An electrical control system for a column changing machine based on PLC

Abstract

The present invention discloses an electrical control system for a material column changing machine based on PLC, including a starting module, a PLC control unit and a hydraulic system; by controlling the start and close of the starting module, the PLC control unit collects the start and close signals of the starting module, and transmits the signals to the pump station motor of the hydraulic system through the output signal of the PLC control unit; the pump station motor selects high and low speed states according to the output signal, and drives the actuator of the hydraulic system to perform actions; the power on and power off control of multiple solenoid valve combinations can be realized according to the high and low speed hydraulic truth tables set in the PLC control unit, thereby realizing the motion control of the pump station motor and the actuator. The present invention provides an electrical control system for a material column changing machine based on PLC, which improves the control degree of the material column machine and improves the stability of the control of the material column machine by cooperating with the PLC control unit, the control device and the hydraulic system.

Description

Technical Field

[0001] The invention relates to the field of electrical control systems for column material machines, and in particular to the field of electrical control systems for ring column material machines based on PLC. Background Art

[0002] The column feeder mainly relies on hydraulic drive to work, adopts hydraulic pump to provide power for the hydraulic system, and adopts reversing solenoid valve to drive various actions; the hydraulic system performs action control according to the hydraulic principle, and realizes various control actions by connecting and disconnecting the main valve and reversing valve; but during control, in the process of signal transmission of various action buttons, due to the need for the control unit with complex wiring circuit to process and output multiple signals, the signal transmission will be not stable enough, affecting the execution of the control equipment action; therefore, it is necessary to optimize the control of the existing column feeder system. Summary of the invention

[0003] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides an electrical control system for a material column changing machine based on PLC, which improves the control degree of the material column machine and improves the stability of the control of the material column machine by coordinating the PLC control unit with the control equipment and the hydraulic system.

[0004] Technical solution: To achieve the above purpose, the technical solution of the present invention is as follows:

[0005] A PLC-based electrical control system for a material exchange column machine comprises a start module, a PLC control unit and a hydraulic system; by controlling the start and close of the start module, the PLC control unit collects the start and close signals of the start module, and transmits the signals to the pump station motor of the hydraulic system through the output signal of the PLC control unit; the pump station motor selects high and low speed states according to the output signal, and drives the actuator of the hydraulic system to perform actions; the power on and power off control of a plurality of solenoid valve combinations can be realized according to the high and low speed hydraulic truth tables set in the PLC control unit, thereby realizing the action control of the pump station motor and the actuator.

[0006] Furthermore, the high-speed and low-speed truth tables include a high-speed hydraulic truth table and a low-speed hydraulic truth table; the hydraulic system uses four solenoid valves to configure the main valve, which are 1YA, 2YA, 3YA and 4YA; 1YA and 2YA are in a low-speed state, and 3YA and 4YA are in a high-speed state; the solenoid valves of the actuators are paired with 1YA, 2YA, 3YA and 4YA, respectively, to form a high-speed hydraulic truth table and a low-speed hydraulic truth table.

[0007] Furthermore, the actuator includes an auxiliary arm, and the solenoid valves of the auxiliary arm are 5YA and 6YA; when the auxiliary arm performs an auxiliary arm rising action in a high-speed state, the output signal of the PLC control unit is to connect 3YA and 5YA; when the auxiliary arm performs an auxiliary arm descending action in a high-speed state, the output signal of the PLC control unit is to connect 4YA and 6YA; when the auxiliary arm performs an auxiliary arm rising action in a low-speed state, the output signal of the PLC control unit is to connect 1YA and 5YA; when the auxiliary arm performs an auxiliary arm descending action in a low-speed state, the output signal of the PLC control unit is to connect 2YA and 6YA.

