Cylinder abnormity detection circuit based on PLC

Abstract

The utility model discloses an air cylinder abnormity detection circuit based on a PLC. The air cylinder abnormity detection circuit comprises a start button, a stop button, a first magnetic sensor, a second magnetic sensor, a first servo controller, a first reversing valve, a first air cylinder, a first direct-current power source, the PLC and a touch screen. The real-time measurement of the actual time of the cylinder extension action and the actual time of the cylinder retraction action can be automatically carried out in the extension and retraction processes of a cylinder piston rod when equipment works; and when the actual time of the cylinder extension action is longer than the limit time of the cylinder extension action or the actual time of the cylinder retraction action is longer than the limit time of the cylinder retraction action, shutdown is automatically carried out and an alarm is given to remind that the cylinder action is abnormal, so that the product quality is ensured and other accidents are avoided.

Description

Technical Field

[0001] The utility model relates to the field of cylinder abnormality detection, in particular to a cylinder abnormality detection circuit based on PLC. Background Art

[0002] Most of the automated equipment in the factory uses pneumatic cylinders, which rely on controlling the power on and off of the reversing valve coil to control the extension and retraction of the cylinder piston rod. However, after long-term use, the sealing ring on the cylinder piston will be damaged and internal gas will be generated. The internal gas in the cylinder cannot be discovered in time, which prolongs the extension and retraction time of the cylinder piston rod. The pressure of the cylinder is reduced when it is extended to press the product, resulting in quality accidents such as product pressing or poor sealing. Due to the extension of the overall action cycle time of the cylinder, the actual production capacity of the production equipment will also decrease. Summary of the invention

[0003] In order to overcome the defects of the prior art, the technical problem to be solved by the utility model is to provide a cylinder abnormality detection circuit based on PLC, which can automatically perform real-time measurement of the actual time of cylinder extension and the actual time of cylinder retraction during the extension and retraction of the cylinder piston rod when the equipment is working. When the actual time of the cylinder extension is greater than the limit time of the cylinder extension or when the actual time of the cylinder retraction is greater than the limit time of the cylinder retraction, the machine will automatically shut down and alarm to prompt the abnormal cylinder action, thereby ensuring product quality and avoiding other accidents.

[0004] In order to achieve the above-mentioned object, the utility model provides the following technical solutions: a cylinder abnormality detection circuit based on PLC includes a start button, a stop button, a first magnetic sensor, a second magnetic sensor, a first servo controller, a first reversing valve, a first cylinder, a first DC power supply, a programmable controller, and a touch screen;

[0005] The lower end of the start button is electrically connected to the input side X1 end of the programmable controller, the lower end of the stop button is electrically connected to the input side X2 end of the programmable controller, the lower end of the first magnetic sensor is electrically connected to the input side X3 end of the programmable controller, the lower end of the second magnetic sensor is electrically connected to the input side X4 end of the programmable controller, the upper end of the start button, the upper end of the stop button, the upper end of the first magnetic sensor, the upper end of the second magnetic sensor, the upper end of the first photoelectric sensor, and the 24V end of the touch screen are electrically connected to the 24V end of the first DC power supply at the same time, and the input side S / S end of the programmable controller and the 0V end of the touch screen are electrically connected to the 0V end of the first DC power supply at the same time;

[0006] The output side Y1 end of the programmable controller is electrically connected to the upper end of the first servo controller, the output side Y2 end of the programmable controller is electrically connected to the first end of the coil of the first reversing valve, the output side COM1 end of the programmable controller is electrically connected to the 24V end of the first DC power supply, and the lower end of the first servo controller and the second end of the coil of the first reversing valve (YV1) are electrically connected to the 0V end of the first DC power supply at the same time;

[0007] The power supply terminals L and N of the programmable controller are electrically connected to the phase line L and the neutral line N of the power supply respectively;

[0008] The P port of the first reversing valve is an air source inlet interface of compressed air, the A port of the first reversing valve is connected to the upper left air circuit interface of the first cylinder, and the B port of the first reversing valve is connected to the lower left air circuit interface of the first cylinder;

