A practical absolute position control method for multi-station center turret

Abstract

The present invention discloses a practical multi-station center turret absolute position control method, including: a center turret injection molding machine, an injection molding machine host computer, a controller, a servo driver and a servo motor; the center turret injection molding machine is connected to the injection molding machine host computer control; the injection molding machine host computer is connected to the controller IO control point; the controller is provided with a MODBUS communication module; the MODBUS communication module is used for the communication between the injection molding machine host computer and the controller; the controller is connected to the servo driver pulse control; the controller is provided with an RS‑485 communication module; the RS‑485 communication module is used for the communication between the controller and the servo driver; the servo driver is connected to the servo motor through an encoder cable and a servo motor power cable; the servo motor is arranged at the inner port of the center turret injection molding machine. Through the above method, the present invention can conveniently read the absolute position of the servo motor; improve the control repetitive accuracy; and can correct the deviation to ensure the stability of the control accuracy.

Description

Technical Field

[0001] The present invention relates to an improvement of a multi-station center turret absolute position control method, and in particular to a practical multi-station center turret absolute position control method which can conveniently read the absolute position of a servo motor, improve the control repetition accuracy, and correct the deviation to ensure the stability of the control accuracy. Background Art

[0002] The multi-station center turret is an actuator that provides the core station rotation for the injection molding machine. The multi-station center turret structure provides great convenience for single-color or multi-color handle injection molding. Currently, the existing multi-station center turrets are mostly incremental position control, and their positioning accuracy needs to be improved.

[0003] Because the multi-station center turret rotates in a single direction at a fixed angle, the existing multi-station center turret uses incremental control, which will result in cumulative errors. The controller cannot monitor the actual position of the servo drive motor, and when deviations occur, they cannot be automatically eliminated, resulting in poor long-term positioning control accuracy. Summary of the invention

[0004] The main technical problem solved by the present invention is to provide a control method that can conveniently read the absolute position of a servo motor through RS-485 communication, and utilize the constructed absolute position system to improve the control repetition accuracy. The target value can be adjusted through the program, and the deviation can be corrected, thereby ensuring a practical multi-station center turret absolute position control method with stable control accuracy.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a practical multi-station center turret absolute position control method, comprising: a center turret injection molding machine, an injection molding machine host computer, a controller, a servo drive and a servo motor; the center turret injection molding machine is control-connected to the injection molding machine host computer; the injection molding machine host computer is connected to the controller IO control point; the controller is provided with a MODBUS communication module; the MODBUS communication module is used for communication between the injection molding machine host computer and the controller; the controller is connected to the servo drive pulse control; the controller is provided with an RS-485 communication module; the RS-485 communication module is used for communication between the controller and the servo drive; the servo drive is connected to the servo motor through an encoder cable and a servo motor power cable; the servo motor is arranged in the center turret injection molding machine.

[0006] Preferably, the RS-485 communication module is provided with an SDA (TXD+) port, an SDB (TXD-) port, a RAD (XRD+) port, a RAB (XRD-) port and an SG port; The servo driver is provided with a No. 1 LG port, a No. 2 P5 port, a No. 3 RDP port, a No. 4 SDN port, a No. 5 SDP port, a No. 6 RDN port, a No. 7 LG port and a No. 8 TER port; the SDA (TXD+) port is connected to the No. 3 RDP port, and the SDB (TXD-) port is connected to the No. 6 RDN port to form a first loop; the SDA (TXD+) port and the SDB (TXD-) port are the two ends of the first loop; a first terminal resistor is provided between the SDA (TXD+) port and the SDB (TXD-) port; the RAD (XRD+) port is connected to the No. 5 SDP port, and the RAB (XRD-) port is connected to the No. 4 SDN port to form a second loop; the RAD (XRD+) port and the RAB (XRD-) port are the two ends of the second loop; a second terminal resistor is provided between the RAD (XRD+) port and the RAB (XRD-) port; the SG port is connected to the No. 7 LG port.

