Vacuum Furnace,High Vacuum Furnace,Vacuum Heat Treatment,High Temperature Vacuum Furnace Zhejiang Shangding Industrial Furnace Co., Ltd , https://www.sdindustrialfurnace.com
The traditional elastic wire machine adopts the DC motor speed control system, which has the disadvantages of large motor maintenance workload, complicated mechanical gear transmission structure, change of process must stop and change process gear, etc., so it is gradually replaced by a new type of variable frequency speed control system. The elastic yarn machine adopting the frequency converter speed control system drives the independent transmission of each shaft through multiple frequency converters, which not only cuts the process gears, but also simplifies the structure of the transmission system, reduces the processing and assembly workload, and improves the system reliability; It meets the requirements of reducing manufacturing costs, saving energy consumption, and adapting to small-volume, multi-variety process changes in the user market.
The transmission system of the high-speed stretch yarn machine includes a 4-speed drafting roller (upper feeding roller, middle feeding roller, lower feeding roller, winding roller), and a false twisting belt, a friction roller and a traverse roller, each requiring The transmission part is synchronously operated and the ratio is adjustable. At the same time, the tension of the wire is constant during the operation, that is, the speed of each motor driven by the inverter is stable, and the steady-state speed regulation accuracy is less than 0.1%. Therefore, two kinds of variable frequency speed control schemes are generally adopted: asynchronous Motor closed loop vector control and synchronous motor open loop control. When using the synchronous motor scheme, the system control is relatively simple, but the cost of the synchronous motor is much higher than that of the asynchronous motor; the closed-loop vector control of the asynchronous motor is adopted, because the speed feedback needs to be introduced, the system is relatively complicated, but the cost is low. In addition, the temperature control part of the high-speed elastic wire machine generally adopts the method of temperature acquisition, PID calculation by PLC, and control of the heater by pulse width modulation (PWM) output thyristor.
2. Control system scheme The control system of high-speed stretch yarn machine adopts Micro PLC as the control core. Modbus communication expansion card (TSXSCP114 is used as the main station) on the CPU module, and ATV58F or ATV58 (with VW3A58202 encoder feedback expansion card) series is adopted. The inverter (built-in Modbus interface, as a slave), realizes the control of the transmission system through the Modbus bus communication control mode; the temperature control part uses a dedicated temperature acquisition card with a Modbus bus interface (as a slave), through the same Modbus bus The temperature signal is collected into the Micro PLC, and after being calculated by the PID with the set temperature, it is output through the switch output port. At the same time, the Magelis XBT-G 10.4†black and white touch screen is configured to realize the line speed, the draw ratio and the temperature of each point. Setting and monitoring of the entire system. Due to the large amount of system programs, a 32K memory expansion card (TSXMFP032P) is also configured on the CPU module of the Micro PLC.
3. Introduction to Control System When the ATV58/58F inverter adopts the closed-loop flux vector control method with speed sensor feedback, the static speed regulation accuracy is 0.02%, which fully meets the speed regulation requirements of the high-speed elastic wire machine. In addition, ATV58F inverter has built-in incremental encoder interface, the encoder power supply voltage is +5V; using ATV58 inverter needs to configure VW3A58202 encoder feedback expansion card, the encoder voltage is +24V.
The ATV58/58F inverter has a built-in Modbus interface (ie, operation panel interface), which can be controlled by communication control method with a control accuracy of 1 revolution (equivalent to 0.015 Hz). The communication mode control of the frequency converter not only can effectively avoid the common mode interference and analog/digital conversion precision error caused by the traditional analog signal control, improve the reliability and accuracy of data transmission, and can simplify the wiring mode at the same time. And achieve two-way exchange of information.
The physical layer of Modbus interface built in ATV58/58F inverter is RS485, adopt Modbus RTU mode (8 data bits, 1 stop bit, no parity), the baud rate must be 19.2Kbit/s, and the connection medium can be shielded. Twisted pair cable with a transmission distance of up to 1000 meters and a physical layer limit of up to 18 inverters connected to a single bus. The interface (SUB-D9) RS485 pin definition and matching terminal are as shown below.
When using the built-in Modbus interface of the ATV58/58F inverter, you need to set the following in advance through the operation panel:
Control menu (CTL: 4-CONTROL)
Panel Control (LCC: Keypad Comm.) – No (Cancel Panel Operation)
Inverter address (Add: DriveAddress) -- 1,2,..., 31 (Modbus slave address)
Micro PLC programming software PL7 Pro provides a wealth of library functions (Library Funtion), such as PID, PWM adjustment instructions, etc., to provide maximum convenience for system programming.
Application of Micro PLC in high speed elastic wire machine
1. Introduction The elastic wire machine is a post-processing equipment for pre-oriented yarn (POY wire) produced by high-speed spinning. It is made into a stable performance by heating, false twisting, drawing, oiling and other processes on POY wire. A stretch yarn (DTY wire) with performance properties is packaged and packaged into a spindle that meets the process requirements for subsequent weaving.