[0009] The first cylinder is a piston-built-in magnetic ring cylinder, the first magnetic sensor is an upper limit magnetic sensor of the first cylinder, and the second magnetic sensor is a lower limit magnetic sensor of the first cylinder;

[0010] The touch screen communicates with the programmable controller via RS485, and the touch screen displays abnormal alarm information diagnosed by the programmable controller;

[0011] The touch screen is provided with a cylinder action time test button M11, a test start button M1, and a test stop button M0, and the touch screen is provided with a cylinder extension action test standard time D1, a cylinder retraction action test standard time D0, a cylinder extension action allowable deviation time setting D7, a cylinder retraction action allowable deviation time setting D8, a cylinder extension action limit time D11, a cylinder retraction action limit time D15, a cylinder extension action actual time D21, and a cylinder retraction action actual time D20;

[0012] The pressure of compressed air is normal. When the equipment stops, the first magnetic sensor detects that the piston rod of the first cylinder has been fully retracted upward. The input indicator light on the input side X3 of the programmable controller is on, and the input indicator light on the input side X4 is off. After pressing the cylinder action time test button M11 on the touch screen, press the test start button M1, the output side Y2 of the programmable controller is connected to the COM1 end, and the two ends of the coil of the first reversing valve obtain a 24V voltage. The piston rod of the first cylinder extends downward. After the second magnetic sensor detects that the piston rod of the first cylinder has been fully extended downward, the internal program of the programmable controller stores the measured cylinder extension action test standard time in the cylinder extension action test standard time D1, and the cylinder is extended. The action test standard time D1 and the cylinder extension action allowable deviation time setting D7 are summed and stored in the cylinder extension action limit time D11. At this time, the test stop button M0 on the touch screen is pressed again, the output side Y2 end of the programmable controller and the COM1 end are turned off, the two ends of the coil of the first reversing valve lose the 24V voltage, the piston rod of the first cylinder retracts upward, and after the second magnetic sensor detects that the piston rod of the first cylinder has been completely retracted upward, the internal program of the programmable controller stores the measured cylinder retraction action test standard time in the cylinder retraction action test standard time D0, and sums the cylinder retraction action test standard time display D0 and the cylinder retraction action allowable deviation time setting D8 and stores them in the cylinder extension action limit time D15;

[0013] The pressure of compressed air is normal. After the cylinder action time test has been completed, press the start button and the equipment enters the automatic operation state. The programmable controller sends a pulse to the first servo controller through the output side Y1 end. After the pulse is sent, the output side Y2 end of the programmable controller is connected to the COM1 end, and the two ends of the coil of the first reversing valve obtain a 24V voltage. The piston rod of the first cylinder extends downward, and the timing of the cylinder extension action time starts at the same time. After the second magnetic sensor detects that the piston rod of the first cylinder has been fully extended downward, the internal program of the programmable controller immediately stores the current timing time of the cylinder extension action in the actual time D21 of the cylinder extension action, and compares the actual time D21 of the cylinder extension action with the limit time D11 of the cylinder extension action. When the actual time D21 of the cylinder extension action is reached, the cylinder extension action limit time D11 is reached. 21 is greater than the cylinder extension action limit time D11, an abnormal alarm is automatically issued to prompt shutdown; after the piston rod of the first cylinder completes the downward extension action, the output side Y2 end of the programmable controller is disconnected from the COM1 end, the coil ends of the first reversing valve lose the 24V voltage, the piston rod of the first cylinder retracts upward, and the timing of the cylinder retraction action time starts at the same time. After the second magnetic sensor detects that the piston rod of the first cylinder has been completely retracted upward, the internal program of the programmable controller immediately stores the current timing time of the cylinder retraction action into the actual cylinder retraction action time D20, and compares the actual cylinder retraction action time D20 with the cylinder retraction action limit time D15. When the actual cylinder retraction action time D20 is greater than the cylinder retraction action limit time D15, an abnormal alarm is automatically issued to prompt shutdown.

[0014] In the above-mentioned PLC-based cylinder abnormality detection circuit, the first servo controller is electrically connected to the servo motor. The servo motor runs when the programmable controller sends pulses to the first servo controller through the output side Y1 end, and the servo motor stops running after sending the pulses to the first servo controller.

