[0004] As a core device in the field of industrial control, PLC (Programmable Logic Controller) has high reliability, strong anti-interference ability, and flexible programming and expansion capabilities, and can adapt to complex industrial environments. Proximity photoelectric switches are a mature, low-cost, and non-contact detection element that can stably obtain the motion information of rotating equipment. Currently, although there are some applications that simply combine PLC and proximity photoelectric switches, such applications mostly only stop at the level of rotating speed display or simple overspeed alarm, and do not fully utilize the powerful data processing capabilities and logic control functions of PLC, nor do they build a complete closed-loop control system, making it impossible to achieve dynamic adjustment and precise control of the rotating speed of rotating equipment. Therefore, how to deeply integrate PLC and proximity photoelectric switches and design a rotating speed closed-loop control system that is simple in structure, low in cost, and excellent in control performance to meet the actual needs of ordinary industrial occasions has become a technical problem that needs to be solved in this field. SUMMARY

[0005] In view of the deficiencies of the prior art, the application provides a rotating speed detection and closed-loop control system based on photoelectric sensing and PLC, which solves the problems in the background art.

[0006] To achieve the above object, the application is implemented by the following technical scheme: a rotating speed detection and closed-loop control system based on photoelectric sensing and PLC, comprising:

[0007] at least one rotating body, which is a rotating speed controlled object, and has a configurable number of reflective marking areas or speed measurement holes on the surface thereof;

[0008] a proximity photoelectric switch corresponding to the rotating body, which is aligned with the reflective marking areas or speed measurement holes and is used for detecting the rotation information of the rotating body and generating an original pulse signal;

[0009] a programmable logic controller (PLC), wherein a high-speed counter input port of the PLC is electrically connected with a signal output end of each proximity photoelectric switch, and the PLC is internally configured with a pulse preprocessing module, a rotating speed calculation module, a deviation processing module, a control algorithm module and a signal adaptation module; the PLC is configured to:

[0010] (a) performing interference suppression processing on the original pulse signal by the pulse preprocessing module to obtain an effective pulse signal;

[0011] (b) calculating a real-time rotating speed value of the rotating body based on a characteristic parameter of the effective pulse signal by the rotating speed calculation module;

[0012] (c) comparing the real-time rotating speed value with a preset target rotating speed value by the deviation processing module to obtain a rotating speed deviation;

[0013] (d) generating an initial control quantity based on the rotating speed deviation by the control algorithm module, and converting the initial control quantity into a control output signal matched with an execution mechanism by the signal adaptation module;

[0014] at least one execution mechanism, wherein a control end of the execution mechanism is electrically connected with an output port of the PLC, used for receiving the control output signal and adjusting an output parameter of a rotating body driving device, so as to constitute a rotating speed closed-loop control;

[0015] an optional human-machine interface (HMI), which is in communication connection with the PLC and is used for parameter setting, state display and working condition switching.

[0016] Preferably, the following parameters are defined in the process of calculating the real-time rotating speed value by the rotating speed calculation module:

[0017] sampling time , a fixed time interval for collecting the effective pulse signal by the PLC, in seconds;

[0018] Number of valid pulses within the sampling period The output of the pulse preprocessing module, within one sampling time The total number of valid pulses within;

[0019] Number of pulses per revolution of the rotating body The number of pulses generated by the proximity photoelectric switch for each revolution of the rotating body;

[0020] Real-time speed value The actual rotational speed of the rotating body, expressed in revolutions per minute;

[0021] Real-time speed value The calculation formula is:

[0022] ;

[0023] in, The value is the number of valid pulses output by the pulse preprocessing module. The value range is 0.01s to 1s. The value can be a positive integer.

[0024] Preferably, the pulse preprocessing module uses a sliding window filtering algorithm to process the original pulse signal, defining the following parameters:

[0025] Filter window length The number of consecutive sampling periods involved in the filtering calculation. It is a positive integer (≥3);

[0026] No. Number of raw pulses per sampling period Proximity photoelectric switch in the first The number of unprocessed pulses output within each sampling period;

[0027] No. Number of effective pulses per sampling period After sliding window filtering, the first The number of effective pulses per sampling period;

[0028] Valid pulse count The calculation formula is:

[0029] ;

[0030] in, They are respectively the front The number of valid pulses in each sampling period, and the initial sampling period ( )of Equal to the corresponding period The pulse preprocessing module outputs as the number of effective pulses in a sampling period .

[0031] Preferably, the control algorithm module adopts a variable parameter PID control algorithm, and defines the following parameters:

[0032] target speed value , preset target speed of the rotating body, unit: RPM;

[0033] speed deviation , the speed deviation of the th PID operation period, , wherein is the real-time speed value of the th operation period;

[0034] PID operation period , operation interval of the control algorithm module, ;

[0035] basic PID parameters, proportional coefficient , integral coefficient , and derivative coefficient ;

[0036] deviation threshold, is the large deviation threshold, is the small deviation threshold, and ;

[0037] coefficient adjustment factor, is the proportional coefficient amplification factor, , is the derivative coefficient amplification factor, , is the proportional coefficient reduction factor, , is the integral coefficient amplification factor, ;

[0038] The parameter adjustment rule of the variable parameter PID is:

[0039] when , , , ;

[0040] when , ;

[0041] when , ;

[0042] Based on the adjusted PID parameters, the initial control amount The calculation formula is:

[0043] ;

[0044] Wherein, is the rotational speed deviation integral value of the previous operation period, is the rotational speed deviation of the first operation period. Preferably, the signal adaptation module converts the initial control quantity into the input voltage signal of the frequency converter

[0045] , and defines the following parameters: PLC digital quantity output range, is the minimum initial control quantity, taking 0,

[0046] is the maximum initial control quantity, taking 4095; Frequency converter input voltage range: is the minimum input voltage, taking 0V,

[0047] is the maximum input voltage, taking 10V; The calculation formula of the input voltage signal V is:

[0048] ;

[0049] The frequency converter adjusts the output frequency according to the input voltage signal

