Introduction to Huceen PLC Project
This project is a 16 zone twin screw extruder, and its control unit includes a host heating system, host speed control system, traction control system, cutting control system, and some safety protection functions. The working process involves heating the screw barrel and mold, holding it for a certain period of time after reaching the set temperature, starting the main machine for extruding, and then starting the traction after discharging. The cutting length is set on the screen, and the cutting machine is started after reaching the set length.
Electrical control scheme
Temperature control: The entire equipment has 24 temperature zones, including 7 for the barrel, 15 for the mold, 1 for the melt temperature, and 1 for the confluence core temperature. The barrel part needs to have heating and cooling functions, the mold part and the confluence core temperature only need heating functions, and the melt temperature only needs to be measured at the actual temperature.
Speed control: Two analog outputs are required to control the speed of the main engine and traction machine.
Analog quantity measurement: Four analog quantities are required to measure the host current, host speed, melt pressure, and traction speed respectively.
Digital output: Control the heating, cooling, and other signal outputs of the host to start the temperature zone, with 31 channels.
Digital input: encoder input, 13 point input for each alarm signal.
Main control functions of PLC
The touch screen can monitor the operation of the entire production line, and the host and auxiliary control systems can also run separately; Can achieve closed-loop control of machine head pressure to ensure product quality; The main screw and feeding frequency converter can conveniently achieve synchronous speed regulation; The high-performance PID algorithm for temperature control adopts heating and cooling control methods (suction cooling and air cooling) in the temperature zone of the machine barrel, achieving ideal dynamic and static performance of temperature control; The main screw has a protective function, which can prevent accidental operation from damaging the main screw; Realize pipe wall thickness control and save materials; Fault alarm function, which can display the cause, location, occurrence time, and troubleshooting methods of faults, and can store 700 historical alarm records; Real time display of temperature curves, nose pressure curves, etc. in each temperature zone; Multiple extrusion production lines can be networked and centrally controlled.
As the core equipment of the plastic production line, the control system of the extruder mainly focuses on temperature control, and there are many temperature zones. Both digital quantity and temperature measurement require a system with large number of points to achieve. Huichen Automation Complete Solution, Stable and Reliable Performance! The PLC development and debugging ideas are consistent with S7-200SMART, and engineers do not need to learn again, making a perfect transition. High cost-effectiveness, improving the price ratio of customer products.