[0007] Preferably, the MODBUS communication module is provided with an RDA port, an RDB port, an SDA port, an SDB port and an SG port; the injection molding machine host computer is provided with a T / R+ port, a T / R- port and a GND port; the T / R+ port is respectively connected to the RDA port and the SDA port; the T / R- port is respectively connected to the RDB port and the SDB port; the GND port is connected to the SG port; the T / R+ port, the T / R- port, the RDA port and the RDB port form a third loop; the RDA port and the RDB port are the two ends of the third loop; a third terminal resistor is provided between the RDA port and the RDB port; the T / R+ port, the T / R- port, the SDA port and the SDB port form a fourth loop; the SDA port and the SDB port are the two ends of the fourth loop; a fourth terminal resistor is provided between the SDA port and the SDB port.

[0008] Preferably, RS-485 communication is implemented between the controller and the servo driver; RS-485 communication parameters are set in the program; the servo driver sets the relevant parameter PA03 to 0002 to build a communication absolute position system, PC20 is set to 0, which is the station number of the servo driver, and PC21 is set to 0010, which is the baud rate of the servo driver and other related communication parameters; other parameters of the servo driver are set according to actual needs.

[0009] Preferably, the servo driver program reads the absolute position of the servo motor through the RS instruction, and checks whether the RS-485 communication is normal by judging the returned error code; when a communication error occurs, the error flag relay is set and the alarm output is triggered; when the communication is normal, the return value is processed and transmitted to the data address; before each station rotation is started, the program adjusts the target position by iterative accumulation. The target value will be adjusted according to the absolute position of the servo motor read to avoid the occurrence of cumulative errors, and the deviations that occur during operation can be corrected, thereby realizing the rotation control of the multi-station center turret under the absolute position system.

[0010] Preferably, the controller communicates with the injection molding machine host computer via MODBUS; the controller communicates with the injection molding machine host computer in slave mode; the injection molding machine host computer quickly reads the state of the controller and other related parameters via MUDBUS communication.

[0011] Preferably, the data address is used to save the absolute position of the servo motor.

[0012] Preferably, the RS-485 communication is an RS-485 communication module.

[0013] The beneficial effects of the present invention are as follows: a practical multi-station center turret absolute position control method described in the present invention can conveniently read the absolute position of the servo motor through RS-485 communication, and utilizes the constructed absolute position system to improve the control repetitive accuracy. The target value can be adjusted through the program, and the deviation can be corrected, thereby ensuring the stability of the control accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The technical solution of the present invention is further described below in conjunction with the accompanying drawings:

[0015] Attached Figure 1 It is a structural schematic diagram of the practical multi-station central turret absolute position control method described in the present invention.

[0016] Attached Figure 2 This is a communication wiring diagram between the controller and the servo driver described in the present invention.

[0017] Attached Figure 3 Schematic diagram of the controller RS-485 communication parameter setting program of the present invention.

[0018] Attached Figure 4 It is a schematic diagram of the controller RS-485 communication processing program described in the present invention.

[0019] Attached Figure 5 It is a schematic diagram of the controller absolute position overflow prevention processing program described in the present invention.

[0020] Attached Figure 6 This is a MODBUS communication wiring diagram between the controller and the host computer described in the present invention.

[0021] Attached Figure 7 A schematic diagram of the controller MODBUS slave communication settings of the present invention. DETAILED DESCRIPTION

[0022] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0023] See also Figures 1 to 7 , the present invention comprises:

[0024] To solve the above technical problems, a technical solution adopted by the present invention is a practical multi-station center turret absolute position control method, including: a center turret injection molding machine, an injection molding machine host computer, a controller, a servo drive and a servo motor; the center turret injection molding machine is control-connected to the injection molding machine host computer; the injection molding machine host computer is connected to the controller IO control point; the controller is provided with a MODBUS communication module; the MODBUS communication module is used for communication between the injection molding machine host computer and the controller; the controller is connected to the servo drive pulse control; the controller is provided with an RS-485 communication module; the RS-485 communication module is used for communication between the controller and the servo drive; the servo drive is connected to the servo motor via an encoder cable and a servo motor power cable; the servo motor is arranged in the center turret injection molding machine.