[0050] , thereby changing the rotational speed of the rotating body driving device, and the output frequency of the frequency converter is linearly related to the input voltage , that is:

[0051] ; Wherein

[0052] is the minimum output frequency of the frequency converter, is the maximum output frequency of the frequency converter. Preferably, when the number of rotating bodies is multiple, the PLC is further provided with a cooperative control module, and the following parameters are defined:

[0053] Main rotating body, any one rotating body set as a reference rotating body, whose real-time rotational speed is

[0054] ;

[0055] Slave rotating body, the remaining rotating bodies, the real-time rotational speed of the first slave rotating body is ; ​​

[0056] Speed ratio coefficient , the first slave rotating body and the preset speed ratio of the main rotating body, , wherein is the target speed of the first slave rotating body, is the target speed of the main rotating body;

[0057] Synchronization deviation , the speed deviation of the first slave rotating body and the main rotating body, ;

[0058] Synchronization deviation threshold , the maximum allowed synchronization deviation;

[0059] Compensation amount , the speed compensation value of the first slave rotating body;

[0060] The control logic of the cooperative control module is:

[0061] When , the target speed of the first slave rotating body is kept unchanged;

[0062] When , the target speed of the first slave rotating body is adjusted, and the adjusted target speed , and , ) is a sign function, 1 when, -1 when;

[0063] The adjusted is used as an input value of the target speed value for the PID control of the slave rotating body.

[0064] Preferably, the HMI can set and store multiple sets of working condition parameters, each set of working condition parameters including target speed , is the working condition number, ; basic PID parameters: ; deviation threshold: ; the PLC is configured with a parameter calling and checking module, and the following parameters are defined:

[0065] Working condition parameter check value , the check value of each set of working condition parameters, used to verify the integrity when reading parameters;

[0066] Modulus , the modulus of the check calculation, taking the value 256;

[0067] check value The calculation formula is:

[0068] ;

[0069] wherein, is a rounding function; when the PLC calls the first group of working condition parameters from the HMI, the check value is recalculated, if , the parameter reading is valid, and , the input values of the real-time rotating speed value and the initial control quantity are taken respectively; if , a parameter error alarm is triggered.

[0070] Preferably, the PLC is further configured with an abnormality detection module for triggering a pulse signal abnormality alarm or a rotating speed overrun alarm, and the following parameters are defined:

[0071] minimum effective pulse threshold , the minimum number of effective pulses in a single sampling period for determining that the signal is normal, which is calculated from the minimum rotating speed of the rotating body and , wherein is the minimum working rotating speed of the rotating body; number of continuous abnormal periods

[0072] , the number of continuous sampling periods for determining the pulse signal abnormality, ;

[0073] rotating speed overrun coefficient : the maximum proportion of the rotating speed allowed to deviate from the target value, ;

[0074] The abnormality detection logic is as follows:

[0075] if the number of effective pulses in continuous sampling periods is all less than , it is determined that the pulse signal is abnormal, and a signal loss alarm is triggered; if the real-time rotating speed value

[0076] exceeds the range of , and the duration exceeds , it is determined that the rotating speed is overrun, and a rotating speed abnormality alarm is triggered; When the abnormality detection module triggers an alarm, an alarm signal is output to the audible and visual alarm synchronously, and the output of the control algorithm module is paused.

[0077] ​​​

[0078] Preferably, the PLC is further configured with a speed prediction module for adjusting the control strategy in advance, defining the following parameters:

[0079] Q, the number of prediction samples, the number of historical sampling periods for speed prediction, ;

[0080] historical speed sequence, , the real-time speed value of the past sampling periods, respectively;

[0081] prediction time , the length of time to be predicted in the future, ;

[0082] predicted speed , the predicted speed after time in the future;

[0083] prediction threshold , the allowable range of the predicted speed;

[0084] The calculation formula of the predicted speed is:

[0085] ;

[0086] wherein, is the speed change amount of the last two sampling periods; if or , the speed prediction module sends a pre-adjustment instruction to the control algorithm module to temporarily amplify the basic proportional coefficient by 1.2~1.5 times to suppress the speed deviation trend in advance.

[0087] Preferably, the PLC reads the operating parameters of the frequency converter through the RS485 communication interface, and the fault self-diagnosis logic of the actuator is based on the following parameters:

[0088] converter rated output current , the rated output current of the frequency converter, unit: ;

[0089] converter real-time output current , the output current of the frequency converter read in the sampling period;

[0090] current deviation , and , the deviation of ;

[0091] current deviation threshold Maximum current deviation allowed, ;

[0092] Fault determination time Time of current deviation exceeding threshold, ;

[0093] The fault self-diagnosis logic is:

[0094] If And the duration exceeds In combination with the abnormal detection result, if the pulse signal abnormality has not been triggered, it is determined that the frequency converter is faulty, the PLC immediately cuts off the control output signal, and triggers the actuator fault alarm; if the pulse signal abnormality has been triggered, it is determined that the root cause of the fault is the rotation body jamming or the photoelectric switch fault, and the PLC executes the shutdown protection program.

[0095] The application provides a rotation speed detection and closed-loop control system based on photoelectric sensing and PLC, which has the following beneficial effects:

[0096] 1. The PLC and the proximity photoelectric switch, which are widely used in the industrial field and have high popularity, are used as core technical components, without the need to rely on expensive special servo controllers, encoders and other equipment, thereby greatly reducing the hardware procurement cost of the system; at the same time, since the PLC and the proximity photoelectric switch are both industrial commonly used standard devices, the market supply is sufficient, and the replacement of spare parts during the later maintenance process is convenient, thereby further reducing the maintenance cost of the system, and the system can be well adapted to ordinary industrial occasions which are sensitive to cost.

[0097] 2. The powerful data processing capability of the PLC is fully utilized, and a complete rotation speed closed-loop control system is constructed in combination with mature control algorithms; the system can obtain the rotation speed information of the rotating equipment in real time, and dynamically adjusts according to the deviation between the actual rotation speed and the target rotation speed, effectively suppresses the rotation speed fluctuation caused by factors such as load change, external interference and the like, ensures that the rotating equipment always stably operates near the target rotation speed, and significantly improves the precision and stability of the rotation speed control, thereby meeting the core needs of rotation speed control in industrial production.