[0008] Furthermore, an oil cylinder is arranged in the pump station motor; forward conduction and reverse conduction of the oil cylinder are realized by a reversing solenoid valve; when oil is input into the rod chamber, the oil cylinder retracts; when oil is input into the rodless chamber, the oil cylinder extends; regulating valves are arranged at the oil passage ports of the rodless chamber and the rod chamber, and the speed and pressure of extension and retraction of the oil cylinder are adjusted by the regulating valves.

[0009] Furthermore, a convex ring is fixedly arranged on the inner wall of the oil-passing port in an annular direction; an annular groove is opened in the inner wall of the convex ring in an annular direction, and a plurality of adjustment plates are arranged in an annular groove; one end of the bottom of the adjustment plate is hingedly arranged with the bottom of the annular groove, and an elastic member is sandwiched between the other end of the bottom of the adjustment plate and the bottom of the annular groove; one end of the adjustment plate corresponding to the elastic member is tilted, and the tilting protrudes from the annular groove; adjacent adjustment plates are staggered and partially overlapped; V-shaped grooves are formed between adjacent tiltings;

[0010] The regulating valve includes a rotating ring, which is slidably arranged on one side of the convex ring, and a driving device on the side wall of the convex ring drives the rotating ring to rotate; a pressure rod is fixedly provided on the inner wall of the rotating ring, and the pressure rod is perpendicular to the rotating ring, and the pressure rod passes through a V-shaped groove; the rotating ring drives the pressure rod to rotate, and the pressure rod moves in the direction of the elastic member, and the pressure rod presses the raised adjusting plate to embed it into the ring groove, thereby realizing the adjustment of the diameter of the oil port.

[0011] Furthermore, the rotating ring can be spliced ​​by multiple arc-shaped pieces; the multiple arc-shaped pieces can be driven independently, and the multiple arc-shaped pieces drive the pressure rods connected to them to rotate; one arc-shaped piece drives the pressure rod to press multiple local protrusions in the circumferential direction.

[0012] Furthermore, the PLC control unit includes a signal processing module. The input signal of the opening and closing action of the starting module is transmitted to the signal processing module. The signal processing module determines the signal according to the high and low speed truth tables and forms an output signal. The output signal is transmitted to the main valve of the pump station motor to select high or low speed. At the same time, the output signal is transmitted to the actuator to cooperate with the pump station motor to execute the action.

[0013] Furthermore, the oil pump motor circuit of the pump station motor includes a PLC power supply, a breaker, a contactor and a thermal relay; the oil pump motor is electrically connected to the contactor through the thermal relay, and the contactor is electrically connected to the PLC power supply through the breaker; given a power signal from the coil of the PLC power supply, the motor runs after the breaker and the main contacts of the PLC power supply are energized; when the thermal relay detects that the pump station motor is overloaded, it will delay for 3S-5S; then the thermal overload signal is fed back to the programmable controller in the signal processing module, and the programmable controller outputs a signal to disconnect the pump station motor after processing, the coil of the PLC power supply loses power, and the main contacts of the PLC power supply are disconnected.

[0014] Beneficial effects: The beneficial effects of the present invention include but are not limited to the following:

[0015] 1) The oil pump motor of the column feeder is controlled by a self-locking start-stop method; the oil pump motor is controlled for thermal overload protection, and the operation of the oil pump is realized by inputting an external oil pump start button. When the pressure reaches the set pressure, the hydraulic system can enter the working state.

[0016] 2) For the motion control of the column machine, the solenoid valve combination is electrically controlled according to the design motion requirements of the hydraulic system, so as to extend and retract the cylinder to meet the control requirements of each motion;

[0017] 3) According to the requirements of the column machine control, high-speed control and low-speed control need to be realized, and the high-speed and low-speed solenoid valve switching control is realized by switching between high-speed gear and low-speed gear;

[0018] 4) The column feeder system analyzes the action requirements of the solenoid valves required for each action function according to the control requirements of the hydraulic system, and realizes the action of the column feeder by connecting the corresponding solenoid valve combination. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Attached Figure 1 It is the control system step diagram;

[0020] Attached Figure 2 This is the schematic diagram of the PLC control unit;

[0021] Attached Figure 3 This is the schematic diagram of the oil pump motor;

[0022] Attached Figure 4 This is the structural diagram of the regulating valve. DETAILED DESCRIPTION

[0023] The present invention will be further described below in conjunction with the accompanying drawings.