[0025] The RS-485 communication module is provided with an SDA (TXD+) port, an SDB (TXD-) port, a RAD (XRD+) port, a RAB (XRD-) port and an SG port; The servo driver is provided with a No. 1 LG port, a No. 2 P5 port, a No. 3 RDP port, a No. 4 SDN port, a No. 5 SDP port, a No. 6 RDN port, a No. 7 LG port and a No. 8 TER port; the SDA (TXD+) port is connected to the No. 3 RDP port, and the SDB (TXD-) port is connected to the No. 6 RDN port to form a first loop; the SDA (TXD+) port and the SDB (TXD-) port are the two ends of the first loop; a first terminal resistor is provided between the SDA (TXD+) port and the SDB (TXD-) port; the RAD (XRD+) port is connected to the No. 5 SDP port, and the RAB (XRD-) port is connected to the No. 4 SDN port to form a second loop; the RAD (XRD+) port and the RAB (XRD-) port are the two ends of the second loop; a second terminal resistor is provided between the RAD (XRD+) port and the RAB (XRD-) port; the SG port is connected to the No. 7 LG port.

[0026] The MODBUS communication module is provided with an RDA port, an RDB port, an SDA port, an SDB port and an SG port; the injection molding machine host computer is provided with a T / R+ port, a T / R- port and a GND port; the T / R+ port is connected to the RDA port and the SDA port respectively; the T / R- port is connected to the RDB port and the SDB port respectively; the GND port is connected to the SG port; the T / R+ port, the T / R- port, the RDA port and the RDB port form a third loop; the RDA port and the RDB port are the two ends of the third loop; a third terminal resistor is provided between the RDA port and the RDB port; the T / R+ port, the T / R- port, the SDA port and the SDB port form a fourth loop; the SDA port and the SDB port are the two ends of the fourth loop; a fourth terminal resistor is provided between the SDA port and the SDB port.

[0027] RS-485 communication is realized between the controller and the servo driver; RS-485 communication parameters are set in the program; the servo driver sets the relevant parameter PA03 to 0002 to build a communication absolute position system, PC20 is set to 0, which is the station number of the servo driver, and PC21 is set to 0010, which is the baud rate and other related communication parameters of the servo driver; other parameters of the servo driver are set according to actual needs.

[0028] The servo driver program reads the absolute position of the servo motor through the RS instruction, and checks whether the RS-485 communication is normal by judging the returned error code; when a communication error occurs, the error flag relay is set and the alarm output is triggered; when the communication is normal, the return value is processed and transmitted to the data address; before each station rotation is started, the program adjusts the target position by iterative accumulation. The target value will be adjusted according to the absolute position of the servo motor read to avoid the occurrence of cumulative errors, and the deviations that occur during operation can be corrected, thereby realizing the rotation control of the multi-station center turret under the absolute position system.

[0029] The controller communicates with the injection molding machine host computer through MODBUS; the controller communicates with the injection molding machine host computer in slave mode; the injection molding machine host computer quickly reads the state of the controller and other related parameters through MUDBUS communication.

[0030] The data address is used to store the absolute position of the servo motor.

[0031] The RS-485 communication is an RS-485 communication module.

[0032] The controller is a Mitsubishi programmable controller FX3U-16MT; the RS-485 communication module is a Mitsubishi communication module FX3U-485-BD; the MUDBUS communication module is a Mitsubishi communication module FX3U-485ADP-MB; the servo driver is a Mitsubishi servo driver MR-J4-200A; and the servo motor is a motor that is compatible with the Mitsubishi servo driver MR-J4-200A.

[0033] The first terminal resistor, the second terminal resistor, the third terminal resistor and the fourth terminal resistor are all 330Ω.

[0034] Because the absolute position system may overflow, an overflow prevention upper limit is set in the program. Through program judgment, the current position is reset to zero before the absolute position reaches the overflow upper limit, so as to realize long-term operation of the absolute position system. The multi-station center turret rotates in a single direction at a fixed angle. When using absolute position control, absolute position overflow may occur. Therefore, overflow prevention processing is required in the program. Before the absolute position reaches the overflow upper limit, the absolute position is reset to zero at a fixed position to meet the requirements of long-term single-direction operation of the multi-station turret.

[0035] The beneficial effects of the present invention are as follows: a practical multi-station center turret absolute position control method described in the present invention can conveniently read the absolute position of the servo motor through RS-485 communication, and utilizes the constructed absolute position system to improve the control repetitive accuracy. The target value can be adjusted through the program, and the deviation can be corrected, thereby ensuring the stability of the control accuracy.