[0098] 3. Relying on the flexible programming characteristics of the PLC, the user can easily adjust the control parameters, control logic and extended functions (such as adding soft start control, multi-section speed switching control, device interlocking protection and the like) by modifying the program according to the needs of different production scenes, without the need to make large-scale changes to the hardware structure; at the same time, the system can conveniently extend the human-machine interface (HMI) and the communication module, not only can realize intuitive parameter setting, state display and other human-machine interaction functions, but also can be connected to the industrial network, realize multi-device collaborative control and remote monitoring and management, and improve the intelligent level of the overall production system.

[0099] 4. The PLC itself has excellent adaptability to industrial environments and can work stably in complex industrial environments such as high temperature, dust, and electromagnetic interference. At the same time, this patent effectively eliminates the influence of external interference on the detection signal by designing signal filtering and processing logic in the PLC program, further improving the system's anti-interference capability. In addition, the system also has a complete abnormality detection and alarm function, which can promptly detect problems such as speed exceeding the limit and signal abnormality and trigger the protection mechanism to ensure long-term stable and safe operation of the system and reduce the risk of equipment failure and downtime. Attached Figure Description

[0100] Fig. 1 This is a schematic diagram of a speed detection and closed-loop control system based on photoelectric sensing and PLC according to the present invention.

[0101] Fig. 2 This is a block diagram illustrating the principle of a single rotating body scenario in a speed detection and closed-loop control system based on photoelectric sensing and PLC, as described in this invention.

[0102] Fig. 3 This is a block diagram illustrating the principle of a multi-rotating body scenario in a rotation speed detection and closed-loop control system based on photoelectric sensing and PLC, as described in this invention. Detailed Implementation

[0103] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0104] like Figs. 1-3 As shown, the present invention provides a technical solution: a speed detection and closed-loop control system based on photoelectric sensing and PLC, comprising:

[0105] At least one rotating body, the rotating body being a rotation speed controlled object, and its surface having a configurable number of reflective marking areas or speed measuring holes;

[0106] A proximity photoelectric switch, corresponding to a rotating body, is aligned with the reflective marking area or speed measuring hole to detect the rotation information of the rotating body and generate a raw pulse signal.

[0107] A programmable logic controller PLC, a high-speed counter input port of the PLC is electrically connected with a signal output end of each proximity photoelectric switch, and the PLC is internally configured with a pulse preprocessing module, a rotating speed calculation module, a deviation processing module, a control algorithm module and a signal adaptation module; the PLC is configured to: (a) perform interference suppression processing on an original pulse signal through the pulse preprocessing module to obtain an effective pulse signal; (b) calculate a real-time rotating speed value of the rotating body based on a characteristic parameter of the effective pulse signal through the rotating speed calculation module; (c) compare the real-time rotating speed value with a preset target rotating speed value through the deviation processing module to obtain a rotating speed deviation; and (d) generate an initial control quantity based on the rotating speed deviation through the control algorithm module, and convert the initial control quantity into a control output signal matched with an executing mechanism through the signal adaptation module;

[0108] At least one executing mechanism, a control end of the executing mechanism is electrically connected with an output port of the PLC, for receiving the control output signal and adjusting an output parameter of the rotating body driving device to constitute a rotating speed closed-loop control;

[0109] An optional human-machine interface HMI, the HMI is in communication connection with the PLC, for parameter setting, state display and working condition switching.

[0110] More specifically, in the process of calculating the real-time rotating speed value by the rotating speed calculation module, the following parameters are defined:

[0111] Sampling time , a fixed time interval for the PLC to collect the effective pulse signal, in seconds;

[0112] Number of effective pulses in a sampling period , a total number of effective pulses output by the pulse preprocessing module in one sampling time ;

[0113] Number of pulses corresponding to one rotation of the rotating body , a number of pulses generated by the proximity photoelectric switch (determined by the number of reflective marking areas or speed measurement holes) when the rotating body rotates one round;

[0114] Real-time rotating speed value , an actual rotating speed of the rotating body, in revolutions per minute;

[0115] The calculation formula of the real-time rotating speed value is:

[0116] ;

[0117] Wherein, the value of the effective pulse number output by the pulse preprocessing module, the value range of the sampling time is 0.01s~1s, the value of the number of pulses corresponding to one rotation of the rotating body is a positive integer.

[0118] The rotational speed calculation module, as the core functional module for obtaining the real-time operating status of the rotating body, precisely defines the sampling time. 1. Number of valid pulses within the sampling period The number of pulses corresponding to each revolution of the rotating body Three types of key parameters, and based on the formula Complete real-time speed value The calculations enabled precise detection and quantification of the rotational speed of the rotating body. Among these, the sampling time... Setting a fixed interval of 0.01s to 1s ensures that the sampling frequency is sufficient to capture the dynamic changes in the rotational speed of the rotating body (e.g., a short interval of 0.01s can avoid speed data lag in high-frequency rotation scenarios), while also ensuring the consistency of the calculation benchmark through the fixed interval; the number of effective pulses within the sampling period The filtered signal output by the pulse preprocessing module effectively eliminates interference signals in the original pulses, avoiding counting deviations caused by noise; the number of pulses per revolution of the rotating body. The number of reflective marking areas or speed measuring holes on the surface of the rotating body is directly determined. For example, when four speed measuring holes are evenly distributed on the surface of the conveyor belt roller... A value of 4 ensures that the rotating body generates 4 pulse signals per revolution, significantly improving the resolution of speed calculation. Through this calculation logic, the system can convert the discrete pulse signals detected by the photoelectric switch into continuous and accurate speed values ​​(unit: revolutions per minute). This provides reliable basic data support for the subsequent deviation processing module to calculate speed deviation and the control algorithm module to generate control quantities. It effectively avoids detection errors caused by signal interference and inconsistent calculation benchmarks in traditional speed detection, ensuring the accuracy and stability of subsequent closed-loop control.