[0024] As attached Figure 1-4:A PLC-based electrical control system for a material column changing machine, including a starting module, a PLC control unit and a hydraulic system; by controlling the opening and closing of the starting module, the PLC control unit collects the opening and closing signals of the starting module, and transmits them to the pump station motor of the hydraulic system through the output signal of the PLC control unit, and the pump station motor selects the high and low speed states according to the output signal, and drives the actuator of the hydraulic system to perform the action; the power on and off control of multiple solenoid valve combinations can be realized according to the high and low speed hydraulic truth tables set in the PLC control unit, thereby realizing the action control of the pump station motor and the actuator. The material column machine mainly controls various actions through the power on and off of the solenoid valve. The main actions of the material column machine realized by the system include the rising and falling actions of the main hook, the rising and falling of the big arm, the rotation and telescopic actions, the rotation of the small arm, the rising and falling actions of the auxiliary arm, the forward and backward actions of the crawler, the extension and retraction actions of the legs, and the control actions of the counterweight, etc.;

[0025] For the action of the oil cylinder, the reversing solenoid valve is used to realize the forward and reverse conduction of the oil circuit. When oil is input into the rod chamber, the oil cylinder retracts; when oil is input into the rodless chamber, the oil cylinder extends. For the extension and retraction of the oil cylinder, various actions can be controlled. The hydraulic system of the column machine mainly includes hydraulic components such as the oil tank, hydraulic pump, solenoid reversing valve, pressure gauge, regulating valve and oil cylinder. The pressure gauge mainly displays the current oil pressure value. The regulating valve can adjust the speed and pressure of the extension and retraction of the oil cylinder; the regulating valve is provided with a valve, which can completely close the oil port, thereby controlling the in and out of the oil. The oil tank mainly stores hydraulic oil, and the oil pump sends the hydraulic oil from the oil tank to different oil cylinders. The function of the electromagnetic reversing valve is to realize the control of the action. The electromagnetic reversing valve generally has two electromagnetic coils, which realize the left and right movement of the valve core respectively; when the valve core moves to the left, the rod chamber extends; when the valve core moves to the right, the rod chamber retracts.

[0026] A convex ring 1 is fixedly provided on the inner wall of the oil passage port in an annular direction; an annular groove 2 is opened on the inner wall of the convex ring 1 in an annular direction, and a plurality of adjusting plates 3 are arranged in an annular groove 2; one end of the bottom of the adjusting plate 3 is hinged to the bottom of the annular groove 2, and is hinged by a movable rod 7, and an elastic member 4 is sandwiched between the other end of the bottom of the adjusting plate 3 and the bottom of the annular groove 2; one end of the adjusting plate 3 corresponds to a protrusion 5 of the elastic member 4, and the protrusion 5 protrudes from the annular groove 2; adjacent adjusting plates 3 are staggered and partially overlapped with adjacent adjusting plates 3; V-shaped grooves 51 are formed between adjacent protrusions 5; the protrusion of the adjusting plate is in the channel of the oil passage port, which limits the amount of oil passing through the oil passage port. When the protrusion is embedded in the annular groove, the oil passing space of the oil passage port is increased, so that by adjusting the movement of the protrusion, the amount of oil passing through the oil passage port can be adjusted accordingly, so that the speed and pressure of extension and retraction of the oil cylinder can be adjusted.

