The ZK-3 tension controller detects the tension of the material through a tension sensor, compares it with the set value, performs PI calculation processing, outputs excitation current to drive the magnetic powder brake, causes damping of the magnetic powder brake, controls the damping torque of the material unwinding core, and thus controls the tension of the material.
ZK-3 tension controller is an upgraded product of ZK-1 type.  

1、 Function of tension controller
1. This system uses an 8051 microcontroller as the central processing unit and applies digital design concepts. The tension calibration process is simple and there are no adjustable potentiometers such as "zero" and "full".  
2. Digital display of "real-time tension value" (PV), "tension set value" (SV), and "output quantity".  
3. It has manual and automatic control functions.  
4. The "tension setting value" can be input externally, and the interface signal is 0-20mA (or customized 0-10V).  
5. It can input "real-time tension value" externally, with an interface signal of 0-20mA (or customized 0-10V).  
6. The upper limit, lower limit, and shutdown value of the output control quantity can be set by the user.  
7. Synchronize the output of 0-20mA (or 4-20mA) tension control signals, making it convenient for users to connect with devices such as frequency converters.  
8. Adopt a step-down switching power supply with constant current output for the excitation current of the magnetic powder brake.  
9. Built in EEPROM data storage, which can permanently store user's status settings without losing data in case of power failure.  
10. Built in crash self recovery circuit and EMI interference suppression circuit, the system can work in harsh environments.  

2、 Technical specifications of ZK-3 tension controller
1. Tension control range: 0 to full range
2. Tension error: ± 2%
3. Output current: 0-3A (RL=12 ohms)
4. Power supply voltage: 220V ± 10%
5. Installation method: Embedded, width * height * depth=200 * 150 * 200;  

3、 Principle diagram

4、 Panel diagram

1. PV: Display real-time tension values.
2. SV: Use the "Monitoring Selection" button to select and display "Set Tension Value", "Percentage of Output", and "Excitation Current Value (0-3A)".
3. "Manual" and "Auto" buttons: When in the "Manual" position, adjust the output through the "Manual" knob; When in the "automatic" position, the system enters the automatic control state.
4. "Setting" knob: used to adjust the set tension value;
5. "Manual" knob: used to adjust the output in "manual mode", invalid in "automatic" position.
6. "Tracking" knob: During automatic control, change the tracking speed of the control quantity to minimize the actual tension reading swing and improve control accuracy.
7. "Upper limit", "Lower limit", and "Reserve" indicator lights: indicate the current output status (upper limit value, lower limit value, reserve value).  
5、 Synchronous control
The ZK3 tension controller has a set tension input interface (0-20mA), which can be used to form a synchronous tension control system to synchronously control the tension of materials on a production line.