[0119] More specifically, the pulse preprocessing module uses a sliding window filtering algorithm to process the original pulse signal, defining the following parameters:

[0120] Filter window length The number of consecutive sampling periods involved in the filtering calculation. It is a positive integer (≥3);

[0121] No. Number of raw pulses per sampling period Proximity photoelectric switch in the first The number of unprocessed pulses output within each sampling period;

[0122] No. Number of effective pulses per sampling period After sliding window filtering, the first The number of effective pulses per sampling period;

[0123] Valid pulse count The calculation formula is:

[0124] ;

[0125] in, They are respectively the front The number of valid pulses in each sampling period, and the initial sampling period ( )of Equal to the corresponding period The output of the pulse preprocessing module The number of valid pulses within the sampling period The input value.

[0126] The pulse preprocessing module uses a sliding window filtering algorithm to process the raw pulse signal output by the proximity photoelectric switch, by defining the length of the filtering window. ( (a positive integer ≥ 3) the number of original pulses in the i-th sampling period and effective pulse count And based on the formula The filtering calculation was completed, effectively solving the problem of raw pulse signal fluctuations caused by factors such as electromagnetic interference and dust obstruction in industrial environments. Among these factors, the filter window length... The value needs to be determined based on the actual application scenario. For example, in the scenario of fan speed control, if the sampling time... Select Therefore, the filtering calculation needs to include pulse data from 5 consecutive sampling periods, and smooth the instantaneous pulse fluctuations through the averaging of multi-period data; for the initial sampling period ( ), directly convert the original pulse number As the number of effective pulses This ensures the validity of pulse data during the system startup phase. The module outputs... As for the "number of effective pulses within the sampling period" in the subsequent speed calculation module The input value of "" can significantly reduce the interference of noise signals on speed calculation. For example, when the photoelectric switch occasionally outputs abnormal pulses due to dust blockage (such as a sudden increase or decrease in the number of original pulses in a single cycle), the sliding window filtering algorithm can offset the influence of abnormal values ​​by averaging data from multiple cycles, avoiding jumps in speed calculation results, providing a stable and reliable pulse data source for speed detection, and thus ensuring the control accuracy and operational stability of the entire closed-loop control system.

[0127] More specifically, the control algorithm module uses a variable parameter PID control algorithm, defining the following parameters:

[0128] Target speed value , preset rotating body target rotating speed, unit: RPM;

[0129] rotating speed deviation , the th PID operation period rotating speed deviation, , wherein is the real-time rotating speed value of the th operation period;

[0130] PID operation period , the operation interval of the control algorithm module, ;

[0131] basic PID parameters, proportional coefficient , integral coefficient , and differential coefficient ;

[0132] deviation threshold, is the large deviation threshold, is the small deviation threshold, and ;

[0133] coefficient adjustment factor, is the proportional coefficient amplification factor, , is the differential coefficient amplification factor, , is the proportional coefficient reduction factor, , is the integral coefficient amplification factor, ;

[0134] The parameter adjustment rule of the variable parameter PID is:

[0135] when , , , ;

[0136] when , ;

[0137] when , ;

[0138] Based on the adjusted PID parameters, the calculation formula of the initial control quantity (unit: digital quantity, range 0~4095) is:

[0139] ;

[0140] wherein, is the previous The rotational speed deviation integral value of one operation cycle, is the first rotational speed deviation of one operation cycle.

[0141] The control algorithm module adopts a variable parameter PID control algorithm to achieve dynamic and accurate adjustment of the rotational speed of the rotating body. By defining the target rotational speed value , the rotational speed deviation , the PID operation cycle (which is consistent with the sampling time ), the basic PID parameters , the deviation threshold , and the coefficient adjustment factor , and combining the segmented parameter adjustment rule and the initial control amount calculation formula, the problem of poor control effect of the traditional fixed parameter PID in different stages of rotational speed deviation is effectively solved. It can avoid rotational speed overshoot and eliminate static deviation through integration. The initial control amount (output by the algorithm, digital quantity 0~4095) can be directly transmitted to the signal adaptation module to provide accurate control basis for the actuator adjustment. Compared with the traditional PID, it can dynamically optimize the control parameters according to the rotational speed deviation, so that the system maintains excellent control performance under different working conditions, effectively suppresses rotational speed fluctuations, ensures stable operation of the rotating body near the target rotational speed, and meets the core needs of industrial production for rotational speed control precision and stability.

[0142] More specifically, the signal adaptation module converts the initial control amount into an input voltage signal of the frequency converter, and defines the following parameters:

[0143] The PLC digital output range, is the minimum initial control amount, with a value of 0, is the maximum initial control amount, with a value of 4095;

[0144] The frequency converter input voltage range: is the minimum input voltage, with a value of 0V, is the maximum input voltage, with a value of 10V;

[0145] The calculation formula of the input voltage signal V is:

[0146] ;

[0147] The frequency converter adjusts the output frequency according to the input voltage signal , thereby changing the rotational speed of the rotating body driving device (three-phase asynchronous motor), and the output frequency of the frequency converter is in a linear relationship with the input voltage , that is:

[0148] ;

[0149] in This is the minimum output frequency of the frequency converter. This is the maximum output frequency of the frequency converter.

[0150] The signal adapter module, as a key intermediate link connecting the PLC control core and the actuator (frequency converter), defines the range of PLC digital output (…). ), Inverter input voltage range ( ), and based on the formula Complete the initial control quantity The conversion to the inverter input voltage signal V, combined with the inverter output frequency. With input voltage linear relationship formula This achieves precise matching of control signals between PLC digital signals, inverter analog voltages, and motor drive frequencies. For example, when the control algorithm module outputs the maximum initial control quantity... At that time, it can be obtained through conversion. If the frequency converter The corresponding output frequency Drive the three-phase asynchronous motor to its rated speed; if (Middle value), then The motor speed is halved accordingly. This module design not only solves the signal type mismatch problem between the PLC digital output and the inverter analog voltage input, but also ensures a one-to-one correspondence between the control quantity and the motor speed through a linear conversion relationship, avoiding non-linear distortion during signal conversion; simultaneously, it allows for flexible setting... and (e.g., adjust according to the motor's rated frequency) It can be adapted to different models of three-phase asynchronous motors, which greatly improves the system's compatibility with actuators and provides a stable and reliable signal transmission path for subsequent precise adjustment of the rotating body speed through frequency converter, ensuring the effectiveness and flexibility of closed-loop control.