[0027] The regulating valve comprises a rotating ring 6, which is slidingly arranged on one side of the convex ring 1, and a driving device on the side wall of the convex ring 1 drives the rotating ring 6 to rotate; a pressure rod 61 is fixedly arranged on the inner wall of the rotating ring 6, and the pressure rod 61 is perpendicular to the rotating ring 6, and the pressure rod 61 passes through the V-shaped groove 51; the rotating ring 6 drives the pressure rod 61 to rotate, and the pressure rod 61 moves in the direction where the elastic member 4 is located, and the pressure rod 61 presses the tilting 5 of the regulating sheet 3 and embeds it into the annular groove 2, thereby realizing the adjustment of the diameter of the oil port; the driving device drives the rotating ring to rotate, and the rotating ring drives a plurality of pressure rods to rotate, and the pressure rods move to press the tilting and embed it into the annular groove, so that the opening at the convex ring is enlarged, the oil flow increases, the oil cylinder extends faster, and the opening degree of the valve on the regulating valve is increased, thereby increasing the pressure of the oil cylinder; when the rotating ring returns to the movement, the regulating valve valve is gradually closed, the oil cylinder extends slowly, and the pressure is small; thereby, the speed and pressure of the extension and retraction of the oil cylinder can be adjusted.

[0028] The rotating ring 6 can be formed by splicing a plurality of arc-shaped pieces; the plurality of arc-shaped pieces can be driven independently, and the plurality of arc-shaped pieces drive the pressure rods 61 connected to them to rotate; one of the arc-shaped pieces drives the pressure rod 61 to press a plurality of local tiltings 5 ​​in the circumferential direction. The local tiltings can be controlled to be embedded in the annular groove, and a plurality of tilting parts in the circumferential direction can be embedded in the annular groove, so that the amount of oil flow can be adjusted, and the adjustment and control can be performed according to the needs, so as to avoid the oil cylinder extending too fast or too slow, and to avoid the pressure when the oil cylinder is extended too high or too low, thereby reducing the damage to the control equipment and the failure rate.

[0029] The high-speed and low-speed truth tables include a high-speed hydraulic truth table and a low-speed hydraulic truth table; the hydraulic system uses four solenoid valves to configure the main valve, namely 1YA, 2YA, 3YA and 4YA; 1YA and 2YA are in a low-speed state, and 3YA and 4YA are in a high-speed state; the solenoid valves of the actuators are paired with 1YA, 2YA, 3YA and 4YA, respectively, to form a high-speed hydraulic truth table and a low-speed hydraulic truth table.

[0030] High speed hydraulic truth table

[0031]

[0032] Low speed hydraulic truth table

[0033]

[0034]

[0035] Low speed hydraulic truth table

[0036]

[0037] The actuator includes an auxiliary arm, and the solenoid valves of the auxiliary arm are 5YA and 6YA; when the auxiliary arm performs an auxiliary arm ascending action at a high speed, the output signal of the PLC control unit is to connect 3YA and 5YA; when the auxiliary arm performs an auxiliary arm descending action at a high speed, the output signal of the PLC control unit is to connect 4YA and 6YA; when the auxiliary arm performs an auxiliary arm ascending action at a low speed, the output signal of the PLC control unit is to connect 1YA and 5YA; when the auxiliary arm performs an auxiliary arm descending action at a low speed, the output signal of the PLC control unit is to connect 2YA and 6YA. For other actions, the action requirements are the same, and different actions have different connected solenoid valves.

[0038] The PLC control unit includes a signal processing module. The input signal of the opening and closing action of the starting module is transmitted to the signal processing module. The signal processing module determines the signal according to the high and low speed truth tables and forms an output signal. The output signal is transmitted to the main valve of the pump station motor to select high and low speed. At the same time, the output signal is transmitted to the actuator to cooperate with the pump station motor to execute the action.

[0039] The system selects PLC as the control unit of the system, collects and inputs the external column machine control panel signal, and then controls the power output of the hydraulic pump, main valve, reversing valve and other equipment. The input signal of the system includes the external key switch, emergency stop switch, oil pump start and stop switch and various action inputs; the output part of the system includes the output of the oil pump motor and the action output of the solenoid valve.