[0015] Compared with the prior art, the beneficial effect of the utility model is that it can automatically measure the actual time of cylinder extension and the actual time of cylinder retraction in real time during the extension and retraction of the cylinder piston rod when the equipment is working. When the actual time of cylinder extension is greater than the limit time of cylinder extension or when the actual time of cylinder retraction is greater than the limit time of cylinder retraction, the machine will automatically shut down and alarm to prompt abnormal cylinder movement, thereby ensuring product quality and avoiding other accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a structural schematic diagram of a cylinder abnormality detection circuit based on PLC provided by an embodiment of the utility model;

[0018] Figure 2 It is a PLC input and output schematic diagram of a PLC-based cylinder abnormality detection circuit provided by an embodiment of the utility model;

[0019] Figure 3 It is a PLC program schematic diagram for determining the standard time of cylinder extension action test and the standard time of cylinder retraction action test based on a cylinder abnormality detection circuit provided by an embodiment of the utility model;

[0020] Figure 4 It is a schematic structural diagram of a cylinder abnormality detection circuit based on PLC provided by the embodiment of the utility model, in which the first cylinder piston rod is fully retracted upward after the two ends of the first reversing valve coil lose the 24V voltage;

[0021] Figure 5 It is a structural schematic diagram of a cylinder abnormality detection circuit based on PLC provided by an embodiment of the utility model, in which the first cylinder piston rod is fully extended downward after the two ends of the first reversing valve coil obtain a 24V voltage;

[0022] Reference numerals

[0023] Start button SB1, stop button SB2, first magnetic sensor SQ1, second magnetic sensor SQ2, first servo controller M, first reversing valve YV1, first cylinder QG1, first DC power supply V1, programmable controller PLC1, touch screen HMI1. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments. Similar component numbers in the drawings represent similar components. Obviously, the embodiments to be described below are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0025] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0026] It should also be understood that the terms used in this utility model embodiment specification are only for the purpose of describing specific embodiments and are not intended to limit the utility model embodiments. As used in the utility model embodiment specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0027] Example

[0028] like Figures 1 to 5 As shown, the utility model is a cylinder abnormality detection circuit based on PLC, including a start button SB1, a stop button SB2, a first magnetic sensor SQ1, a second magnetic sensor SQ2, a first servo controller M, a first reversing valve YV1, a first cylinder QG1, a first DC power supply V1, a programmable controller PLC1, and a touch screen HMI1;

[0029] The lower end of the start button SB1 is electrically connected to the input side X1 end of the programmable controller PLC1, the lower end of the stop button SB2 is electrically connected to the input side X2 end of the programmable controller PLC1, the lower end of the first magnetic sensor SQ1 is electrically connected to the input side X3 end of the programmable controller PLC1, the lower end of the second magnetic sensor SQ2 is electrically connected to the input side X4 end of the programmable controller PLC1, the upper end of the start button SB1, the upper end of the stop button SB2, the upper end of the first magnetic sensor SQ1, the upper end of the second magnetic sensor SQ2, the upper end of the first photoelectric sensor PH1, and the 24V end of the touch screen HMI1 are electrically connected to the 24V end of the first DC power supply V1 at the same time, and the input side S / S end of the programmable controller PLC1 and the 0V end of the touch screen HMI1 are electrically connected to the 0V end of the first DC power supply V1 at the same time;

[0030] The output side Y1 end of the programmable controller PLC1 is electrically connected to the upper end of the first servo controller M, the output side Y2 end of the programmable controller PLC1 is electrically connected to the first end of the coil of the first reversing valve YV1, the output side COM1 end of the programmable controller PLC1 is electrically connected to the 24V end of the first DC power supply V1, and the lower end of the first servo controller M and the second end of the coil of the first reversing valve YV1 are electrically connected to the 0V end of the first DC power supply V1 at the same time;

[0031] The power supply terminals L and N of the programmable controller PLC1 are electrically connected to the phase line L and the neutral line N of the power supply respectively;

