Application of ultrasonic sensor in tension control improvement of rewinder
The tension control of the rewinder is realized by controlling the unwinding part. There are two ways to control the unwinding part of the rewinder in our company, one is magnetic particle control, the other is motor control. The magnetic powder controller control mode is based on the size of unwinding roll diameter, paper quantitative, disk diameter requirements and other process parameters, through the magnetic powder controller to adjust the tension size of the unwinding part, the control precision is poor, low degree of automatic control, and the motor control mode uses the frequency converter to drive the motor, the speed is calculated by the simulation given and the automatic measurement of the coil diameter, high stability, easy to operate, Most of our company's magnetic powder control mode of the rewinding machine has been transformed into a frequency converter control mode.
1 Rewinding machine unwinding part transformation principle
The unwinding part of the rewinding machine is changed from the magnetic powder control mode to the motor control mode. An AC asynchronous motor of the unwinding part is added on the basis of the original equipment. Driven by the Siemens 6SE70 series frequency converter, a knob potentiometer is added on the operating table as the main given, and a UC2000 series ultrasonic sensor is installed vertically on the paper roller of the unwinding part. Within the working range of the sensor, the analog signal of 0~10V can be output to compensate the change of the winding diameter in the process of unwinding. Through the function of the converter itself, the two analog input signals of the collected potentiometer and ultrasonic sensor can be calculated and acted on the unwinding motor as the given tension of the unwinding part, so as to realize the automatic adjustment of the tension of the unwinding part. Its control principle, parameter setting, specific function diagram and function block are illustrated in FIG. 1 to FIG. 3.
The operating station potentiometer is mainly connected to the converter, which simulates input channel 1, namely ALL-K0011. The function diagram is shown in the inclined wave function of the tension potentiometer input (FIG. 1). The parameters of the converter are set as follows:
U951.87 = 10
U380=K0011
U383.1 -- 60S(ACC)
U383.2-60S(DEC)
Figure 1. Input oblique wave function of tension potentiometer
The ultrasonic sensor signal line is connected to the two terminals of the analog input channel of the converter, and the output signals of the sensor diameter probe at different positions within the working range, namely AI2-K0013, are input to the converter. Here we collect ten groups of output signals at different positions and set them into the parameters of the converter. Through the function of the frequency converter itself, the collected signal is formed into a curve, namely the characteristic curve of the probe diameter (Figure 2), to depict the change of the winding diameter. The parameters of the frequency converter are set as follows:
U951.07 = 10
U190= K0013
U191.01toU191.1O is input X
U192.01toU192.10 is the output Y
Figure 2. Diameter characteristic curve of probe
The tension can be automatically adjusted in the process of winding diameter change by using the function of frequency converter. The realization of frequency converter parameters and function diagram is illustrated in Figure 3.
U951.04=1O
U107.01=K0541
U107.02=K0577
FIG. 3 Set value of unwinding tension
2. Debugging of ultrasonic sensor
The application of ultrasonic sensor plays a key role in this transformation, so its debugging is very critical, including the setting of switching function and switching point. The switching function determines the working trend of the sensor (see Figure 4), and the setting of switching point determines the working range of the ultrasonic sensor.
Figure 4 Sensor switch function
The specific process of setting the switch function is as follows:
Power off one dial set plug - restore power (reset) - Connect the set plug to E2 / E3 set working mode - Connect the set plug to position T - set completion.
There are three configurable working modes with different indicator states: Function 1: LEDA1 blinks; Function two, LEDA2 flickers; Function three, LEDA1 and A2 flicker. After setting the working mode, set the plug to the position T. The setting process is completed and the sensor works in the normal mode.
Secondly, the setting of switch points 1 and 2 should be carried out. The specific process is as follows:
Disconnect the power supply by dialing the setting plug - restore the power supply (reset) - Plug in and remove the setting plug at position 1 and position 2 - Connect the setting plug to position T - setting is complete.
During setting, remove the setting plug and the target position value is adopted. Position 1 is the position detected when the roll is empty, position 2 is the position detected when the maximum roll diameter, switch point A1 or A2 is set, also determines the sensor detection range, between the two points can be evenly distributed into ten points, forming the trend curve of roll diameter change. The setting process is indicated by the LED. If the green LED blinks, the target is detected. If the red LED blinks, the target is not detected. After the setting is completed, the setting plug is inserted into the position T. The setting process is completed and the sensor works in normal mode.
Rewinder tension control directly affects the rewinding quality of paper roll, in this transformation using UC2000 ultrasonic sensor compensation roller diameter change caused by the tension change of this method, can fully realize the automatic control of tension adjustment, in the use of several years, the failure rate is small, high stability, easy maintenance, automatic control degree is more advanced, It will be widely used in the future design transformation.