[0040] The above scheme mainly realizes the connection and disconnection of different electromagnetic reversing valves and main valves according to the action requirements of the truth table. The system is operated and controlled by professionals through the key switch, and the emergency stop switch is used to achieve emergency protection on site; the system design performs self-locking start and stop control on the oil pump, and realizes the combined connection control of the electromagnetic valve for various actions.

[0041] The oil pump motor circuit of the pump station motor includes a PLC power supply, a breaker, a contactor and a thermal relay; the oil pump motor is electrically connected to the contactor through the thermal relay, and the contactor is electrically connected to the PLC power supply through the breaker; given a power signal to the coil of the PLC power supply, the motor runs after the breaker and the main contacts of the PLC power supply are energized; when the thermal relay detects that the pump station motor is overloaded, it will delay for 3S-5S; then the thermal overload signal is fed back to the programmable controller in the signal processing module, and the programmable controller outputs a signal to disconnect the pump station motor after processing, the coil of the PLC power supply loses power, and the main contacts of the PLC power supply are disconnected.

[0042] According to the control scheme of the material column machine, the start and stop control of the system's motor is carried out, which requires the design of the motor main circuit. For the motor main circuit, the main electrical components include DZ series 3P circuit breakers, CJX2 series contactors and thermal relays. According to the power of the motor, select a suitable circuit breaker. The setting current of the circuit breaker is more than 1.5 times the rated current of the motor. It is a 3P circuit breaker, which can realize the short-circuit protection function of the motor. According to the rated current of the motor, select a suitable contactor. The rated current of the main contact of the contactor is more than 1.2 times the rated current of the motor, and the coil voltage of the contactor is AC220V. The thermal overload protection function is realized for the motor circuit. When the motor is in overload operation, in order to protect the safety and service life of the motor, the control circuit is disconnected with a delay. For the design of the motor circuit, the power first passes through the circuit breaker. The electrical symbol of the circuit breaker is QF. The power supply of the motor is connected by the on and off of the circuit breaker. The contactor is located right after the circuit breaker. The electrical symbol of the contactor is KM. The coil receives the power signal from the PLC. When the main contact is closed, the motor will run. If the coil is de-energized, the motor will stop. The thermal overload protection function of the circuit is realized through the thermal relay.

[0043] In the self-locking control circuit of the motor, the contactor coil is turned on and off from the output signal of the programmable controller. When the programmable controller outputs the signal for the motor to run, the contactor coil will be energized. At this time, after the main contact is attracted, the motor starts to run in a self-locking manner. When the programmable controller disconnects the motor running signal, the contactor coil will lose power, the main contact will be disconnected, and the motor will stop running. The thermal overload protection function of the circuit is realized by the thermal relay. When the thermal relay detects that the motor is overloaded, it will delay for a period of time and then feed back the thermal overload signal to the programmable controller. The programmable controller disconnects the output of the motor running signal according to the ladder diagram of the self-locking circuit.

[0044] For the overall design of the control system of the column material machine and the selection of hardware, it is necessary to consider the address allocation of input and output points according to the functional signals and execution units of the system. For the control system of the column material machine, the input points mainly include buttons, sensors and other signals, and the output points include contactors, solenoid valves and signal lights. The purpose of I / O allocation for the system is to determine the function of the system and provide a reference for the later compilation of PLC wiring diagrams and ladder diagrams. For the PLC wiring diagram, it is necessary to define the function of each input point and each output point, name the electrical symbols, and design the wiring diagram according to the corresponding input point type and output point type. For the compilation of the ladder diagram, it is necessary to allocate the functions of the input variables and output variable addresses according to the I / O address allocation results to ensure that the system design is accurate and complete.