[0032] The first reversing valve YV1P port is the air source inlet interface of the compressed air, the first reversing valve YV1A port is connected to the upper left air circuit interface of the first cylinder QG1, and the first reversing valve YV1B port is connected to the lower left air circuit interface of the first cylinder QG1;

[0033] The first cylinder QG1 is a piston-built-in magnetic ring cylinder, the first magnetic sensor SQ1 is the upper limit magnetic sensor of the first cylinder QG1, and the second magnetic sensor SQ2 is the lower limit magnetic sensor of the first cylinder QG1;

[0034] RS485 communication between the touch screen HMI1 and the programmable controller PLC1, the touch screen HMI1 displays the abnormal alarm information diagnosed by the programmable controller PLC1;

[0035] The touch screen HMI1 screen is respectively provided with a cylinder action time test button M11, a test start button M1, and a test stop button M0; the touch screen HMI1 screen is respectively provided with a cylinder extension action test standard time D1, a cylinder retraction action test standard time D0, a cylinder extension action allowable deviation time setting D7, a cylinder retraction action allowable deviation time setting D8, a cylinder extension action limit time D11, a cylinder retraction action limit time D15, a cylinder extension action actual time D21, and a cylinder retraction action actual time D20;

[0036] The pressure of compressed air is normal. When the equipment stops, the first magnetic sensor SQ1 detects that the piston rod of the first cylinder QG1 has been fully retracted upward. The input indicator light at the input side X3 end of the programmable controller PLC1 is on, and the input indicator light at the input side X4 end is off. After pressing the cylinder action time test button M11 on the touch screen HMI1 screen, press the test start button M1, the output side Y2 end of the programmable controller PLC1 is connected to the COM1 end, and the two ends of the coil of the first reversing valve YV1 obtain a 24V voltage. The piston rod of the first cylinder QG1 extends downward. After the second magnetic sensor SQ2 detects that the piston rod of the first cylinder QG1 has been fully extended downward, the internal program of the programmable controller PLC1 stores the measured cylinder extension action test standard time in the cylinder extension action test standard time D1. The cylinder extension action test standard time D1 and the cylinder extension action allowable deviation time setting D7 are summed and stored in the cylinder extension action limit time D11. At this time, the test stop button M0 on the touch screen HMI1 screen is pressed again, the output side Y2 end of the programmable controller PLC1 and the COM1 end are turned off, the two ends of the coil of the first reversing valve YV1 lose the 24V voltage, the piston rod of the first cylinder QG1 retracts upward, and the second magnetic sensor SQ2 detects that the piston rod of the first cylinder QG1 has been completely retracted upward. Then, the internal program of the programmable controller PLC1 stores the measured cylinder retraction action test standard time in the cylinder retraction action test standard time D0, and sums the cylinder retraction action test standard time display D0 and the cylinder retraction action allowable deviation time setting D8 and stores them in the cylinder extension action limit time D15;

[0037] The pressure of compressed air is normal. After the cylinder action time test has been completed, press the start button SB1, the equipment enters the automatic operation state, and the programmable controller PLC1 sends a pulse to the first servo controller M through the output side Y1 end. After the pulse is sent, the output side Y2 end of the programmable controller PLC1 is connected to the COM1 end, and the two ends of the coil of the first reversing valve YV1 obtain a 24V voltage. The piston rod of the first cylinder QG1 extends downward, and the timing of the cylinder extension action time starts at the same time. After the second magnetic sensor SQ2 detects that the piston rod of the first cylinder QG1 has been fully extended downward, the internal program of the programmable controller PLC1 immediately stores the current timing time of the cylinder extension action in the actual cylinder extension action time D21, and compares the actual cylinder extension action time D21 with the cylinder extension action limit time D11. When the cylinder extension action is actually When the time D21 is greater than the cylinder extension action limit time D11, an abnormal alarm is automatically issued to prompt shutdown; after the piston rod of the first cylinder QG1 completes the downward extension action, the output side Y2 end of the programmable controller PLC1 is disconnected from the COM1 end, the two ends of the coil of the first reversing valve YV1 lose the 24V voltage, the piston rod of the first cylinder QG1 retracts upward, and the timing of the cylinder retraction action time starts at the same time. After the second magnetic sensor SQ2 detects that the piston rod of the first cylinder QG1 has been completely retracted upward, the internal program of the programmable controller PLC1 immediately stores the current timing time of the cylinder retraction action in the actual cylinder retraction action time D20, and compares the actual cylinder retraction action time D20 with the cylinder retraction action limit time D15. When the actual cylinder retraction action time D20 is greater than the cylinder retraction action limit time D15, an abnormal alarm is automatically issued to prompt shutdown.

