This manual provides users with matters needing attention in installation,
1. Control Principle of Cotton Box Part
If the pressure in the carding box is relatively stable, the cotton density will be relatively uniform,
the fluctuation of the cotton layer will be relatively reduced, and the cotton box will maintain a
stable pressure, which is beneficial to improve the sliver quality.
The cotton box control part consists of four parts: the cotton box pressure sensor, the frequency
conversion driver, the cotton box feeding motor and the controller. The system adopts intelligent
PID control to make the cotton feeding motor of the upper cotton box run smoothly and keep
the pressure relatively stable. PID belongs to closed-loop control, which feeds back the
pressure value of the cotton box collected by the pressure sensor to the PID controller and
compares it with the set standard pressure value. The PID controller carries out proportional,
integral and differential control according to the difference between the standard pressure and
the actual pressure value, thus outputting a suitable voltage value to the frequency conversion
driver to control the cotton box feeding motor to keep the pressure near the set standard
pressure. The control process is shown in the figure.
Set Value; Deviation; Target Value; PID Operation; Signal; Inverter; Motor; Implement; External
Process; Action; Sensor; Process Variable (Feedback)
2.
Control Principle of Leveling Part
The leveling control is composed of sensor, frequency conversion driver, cotton feeding motor
and controller. The sensor part includes two cotton layer thickness detection sensors at the
feeding roller, a sliver detection sensor at the exit and a doffer speed sensor.
The working principle is shown in the following figure, the controller of the leveler tracks the
speed of the doffer by approaching the switch, and detects the thickness of the input cotton
layer through two thickness displacement sensors. The sliver thickness is detected by the sliver
thickness sensor.
The QFT-031A series leveller detects the doffer speed through a proximity switch installed on
the doffer pulley. This speed is used as the basis for controlling the speed of cotton feeder motor.
When the feeding cotton layer is completely uniform, the cotton roller runs with Doffer in a fixed
proportion.
When the feed cotton layer thickness changes, the controller detects the cotton layer thickness
change signal through the thickness sensor and carries on the operation analysis and
processing, calculates the drawing compensation amount, and changes the draft ratio of the
cotton feeding roller to the doffer by changing the speed of the cotton feeding motor. So as to
ensure a constant quantitative output of sliver.
The sliver sensor detects the final sliver quality. When the controller detects that the sliver
sensor changes more than a certain value, the speed of the feeding motor will be changed
through calculation and analysis to ensure the sliver quality of the long sliver.
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