[0045] Table I / O allocation table

[0046]

[0047]

[0048] Table I / O allocation table

[0049]

[0050] According to the control scheme of the material column machine, the start and stop control of the system's motor is carried out, which requires the design of the motor main circuit. For the motor main circuit, the main electrical components include DZ series 3P circuit breakers, CJX2 series contactors and thermal relays. According to the power of the motor, select a suitable circuit breaker. The setting current of the circuit breaker is more than 1.5 times the rated current of the motor. It is a 3P circuit breaker, which can realize the short-circuit protection function of the motor. According to the rated current of the motor, select a suitable contactor. The rated current of the main contact of the contactor is more than 1.2 times the rated current of the motor, and the coil voltage of the contactor is AC220V. The thermal overload protection function is realized for the motor circuit. When the motor is in overload operation, in order to protect the safety and service life of the motor, the control circuit is disconnected with a delay. For the design of the motor circuit, the power first passes through the circuit breaker. The electrical symbol of the circuit breaker is QF. The power supply of the motor is connected by the on and off of the circuit breaker. The contactor is located right after the circuit breaker. The electrical symbol of the contactor is KM. The coil receives the power signal from the PLC. When the main contact is closed, the motor will run. If the coil is de-energized, the motor will stop. The thermal overload protection function of the circuit is realized through the thermal relay.

[0051] In the self-locking control circuit of the motor, the contactor coil is turned on and off from the output signal of the programmable controller. When the programmable controller outputs the signal for the motor to run, the contactor coil will be energized. At this time, after the main contact is attracted, the motor starts to run in a self-locking manner. When the programmable controller disconnects the motor running signal, the contactor coil will lose power, the main contact will be disconnected, and the motor will stop running. The thermal overload protection function of the circuit is realized by the thermal relay. When the thermal relay detects that the motor is overloaded, it will delay for a period of time and then feed back the thermal overload signal to the programmable controller. The programmable controller disconnects the output of the motor running signal according to the ladder diagram of the self-locking circuit.

[0052] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. A person skilled in the art may make several improvements and changes without departing from the above principles of the present invention, and these improvements and changes are also considered to be within the protection scope of the present invention.

