ABB ACS550-02 User Manual page 125

Group 40: Process PID Set 1
This group defines a process PID control operation mode for the drive. In PID control
mode, the drive compares a reference signal (setpoint) to an actual signal
(feedback), and automatically adjusts the speed of the drive to match the two
signals. The difference between the two signals is the error value.
Three groups of parameters define PID control:
• Group 40 Process PID Set 1 defines process PID Set 1. Normally, this parameter
set is used.
• Group 41 Process PID Set 2 defines process PID Set 2.
Both Group 40 and 41 have the same parameters, except for the parameter used
to select the PID set (4027).
• Group 42 External / Trimming PID defines:
– an external PID control parameters or
– trimming input parameters for speed /frequency reference.
Code Description
4001 GAIN
Defines the PID Controller's gain.
• The setting range is 0.1... 100.
• At 0.1, the PID Controller output changes one-tenth as much as the error value.
• At 100, the PID Controller output changes one hundred times as much as the error value.
Use the proportional gain and integration time values to adjust the responsiveness of the system.
• A low value for proportional gain and a high value for integral time ensures stable operation, but provides sluggish
response.
If the proportional gain value is too large or the integral time too short, the system can become unstable.
Procedure:
• Initially, set:
• 4001 = 0.0.
GAIN
• 4002
INTEGRATION TIME
• Start the system and see if it reaches the set point quickly while maintaining stable operation. If not, increase
(4001) until the actual signal (or drive speed) oscillates constantly. It may be necessary to start and stop the drive
to induce this oscillation.
• Reduce (4001) until the oscillation stops.
GAIN
• Set (4001) to 0.4 to 0.6 times the above value.
GAIN
• Decrease the
INTEGRATION TIME
necessary to start and stop the drive to induce this oscillation.
• Increase
INTEGRATION TIME
• Set
INTEGRATION TIME
• If the feedback signal contains high frequency noise, increase the value of Parameter 1303
2 until the noise is filtered from the signal.
FILTER AI
4002 INTEGRATION TIME
Defines the PID Controller's integration time.
Integration time is, by definition, is the time required to increase
the output by the error value:
• Error value is constant and 100%.
• Gain = 1.
• Integration time of 1 second denotes that a 100% change is
achieved in 1 second.
0.0 = – Disables integration (I-part of controller).
NOT SEL
0.1...600.0 = Integration time (seconds).
See 4001 for adjustment procedure.
= 20 seconds.
(4002) until the feedback signal (or drive speed) oscillates constantly. It may be
(4002) until the oscillation stops.
(4002) to 1.15 to 1.5 times the above value.
FILTER AI
A
B
D (P 4001 = 10)
C (P 4001 = 1)
A = Error
B = Error value step
C = Controller output with Gain = 1
D = Controller output with Gain = 10
123
GAIN
1 or 1306
t
P 4002
Start-Up