[0151] More specifically, when there are multiple rotating bodies, the PLC is also equipped with a collaborative control module, which defines the following parameters:

[0152] The main rotating body, any rotating body set as the reference, has a real-time rotational speed of... ;

[0153] From the solid of revolution, the remaining solids of revolution, the first The real-time rotational speed of the rotating body is ;

[0154] Speed ​​ratio coefficient , No. A preset speed ratio between the rotating body and the main rotating body. ,in For the first The target rotational speed of the rotating body The target rotational speed of the main rotating body;

[0155] Synchronization Deviation , No. The speed difference between the rotating body and the main rotating body ;

[0156] Synchronization Deviation Threshold The maximum permissible synchronization deviation;

[0157] Compensation amount , No. One rotational speed compensation value from the rotating body;

[0158] The control logic of the collaborative control module is as follows:

[0159] when At that time, maintain the first The target rotational speed of the rotating body constant;

[0160] when At that time, adjust the first The target rotational speed of the rotating body, the adjusted target rotational speed ,and , ) is a symbolic function. Take 1 at time. Take -1 at time;

[0161] Adjusted As the target speed value The input value is used for PID control of the rotating body.

[0162] When used in multi-rotating-body collaborative operation scenarios (such as multi-drum conveyor belts, multi-axis mixing equipment, etc.), the collaborative control module configured in the PLC defines the main rotating body (reference rotating body, real-time rotation speed) by defining the main rotating body (reference rotating body, real-time rotation speed). ), from the rotating body (the first Real-time rotational speed of the rotating body ), speed ratio coefficient (Preset speed ratio, determined by the target speed of the master / slave rotating bodies) Determined), Synchronization Deviation Synchronization Deviation Threshold and compensation amount By combining the control logic of "deviation judgment - target speed adjustment", precise synchronous control among multiple rotating bodies is achieved. For example, in a dual-roller conveyor belt system, the driving roller is set as the main rotating body ( The driven roller is a driven rotating body (preset speed ratio) ,Right now When the driven roller causes an increase in load... Synchronization deviation ,and When the preset threshold is reached, the module uses the formula... , The target rotational speed of the rotating body will be adjusted to 103 RPM, and this will be used as the PID control of the rotating body. Input value, drive the rotational speed of the rotating body to return to synchronization with the main rotating body; if Then keep This module avoids frequent speed fluctuations caused by constant adjustments. It effectively solves the problem of speed asynchrony that easily occurs when multiple rotating bodies are controlled independently (such as material accumulation on the conveyor belt, uneven mixing, etc.). By dynamically adjusting the target speed of the rotating bodies, it ensures that each rotating body always operates in coordination according to the preset speed ratio. At the same time, relying on the reference function of the main rotating body, it reduces the complexity of multi-target control, significantly improves the operational coordination and production stability of multi-rotating body systems, and adapts to the industrial needs of multi-rotating body linkage in fields such as chemical engineering and logistics.

[0163] More specifically, the HMI can set and store multiple sets of operating parameters, each set including the target speed. , For operating condition number, Basic PID parameters: Deviation threshold: The PLC is configured with a parameter call and verification module, defining the following parameters:

[0164] Operating condition parameter verification value The verification value for each set of operating condition parameters is used to verify the integrity of the parameters during reading.

[0165] Modulus The modulus of the verification calculation is 256.

[0166] Check value The calculation formula is:

[0167] ;

[0168] in, This is the rounding function; when the PLC calls the number from the HMI... When setting up operating parameters, recalculate the verification values. ,like , the parameter reading is valid, and are taken as the input values of the real-time rotation speed value and the initial control quantity respectively; if , a parameter error alarm is triggered.

[0169] The human-machine interface (HMI) can set and store multiple sets of working condition parameters according to different production needs, each set of parameters corresponds to a unique working condition number, and contains the target speed of the rotating body, the basic PID parameters (proportion, integral, and differential coefficients) of the control algorithm core, and the deviation threshold required for variable parameter PID adjustment, meeting the parameter switching needs in multiple processes and multiple product production scenarios. To avoid errors caused by communication interference, data loss, and other problems during parameter transmission between the HMI and the PLC, the PLC is specially configured with a parameter calling and verification module. The target speed, basic PID parameters (rounded after amplification to retain accuracy), and deviation threshold in each set of working condition parameters are rounded and summed, and then the remainder is taken to generate a unique working condition parameter verification value. When the PLC needs to call a set of working condition parameters, it will recalculate the verification value according to the same logic. If the two verification values are consistent, it means that the parameter transmission is complete and has not been tampered with. At this time, the set of parameters is transmitted into the speed calculation module (as the target speed reference) and the control algorithm module (as the basis for PID parameters and deviation threshold), ensuring that the system operates stably according to the preset working condition. If the verification values are not consistent, a parameter error alarm is immediately triggered to prevent incorrect parameters from causing speed control errors or equipment operation abnormalities. This design not only simplifies the multi-condition switching operation through the HMI's multiple parameter storage function, but also relies on the verification mechanism to ensure the reliability of parameter transmission and calling, effectively improving the system's adaptability and safety in complex industrial scenarios.