Claims

1. A PLC-based electrical control system for a column changing machine, characterized in that: It includes a starting module, a PLC control unit and a hydraulic system; by controlling the start and close of the starting module, the PLC control unit collects the start and close signals of the starting module, and transmits the output signals of the PLC control unit to the pump station motor of the hydraulic system; the pump station motor selects the high and low speed states according to the output signals, and drives the actuator of the hydraulic system to perform actions; the power on and power off control of multiple solenoid valve combinations can be realized according to the high and low speed hydraulic truth tables set in the PLC control unit, thereby realizing the action control of the pump station motor and the actuator; The solenoid valves are configured as the main valves, which are 1YA, 2YA, 3YA and 4YA respectively; 1YA and 2YA are in a low-speed state, and 3YA and 4YA are in a high-speed state; the solenoid valves of the actuators are paired with 1YA, 2YA, 3YA and 4YA respectively, so as to form a high-speed hydraulic truth table and a low-speed hydraulic truth table; The actuator includes an auxiliary arm, and the solenoid valves of the auxiliary arm are 5YA and 6YA; when the auxiliary arm performs an auxiliary arm ascending action at a high speed, the output signal of the PLC control unit is to connect 3YA and 5YA; when the auxiliary arm performs an auxiliary arm descending action at a high speed, the output signal of the PLC control unit is to connect 4YA and 6YA; when the auxiliary arm performs an auxiliary arm ascending action at a low speed, the output signal of the PLC control unit is to connect 1YA and 5YA; when the auxiliary arm performs an auxiliary arm descending action at a low speed, the output signal of the PLC control unit is to connect 2YA and 6YA; The pump station motor is provided with an oil cylinder; the forward and reverse conduction of the oil cylinder is realized by a reversing solenoid valve; when oil is input into the rod chamber, the oil cylinder retracts; when oil is input into the rodless chamber, the oil cylinder extends; regulating valves are provided at the oil passage ports of the rodless chamber and the rod chamber, and the speed and pressure of extension and retraction of the oil cylinder are adjusted by the regulating valves; A convex ring (1) is fixedly provided on the inner wall of the oil passage port in an annular direction; an annular groove (2) is provided on the inner wall of the convex ring (1) in an annular direction, and a plurality of adjustment plates (3) are arranged in an annular groove (2); one end of the bottom of the adjustment plate (3) is hingedly arranged with the bottom of the annular groove (2), and an elastic member (4) is sandwiched between the other end of the bottom of the adjustment plate (3) and the bottom of the annular groove (2); one end of the adjustment plate (3) corresponding to the elastic member (4) is tilted (5), and the tilted (5) protrudes from the annular groove (2); adjacent adjustment plates (3) are staggered, and adjacent adjustment plates (3) partially overlap; V-shaped grooves (51) are formed between adjacent tilted (5); The regulating valve comprises a rotating ring (6), the rotating ring (6) being slidably arranged on one side of the convex ring (1), and a driving device on the side wall of the convex ring (1) driving the rotating ring (6) to rotate; a pressure rod (61) is fixedly arranged on the inner wall of the rotating ring (6), the pressure rod (61) being perpendicular to the rotating ring (6), and the pressure rod (61) passing through the V-shaped groove (51); the rotating ring (6) drives the pressure rod (61) to rotate, and the pressure rod (61) moves in the direction where the elastic member (4) is located, and the pressure rod (61) presses the raised part (5) of the regulating plate (3) to be embedded in the annular groove (2), thereby realizing the adjustment of the diameter of the oil-passing port; The driving device drives the rotating ring (6) to rotate, and the rotating ring (6) drives a plurality of pressure rods (61) to rotate. The pressure rods (61) move to press and tilt and are embedded in the ring groove (2). The opening at the convex ring (1) is enlarged, the amount of oil passing is increased, the oil cylinder extends faster, and the opening degree of the valve on the regulating valve is increased, thereby increasing the pressure of the oil cylinder; when the rotating ring moves back, the regulating valve is gradually closed, the oil cylinder extends slowly, and the pressure is small; thereby, the speed and pressure of the extension and retraction of the oil cylinder can be adjusted.

2. According to claim 1, a PLC-based electrical control system for a material changing column machine is characterized in that: The rotating ring (6) is formed by splicing a plurality of arc-shaped pieces; the plurality of arc-shaped pieces can be driven independently, and the plurality of arc-shaped pieces drive the pressure rods (61) connected to them to rotate; and one of the arc-shaped pieces drives the pressure rod (61) to press a plurality of local protrusions (5) in the circumferential direction.

3. According to claim 2, a PLC-based electrical control system for a material changing column machine is characterized in that: The PLC control unit includes a signal processing module. The input signal of the opening and closing action of the starting module is transmitted to the signal processing module. The signal processing module determines the signal according to the high and low speed truth tables and forms an output signal. The output signal is transmitted to the main valve of the pump station motor to select high and low speed. At the same time, the output signal is transmitted to the actuator to cooperate with the pump station motor to execute the action.

4. According to claim 3, a PLC-based electrical control system for a material changing column machine is characterized in that: The oil pump motor circuit of the pump station motor includes a PLC power supply, a circuit breaker, a contactor and a thermal relay; the oil pump motor is electrically connected to the contactor through the thermal relay, and the contactor is electrically connected to the PLC power supply through the circuit breaker; given a power signal to the coil of the PLC power supply, the circuit breaker and the main contacts of the PLC power supply are energized, and the motor runs; when the thermal relay detects that the pump station motor is overloaded, it will delay for 3s-5s; then the thermal overload signal is fed back to the programmable controller in the signal processing module, and the programmable controller outputs a signal to disconnect the operation of the pump station motor after processing, the coil of the PLC power supply loses power, and the main contacts of the PLC power supply are disconnected.

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