High Country Tek HGC-2, Closed Loop Controller - Manual (Page 7)

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Electronic Controller Solutions for the Global Fluid Power Industry
Controller Set-up: PID Tuning
Tuning the PID loop on the HGC-2-XX:
The HGC-2-XX has a true Proportional (P), Integral (I) and Derivative (D) closed loop correction
system built into it for maximum accuracy speed control and load correction.
The ‘P’, ‘I’ and ‘D’ values (coefficients) can be adjusted from 0 to 100% in each case .
1.
Enter the Target Frequency the controller will maintain - 50 or 60Hz
2. Use Frequency Adjustment to trim O/P frequency if needed ( +/-3Hz in 0.1Hz increments )
3. Enter the Min and Max current range of the valve or pump coil into the boxes.
4. Enter the Min Frequency allowed by your application.
5. Enter the Max Frequency allowed by your application.
6. Set the dither to the valve dither required in the valve literature. 140 Hz is a good starting
point for most valves and pumps. Too much dither will cause the spool to go unstable, too
little and the response will be slow.
7. Start the tuning sequence with the ‘I’ and ‘D’ values set to zero (10)
8. Set the ‘P’ value set to an initial small number (~50).
9. To test these preliminary settings, and get a feel for the system response, changes in
demand should be triggered by changing the AC load on the generator output or the pump
speed by changing the prime mover RPM ( throttle position ) .
10. Watch the generator output frequency after each change occurs in the GUI graphing section.
11. If the frequency is oscillating around the setpoint, the ‘P’ value is too high.
12. If the frequency is not achieving the setpoint (over or under) the ‘P’ value may be too low.
13. Adjust the ‘P’ value up until oscillation starts to occur, then reduce it just enough to stop the
oscillation.
14. Remember to repeat step 3. After any changes in the ‘P’ setting to ensure stability. Ensure
changes are made over the whole oil temperature range expected to be seen in the
application as viscosity can affect system stability at this early stage.
15. At this point, the generator frequency will potentially not always achieve the Target frequency
setpoint after every change in AC load on the generator output or pump speed is made as
the controller is only using the ‘P’ setting – this is normal.
16. Now, introduce changes again and start to increase the ‘I’ setting just enough to allow the
frequency to achieve the Target frequency setpoint after every change to the AC load on the
generator output or the pump speed.
17. If the ‘I’ setting is too high, oscillations will occur.
18. If the I setting is to low, the target frequency will not be reached as in 9.
19. Once the generator is stable and responding well to changes in generator load or pump
speed, the ‘D’ setting can be increased to allow the closed loop controller to limit the
generator output frequency over and undershoot during AC load or pump speed changes.
20. If the ‘D’ setting is too high, oscillations can start to occur.
21. Once the ‘D’ setting has been made, the user should once again apply as many load and
speed changes as possible to simulate the applications intended operating situations.
22. If the frequency oscillates or is not stable, the procedure above may need to be repeated to
‘fine-tune’ the system.
End of PID tuning section.