[0170] More specifically, the PLC is also configured with an abnormality detection module for triggering pulse signal abnormality alarms or speed overrun alarms, defining the following parameters:

[0171] The minimum effective pulse threshold is the minimum number of effective pulses within a single sampling period that determines the normality of the signal, calculated from the minimum rotation speed of the rotating body and , where is the minimum working speed of the rotating body;

[0172] The number of consecutive abnormal periods is the number of consecutive sampling periods that determine the abnormality of the pulse signal, ;

[0173] The speed overrun coefficient : the maximum proportion of the allowed deviation of the speed from the target value, ;

[0174] The abnormality detection logic is:

[0175] if the number of valid pulses in consecutive sampling periods is less than , it is determined that the pulse signal is abnormal, and a signal loss alarm is triggered;

[0176] if the real-time speed value is out of the range of , and the duration exceeds (alarm delay time, ), it is determined that the speed is out of limit, and a speed abnormality alarm is triggered;

[0177] When the abnormality detection module triggers an alarm, it synchronously outputs an alarm signal to the audible and visual alarm, and suspends the output of the control algorithm module.

[0178] The abnormality detection module configured by the PLC is a key protection unit for ensuring stable operation of the system, and realizes real-time monitoring of the pulse signal and the speed state by defining three types of core determination basis: the minimum valid pulse threshold is determined by the minimum working speed of the rotating body, the sampling time and the number of pulses corresponding to each revolution, and is used to define the normal range of the pulse signal in a single sampling period; the number of consecutive abnormal periods is set to an integer not less than 3, to avoid misjudgment of abnormality due to single accidental pulse fluctuation; the speed overrun coefficient is set to between 0.1 and 0.2, to clearly define the maximum allowed proportion of the speed deviation from the target value. In actual operation, the module continuously monitors the number of valid pulses output by the pulse preprocessing module, and if the number of valid pulses in consecutive multiple sampling periods is less than the minimum valid pulse threshold, it is determined that the pulse signal is abnormal (such as signal loss caused by photoelectric switch failure, shielding of the reflective marker area, etc.), and a signal loss alarm is immediately triggered. At the same time, the real-time speed output by the speed calculation module is compared with the target speed in real time, and if the real-time speed is out of the allowed deviation range and the duration exceeds the alarm delay time of 2 to 5 seconds (to avoid false alarm due to instantaneous fluctuation), it is determined that the speed is out of limit, and a speed abnormality alarm is triggered. No matter what kind of alarm is triggered, the module will synchronously drive the audible and visual alarm to issue a warning signal, and suspend the output of the control algorithm module, to prevent continuous output of control quantity in abnormal state from causing equipment damage or production accidents. Through the double abnormality determination logic, the design not only timely identifies abnormal problems in signal transmission and speed control, but also forms effective protection through the linkage mechanism of alarm and suspension of control, significantly improving the anti-interference ability and operation safety of the system in complex industrial environments.

[0179] More specifically, the PLC is also configured with a speed prediction module for adjusting the control strategy in advance, defining the following parameters:

[0180] the number of prediction samples Q, the number of historical sampling periods for speed prediction, ; and

[0181] ​a historical rotation speed sequence, , respectively, real-time rotation speed values of the past sampling periods;

[0182] a prediction time , a length of time to be predicted in the future, ;

[0183] a predicted rotation speed , a predicted rotation speed after the future time;

[0184] a prediction threshold , an allowable range of the predicted rotation speed;

[0185] a calculation formula of the predicted rotation speed is as follows:

[0186] ;

[0187] wherein, is a rotation speed change amount of the latest two sampling periods; if or , the rotation speed prediction module sends a pre-adjustment instruction to the control algorithm module, temporarily amplifies the basic proportional coefficient by 1.2-1.5 times, so as to advance the suppression of the rotation speed deviation trend.

[0188] The PLC-configured rotating speed prediction module, as a core functional unit for improving the forward-looking of control, realizes the early judgment of the future rotating speed trend of the rotating body by defining the prediction sample number (not less than 5 historical sampling periods), the prediction time (2 to 5 times of the sampling time) and the prediction rotating speed allowable range (i.e. the prediction threshold). When the module is running, the real-time rotating speed data obtained by the rotating speed calculation module in the past multiple sampling periods will be first called, and the prediction rotating speed after the preset time length in the future is calculated based on the rotating speed change trend of the last two sampling periods; then the prediction rotating speed is compared with the preset allowable range, if the prediction rotating speed exceeds the range (i.e. the future possible rotating speed deviation is predicted), a pre-adjustment instruction is immediately sent to the control algorithm module, and the basic proportional coefficient used to calculate the initial control amount in the control algorithm is temporarily enlarged by 1.2 to 1.5 times. Through this early intervention mechanism, the adjustment strength of the control algorithm can be enhanced when the rotating speed has not actually exceeded the normal range, the rotating speed is suppressed in the direction deviating from the target value in advance, and the problem of excessive rotating speed fluctuation or overshoot in the traditional "after-regulation" mode is avoided; at the same time, the reasonable setting of the prediction sample number and the prediction time not only ensures the accuracy of the prediction result (based on enough historical data), but also ensures the timeliness of the pre-adjustment (matched with the sampling time), effectively improves the response sensitivity of the system to the rotating speed change trend, further guarantees the stability and accuracy of the rotating body rotating speed control, and is especially suitable for industrial scenes (such as the start-stop and load switching process of fan and pump equipment) with easily mutated load and rapidly stable rotating speed.

[0189] More specifically, the PLC reads the operating parameters of the frequency converter through the RS485 communication interface, and the fault self-diagnosis logic of the actuator is based on the following parameters:

[0190] Rated output current of the frequency converter , the rated output current of the frequency converter, in ;

[0191] Real-time output current of the frequency converter , the output current of the frequency converter read in the th sampling period;

[0192] Current deviation , and , the deviation of ;

[0193] Current deviation threshold , the maximum allowed current deviation, ;

[0194] Fault determination time , the time during which the current deviation exceeds the threshold, ;

[0195] The fault self-diagnosis logic is:

[0196] If and the duration exceeds , in combination with the abnormality detection result, if the pulse signal abnormality is not triggered, it is determined that the frequency converter fails, the PLC immediately cuts off the control output signal, and triggers the actuator failure alarm; if the pulse signal abnormality is triggered, it is determined that the root cause of the failure is the rotation body jamming or the photoelectric switch failure, and the PLC executes the stop protection program.