[0036] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it. They cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A practical multi-station center turret absolute position control method, characterized in that: include: A central turret injection molding machine, an injection molding machine host computer, a controller, a servo driver and a servo motor; the central turret injection molding machine is connected to the injection molding machine host computer for control; the injection molding machine host computer is connected to the controller IO control point; the controller is provided with a MODBUS communication module; the MODBUS communication module is used for communication between the injection molding machine host computer and the controller; the controller is connected to the servo driver pulse control; the controller is provided with an RS-485 communication module; the RS-485 communication module is used for communication between the controller and the servo driver; the servo driver is connected to the servo motor through an encoder cable and a servo motor power cable; the servo motor is arranged in the central turret injection molding machine; RS-485 communication is realized between the controller and the servo driver; RS-485 communication parameters are set in the program; the servo driver sets the relevant parameter PA03 to 0002 to build a communication absolute position system, PC20 is set to 0, which is the station number of the servo driver, and PC21 is set to 0010, which is the baud rate-related communication parameter of the servo driver; other parameters of the servo driver are set according to actual needs; The servo driver program reads the absolute position of the servo motor through the RS instruction, and checks whether the RS-485 communication is normal by judging the returned error code; when a communication error occurs, the error flag relay is set and the alarm output is triggered; when the communication is normal, the return value is processed and transmitted to the data address; before each station rotation is started, the program adjusts the target position by iterative accumulation. The target value will be adjusted according to the absolute position of the servo motor read to avoid the occurrence of cumulative errors, and the deviations that occur during operation can be corrected, thereby realizing the rotation control of the multi-station center turret under the absolute position system.

2. The practical multi-station center turret absolute position control method according to claim 1 is characterized in that: The RS-485 communication module is provided with an SDA (TXD+) port, an SDB (TXD-) port, a RAD (XRD+) port, a RAB (XRD-) port and an SG port; The servo driver is provided with a No. 1 LG port, a No. 2 P5 port, a No. 3 RDP port, a No. 4 SDN port, a No. 5 SDP port, a No. 6 RDN port, a No. 7 LG port and a No. 8 TER port; the SDA (TXD+) port is connected to the No. 3 RDP port, and the SDB (TXD-) port is connected to the No. 6 RDN port to form a first loop; the SDA (TXD+) port and the SDB (TXD-) port are the two ends of the first loop; a first terminal resistor is provided between the SDA (TXD+) port and the SDB (TXD-) port; the RAD (XRD+) port is connected to the No. 5 SDP port, and the RAB (XRD-) port is connected to the No. 4 SDN port to form a second loop; the RAD (XRD+) port and the RAB (XRD-) port are the two ends of the second loop; a second terminal resistor is provided between the RAD (XRD+) port and the RAB (XRD-) port; the SG port is connected to the No. 7 LG port.

3. The practical multi-station center turret absolute position control method according to claim 1 is characterized in that: The MODBUS communication module is provided with an RDA port, an RDB port, an SDA port, an SDB port and an SG port; the injection molding machine host computer is provided with a T / R+ port, a T / R- port and a GND port; the T / R+ port is connected to the RDA port and the SDA port respectively; the T / R- port is connected to the RDB port and the SDB port respectively; the GND port is connected to the SG port; the T / R+ port, the T / R- port, the RDA port and the RDB port form a third loop; the RDA port and the RDB port are the two ends of the third loop; a third terminal resistor is provided between the RDA port and the RDB port; the T / R+ port, the T / R- port, the SDA port and the SDB port form a fourth loop; the SDA port and the SDB port are the two ends of the fourth loop; a fourth terminal resistor is provided between the SDA port and the SDB port.

4. The practical multi-station center turret absolute position control method according to claim 1 is characterized in that: The controller communicates with the injection molding machine host computer through MODBUS; the controller communicates with the injection molding machine host computer in slave mode; the injection molding machine host computer quickly reads the state of the controller and other related parameters through MUDBUS communication.

5. The practical multi-station center turret absolute position control method according to claim 4 is characterized in that: The data address is used to store the absolute position of the servo motor.

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