[0038] Specifically, the first servo controller M is electrically connected to the servo motor. The servo motor runs when the programmable controller PLC1 sends pulses to the first servo controller M through the output side Y1 terminal. After sending the pulses to the first servo controller M, the servo motor stops running.

[0039] Now we will further explain the usage of the PLC-based cylinder abnormality detection circuit:

[0040] The pressure of compressed air is normal. When the equipment stops, the first magnetic sensor SQ1 detects that the piston rod of the first cylinder QG1 has been fully retracted upward. The input indicator light at the input side X3 end of the programmable controller PLC1 is on, and the input indicator light at the input side X4 end is off. After pressing the cylinder action time test button M11 on the touch screen HMI1 screen, press the test start button M1, the output side Y2 end of the programmable controller PLC1 is connected to the COM1 end, and the two ends of the coil of the first reversing valve YV1 obtain a 24V voltage. The piston rod of the first cylinder QG1 extends downward. After the second magnetic sensor SQ2 detects that the piston rod of the first cylinder QG1 has been fully extended downward, the internal program of the programmable controller PLC1 stores the measured cylinder extension action test standard time in the cylinder extension action test standard time D1. The cylinder extension action test standard time D1 and the cylinder extension action allowable deviation time setting D7 are summed and stored in the cylinder extension action limit time D11. At this time, the test stop button M0 on the touch screen HMI1 screen is pressed again, the output side Y2 end of the programmable controller PLC1 and the COM1 end are turned off, the two ends of the coil of the first reversing valve YV1 lose the 24V voltage, the piston rod of the first cylinder QG1 retracts upward, and the second magnetic sensor SQ2 detects that the piston rod of the first cylinder QG1 has been completely retracted upward. Then, the internal program of the programmable controller PLC1 stores the measured cylinder retraction action test standard time in the cylinder retraction action test standard time D0, and sums the cylinder retraction action test standard time display D0 and the cylinder retraction action allowable deviation time setting D8 and stores them in the cylinder extension action limit time D15;

[0041] The pressure of compressed air is normal. After the cylinder action time test has been completed, press the start button SB1, and the equipment enters the automatic operation state. The programmable controller PLC1 sends a pulse to the first servo controller M through the output side Y1 end. The servo motor runs during the process of the programmable controller PLC1 sending the pulse to the first servo controller M through the output side Y1 end. After the pulse sending is completed, the servo motor stops running. The output side Y2 end of the programmable controller PLC1 is connected to the COM1 end, and the two ends of the coil of the first reversing valve YV1 obtain a 24V voltage. The piston rod of the first cylinder QG1 extends downward, and the timing of the cylinder extension action time starts at the same time. After the second magnetic sensor SQ2 detects that the piston rod of the first cylinder QG1 has been fully extended downward, the internal program of the programmable controller PLC1 immediately stores the current timing time of the cylinder extension action in the actual time D21 of the cylinder extension action, and compares the actual time D21 of the cylinder extension action with the limit time D11 of the cylinder extension action. When the cylinder extension action actual time D21 is reached, the cylinder extension action limit time D11 is reached. When the time D21 is greater than the cylinder extension action limit time D11, an abnormal alarm of "the actual time of the cylinder extension action exceeds the limit time (cylinder blowby)" is automatically issued to prompt a shutdown; after the downward extension action of the piston rod of the first cylinder QG1 is completed, the output side Y2 end of the programmable controller PLC1 and the COM1 end are turned off, the two ends of the coil of the first reversing valve YV1 lose the 24V voltage, the piston rod of the first cylinder QG1 retracts upward, and the timing of the cylinder retraction action time starts at the same time. After the second magnetic sensor SQ2 detects that the piston rod of the first cylinder QG1 has been completely retracted upward, the internal program of the programmable controller PLC1 immediately stores the current timing time of the cylinder retraction action in the actual time D20 of the cylinder retraction action, and compares the actual time D20 of the cylinder retraction action with the limit time D15 of the cylinder retraction action. When the actual time D20 of the cylinder retraction action is greater than the limit time D15 of the cylinder retraction action, an abnormal alarm of "the actual time of the cylinder extension action exceeds the limit time (cylinder blowby)" is automatically issued to prompt a shutdown.