[0197] The PLC reads the running parameters of the actuator (frequency converter) in real time through the RS485 communication interface, and realizes accurate identification and hierarchical processing of the actuator and associated component failures relying on the specially designed fault self-diagnosis logic. The diagnosis logic defines the maximum allowable current deviation (0.3 to 0.5 times the rated output current) and the determination time (1 to 3 seconds) that the current deviation needs to last, based on the rated output current of the frequency converter, to avoid misjudgment of failure due to transient current fluctuation; during operation, the PLC continuously calculates the deviation of the real-time output current of the frequency converter from the rated output current, if the deviation exceeds the allowable range and the duration reaches the determination standard, it will immediately locate the root cause of the failure in combination with the pulse signal state of the abnormality detection module; if the pulse signal abnormality is not triggered, it means that the pulse detection link is normal, and it is determined that the frequency converter itself fails (such as internal component damage, output loop abnormality, etc.), at this time the PLC will immediately cut off the control output signal to prevent the failure from expanding, and trigger the actuator failure alarm to prompt maintenance; if the pulse signal abnormality is triggered, it means that the failure is not from the frequency converter, but from the rotation body jamming (leading to sudden increase of load, abnormal current) or the photoelectric switch failure (indirectly causing control deviation due to signal detection abnormality), at this time the PLC will directly execute the stop protection program to avoid equipment overload damage. The design realizes accurate identification of actuator failure, and can distinguish different root causes of failure and take targeted protection measures through the dual logic of "current deviation monitoring and failure correlation determination", effectively reducing the fault troubleshooting time, reducing the risk of equipment damage, further improving the safety and reliability of system operation, and meeting the needs of fast response and effective protection of actuator failure in industrial scenes.

[0198] Although embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A rotation speed detection and closed-loop control system based on photoelectric sensing and PLC, characterized in that, The application relates to a rotation speed closed-loop control system, which comprises the following parts: at least one rotating body, which is a rotation speed controlled object, and the surface of the rotating body is provided with a configurable number of reflective mark areas or speed measurement holes; proximity photoelectric switches corresponding to the rotating bodies, which are aligned with the reflective mark areas or speed measurement holes and are used for detecting the rotation information of the rotating bodies and generating original pulse signals; a programmable logic controller (PLC), a high-speed counter input port of the PLC is electrically connected with the signal output end of each proximity photoelectric switch, and the PLC is internally provided with a pulse preprocessing module, a rotation speed calculation module, a deviation processing module, a control algorithm module and a signal adaptation module; the PLC is configured to: (a) carry out interference suppression processing on the original pulse signals through the pulse preprocessing module to obtain effective pulse signals; (b) calculate the real-time rotation speed value of the rotating body based on the characteristic parameters of the effective pulse signals through the rotation speed calculation module; (c) compare the real-time rotation speed value with a preset target rotation speed value through the deviation processing module to obtain a rotation speed deviation; (d) generate an initial control quantity based on the rotation speed deviation through the control algorithm module, and convert the initial control quantity into a control output signal matched with an executing mechanism through the signal adaptation module; at least one executing mechanism, a control end of the executing mechanism is electrically connected with an output port of the PLC, is used for receiving the control output signal, and adjusts the output parameter of a rotating body driving device to form a rotation speed closed-loop control; an optional human-machine interface (HMI) which is in communication connection with the PLC and is used for parameter setting, state display and working condition switching.

2. The system according to claim 1, wherein the system is characterized by: In the process of calculating the real-time rotation speed value by the rotation speed calculation module, the following parameters are defined: Sampling time Fixed time interval of PLC to collect valid pulse signal, unit: second Number of effective pulses in a sampling period The total number of effective pulses output by the pulse preprocessing module in a sampling time ​ Pulses per rotation of the rotating body Pulses generated by the proximity optical switch per revolution of the rotating body Real-time rotational speed value Actual rotational speed of the rotating body in revolutions per minute; Real-time rotational speed value The calculation formula is: ； Wherein, The value of the effective pulse number output by the pulse preprocessing module, The value range of the pulse interval is 0.01s~1s, The value of the positive integer is an integer.

3. The system according to claim 2, wherein the system is characterized by: the pulse preprocessing module adopts a sliding window filtering algorithm to process the original pulse signals, and the following parameters are defined: Filter window length the number of consecutive sampling periods involved in the filter computation, is a positive integer (≥ 3); The number of raw pulses in the first sampling period The number of unprocessed pulses output by the proximity photoelectric switch in the first sampling period Number of valid pulses in the first sample period , after sliding window filtering, number of valid pulses in the first sample period Number of effective pulses The formula for calculating is: ； Wherein, The effective pulse number of the initial sampling period is equal to the effective pulse number of the corresponding period. The effective pulse number of the initial sampling period is equal to the effective pulse number of the corresponding period. The effective pulse number of the initial sampling period is equal to the effective pulse number of the corresponding period. The effective pulse number of the initial sampling period is equal to the effective pulse number of the corresponding period. The effective pulse number of the initial sampling period is equal to the effective pulse number of the corresponding period. The effective pulse number of the initial sampling period is equal to the effective pulse number of the corresponding period. The effective pulse number of the initial sampling period is equal to the effective pulse number of the corresponding period.

4. The rotation speed detection and closed-loop control system based on photoelectric sensing and PLC according to claim 3, characterized in that, the control algorithm module adopts a variable parameter PID control algorithm, and the following parameters are defined: Target rotation speed value , a preset rotation body target rotation speed in RPM; speed deviation , the speed deviation of the th PID operation period, wherein is the real-time speed value of the th operation period; PID operation period , control algorithm module operation interval, ; base PID parameters, a proportional coefficient , an integral coefficient , a differential coefficient ; a bias threshold, is a large bias threshold, is a small bias threshold, and ; coefficient adjustment factor, is a proportional coefficient amplification factor, , is a differential coefficient amplification factor, , is a proportional coefficient reduction factor, , is an integral coefficient amplification factor, ; the parameter adjustment rule of the variable parameter PID is that: When time, , , ; When Time, ; When time, ; Based on the adjusted PID parameters, the initial control amount The calculation formula is: ； wherein is the rotational speed deviation integral value of the preceding operational cycle, is the rotational speed deviation of the preceding operational cycle.

