1、 control scheme and principle
2.1 control process
the structure of screw extruder as shown below, plastic pellets fed from the hopper after heating and plasticizing, by rotating screw extruder push to the outlet, the basis of die determine the final product shape. the typical screw speed of common single screw extruder is about 100r/min, the typical screw speed of mixing extruder with dual screw extrusion is 200r/min~500r/min, usually low speed dual screw extruder speed is 10r/min~40r/min.
figure 2-1 screw extruder structure
2.2 fr200 control schematic
use frecon fr200 series 55kw inverter to drive. the main control part adopts analog input control, external control button. frecon fr200 series inverter has the following advantages: the open-loop vector control to realize high precision, high torque, torque protection. short response time, low speed with torque automatic lifting function; the hardware and software filtering, effectively improve the reliability of the system. greatly reduce the interference of noise and avoid electromagnetic interference to other devices and result in misoperation.
2.3 control requirements
ø heating device temperature is not up to set temperature, inverter can not run;
ø must form interlock circuits by external circuits;
ø before the hydraulic pump starts, the inverter cannot start;
ø when the equipment fails, the inverter must stop running.
2.4 parameter set
function of terminal di1
running forward (fwd)
function of terminal di3
external fault input
function of terminal di4
relay 1 output function
drive is running
relay 2 output function
ao1 output function
ao2 output function