[0042] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0043] The above is a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the utility model, and these modifications or replacements should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A cylinder abnormality detection circuit based on PLC, characterized in that: The PLC-based cylinder abnormality detection circuit includes: A start button (SB1), a stop button (SB2), a first magnetic sensor (SQ1), a second magnetic sensor (SQ2), a first servo controller (M), a first reversing valve (YV1), a first cylinder (QG1), a first DC power supply (V1), a programmable controller (PLC1), and a touch screen (HMI1); The lower end of the start button (SB1) is electrically connected to the input side X1 end of the programmable controller (PLC1), the lower end of the stop button (SB2) is electrically connected to the input side X2 end of the programmable controller (PLC1), the lower end of the first magnetic sensor (SQ1) is electrically connected to the input side X3 end of the programmable controller (PLC1), the lower end of the second magnetic sensor (SQ2) is electrically connected to the input side X4 end of the programmable controller (PLC1), the upper end of the start button (SB1), the upper end of the stop button (SB2), the upper end of the first magnetic sensor (SQ1), the upper end of the second magnetic sensor (SQ2), the upper end of the first photoelectric sensor (PH1), and the 24V end of the touch screen (HMI1) are electrically connected to the 24V end of the first DC power supply (V1) at the same time, and the input side S / S end of the programmable controller (PLC1) and the 0V end of the touch screen (HMI1) are electrically connected to the 0V end of the first DC power supply (V1) at the same time; The output side Y1 end of the programmable controller (PLC1) is electrically connected to the upper end of the first servo controller (M), the output side Y2 end of the programmable controller (PLC1) is electrically connected to the first end of the coil of the first reversing valve (YV1), the output side COM1 end of the programmable controller (PLC1) is electrically connected to the 24V end of the first DC power supply (V1), and the lower end of the first servo controller (M) and the second end of the coil of the first reversing valve (YV1) are electrically connected to the 0V end of the first DC power supply (V1) at the same time; The power supply terminals L and N of the programmable controller (PLC1) are electrically connected to the phase line L and the neutral line N of the power supply respectively; The P port of the first reversing valve (YV1) is an air source inlet interface for compressed air, the A port of the first reversing valve (YV1) is connected to the upper left air circuit interface of the first cylinder (QG1), and the B port of the first reversing valve (YV1) is connected to the lower left air circuit interface of the first cylinder (QG1); The first cylinder (QG1) is a piston-built-in magnetic ring cylinder, the first magnetic sensor (SQ1) is an upper limit magnetic sensor of the first cylinder (QG1), and the second magnetic sensor (SQ2) is a lower limit magnetic sensor of the first cylinder (QG1); The touch screen (HMI1) communicates with the programmable controller (PLC1) via RS485, and the touch screen (HMI1) displays abnormal alarm information diagnosed by the programmable controller (PLC1); The touch screen (HMI1) is respectively provided with a cylinder action time test button M11, a test start button M1, and a test stop button M0; the touch screen (HMI1) is respectively provided with a cylinder extension action test standard time D1, a cylinder retraction action test standard time D0, a cylinder extension action allowable deviation time setting D7, a cylinder retraction action allowable deviation time setting D8, a cylinder extension action limit time D11, a cylinder retraction action limit time D15, a cylinder extension action actual time D21, and a cylinder retraction action actual time D20.

2. The PLC-based cylinder abnormality detection circuit according to claim 1 is characterized in that: The first servo controller (M) is electrically connected to the servo motor. The servo motor runs when the programmable controller (PLC1) sends pulses to the first servo controller (M) through the output side Y1 end, and the servo motor stops running after sending the pulses to the first servo controller (M).

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