5. The optical-electrical sensing and PLC-based rotation speed detection and closed-loop control system according to claim 4, characterized in that, The signal adaptation module converts the initial control quantity into an input voltage signal for the frequency converter defines the following parameters: PLC digital output range, is the minimum initial control amount, taking the value 0, is the maximum initial control amount, taking the value 4095; The frequency converter input voltage range is: The minimum input voltage is 0V, The maximum input voltage is 10V; the calculation formula of an input voltage signal V is that: ； The frequency converter is arranged to change the output frequency in response to the input voltage signal The output frequency is adjusted , thereby changing the rotational speed of the rotating body drive, and the output frequency of the frequency converter is linearly dependent on the input voltage , i.e. ； wherein is the minimum output frequency of the frequency converter, is the maximum output frequency of the frequency converter.

6. The optical-electrical sensing and PLC-based rotation speed detection and closed-loop control system according to claim 5, wherein, when the number of the rotating bodies is multiple, the PLC is further provided with a cooperative control module, and the following parameters are defined: The main rotating body, any one of the rotating bodies set as a reference, has a real-time rotating speed of ; from the rotating body, the remaining rotating body, the first real-time rotational speed of the rotating body; speed ratio coefficient , the first rotary body and the preset rotation speed ratio of the main rotary body, , wherein is the target rotation speed of the first rotary body, is the target rotation speed of the main rotary body; Synchronization deviation , the first rotational speed deviation of the slave rotating body from the main rotating body, ; synchronization deviation threshold , maximum allowed synchronization deviation; Compensation amount , the first rotational speed compensation value; the control logic of the cooperative control module is that: When the first target rotational speed of the slave is kept constant; When the target rotational speed of the first slave is adjusted, the adjusted target rotational speed of the first slave is , ) is a sign function, 1 when -1 when adjusted target rotational speed value input value for the PID control from the rotating body.

7. The optical-electrical sensing and PLC-based rotation speed detection and closed-loop control system according to claim 6, characterized in that, The HMI can set and store multiple groups of working condition parameters, each group of working condition parameters including a target rotating speed , is a working condition number, ; basic PID parameters: ; deviation threshold: ; the PLC is configured with a parameter calling and checking module, and the following parameters are defined: Working condition parameter check value Check value of each group of working condition parameters, used for verifying integrity when reading parameters modulus , the modulus of the check calculation, takes the value 256; check value The calculation formula is: ； wherein, is a rounding function; when the PLC calls the first group of working condition parameters from the HMI, the check value is recalculated , if , the parameter reading is valid, and the input values of the real-time rotation speed value and the initial control quantity are respectively taken; if , a parameter error alarm is triggered.

8. The optical-electrical sensing and PLC-based rotation speed detection and closed-loop control system according to claim 7, characterized in that, the PLC is further provided with an abnormality detection module which is used for triggering pulse signal abnormality alarm or rotation speed overrun alarm, and the following parameters are defined: Minimum effective pulse threshold , the minimum effective pulse number of the determination signal in a single sampling period, is calculated by the minimum rotating speed of the rotating body and , , wherein is the minimum working rotating speed of the rotating body; Number of consecutive abnormal cycles , the number of consecutive sampling periods in which the pulse signal is abnormal, ; coefficient of overspeeding : maximum proportion by which the rotational speed is allowed to deviate from the target value, ; the abnormality detection logic is that: If consecutive The number of effective pulses in a sampling period Are all less than Then determine that the pulse signal is abnormal, trigger signal loss alarm; If the real-time speed value Exceeding The range, and the duration exceeds If the speed exceeds the limit, an abnormal speed alarm will be triggered. when the abnormality detection module triggers the alarm, an alarm signal is synchronously output to a sound-light alarm device, and the output of the control algorithm module is paused.

9. The optical-electrical sensing and PLC-based rotation speed detection and closed-loop control system according to claim 8, wherein, The PLC is further provided with a rotation speed prediction module which is used for adjusting the control strategy in advance, and the following parameters are defined: a number of prediction samples Q, a number of historical sampling periods for speed prediction, ; a historical speed sequence, the real-time speed value of the past sampling periods, respectively; forecast time , the length of time in the future for which a forecast is required, ; predicted rotational speed , future predicted rotational speed after the time Prediction threshold , a permissible range of the predicted rotational speed; Predicted speed The calculation formula is: ； Wherein, is the change of the rotating speed in the last two sampling periods; if or , the rotating speed prediction module sends a pre-adjustment instruction to the control algorithm module to increase the basic proportional coefficient temporarily by 1.2-1.5 times to suppress the rotating speed deviation trend in advance.

10. The optical-electrical sensing and PLC-based rotation speed detection and closed-loop control system according to claim 9, wherein, the PLC reads the running parameters of a frequency converter through an RS485 communication interface, and the fault self-diagnosis logic of the executing mechanism is based on the following parameters: Rated output current of the frequency converter , the rated output current of the frequency converter, in Amps; Variable frequency drive real-time output current , the variable frequency drive output current read at the th sample period; current deviation , with deviation, ; current deviation threshold , maximum current deviation allowed, ; fault determination time , the time during which the current deviation exceeds the threshold value, ; the fault self-diagnosis logic is that: If and the duration exceeds , in combination with the abnormal detection result, if the pulse signal is not triggered abnormally, it is determined that the frequency converter is faulty, the PLC immediately cuts off the control output signal and triggers the actuator fault alarm; if the pulse signal has been triggered abnormally, it is determined that the root cause of the fault is the rotation body jamming or the photoelectric switch fault, and the PLC executes the stop protection program.

Images