Rockwell Automation 1398-PDM-xxx IQ Master Version 3.2.4 for IA-2000 and IQ-5000 Positioning Drive Modules, IQ-55 - Manual (Page 82)

60 Run Menu • Tune
Publication 1398-PM601A-EN-P — October 2000
MENUS
11. Turn off the FILTER by clearing the FILTER check box.
12. Choose the Enable button to enable the ULTRA Plus or IQ, then choose the Start button to begin
the Manual Tune process. The motor shaft will oscillate back and forth. If the Step Velocity and/or
Cycle Period need to be changed, choose the Stop button, adjust the values as necessary, and
choose the Start button again.
13. Set IGAIN to a low value (no noticeable overshoot). Set the Programmable Monitor output to
Motor Velocity (VEL1). While watching the VEL1 signal on the Monitor output with the oscillo-
scope, increase PGAIN until the desired rise time is reached.
14. Increase IGAIN until the acceptable limit for the amount of overshoot is reached.
15. Turn on the FILTER by selecting the FILTER check box, then reduce the FILTER value until the
overshoot begins to increase.
Some General Rules for Tuning:
To increase bandwidth, increase PGAIN. To increase stiffness, increase PGAIN or IGAIN. To reduce
overshoot, increase PGAIN or reduce IGAIN. To reduce rise time, increase PGAIN or IGAIN. To
reduce resonance, reduce the FILTER value. If the motor rattles, reduce PGAIN, IGAIN, or the FILTER
value.
Once the velocity loop has been tuned, the position loop may be tuned.
The parameters used to tune the position loop are KP, KI, IZONE, KFF, PZONE, and KPZ. KP is the
position loop proportional gain. Changing KP changes the position loop bandwidth. KI is the position
loop integral gain. The use of an integral gain in the position loop reduces the effects of friction and
allows zero error when holding position. KI is used in conjunction with the IZONE parameter. IZONE
is the area around the commanded position where the KI gain is active. KFF is the velocity feedforward
gain used in the position loop to minimize the following error when the system is moving. The PZONE
parameter sets a zone around the commanded position where the position loop proportional gain is
changed to the gain set by the KPZ parameter. Tuning using the step response allows adjustment of KP,
KI, IZONE, PZONE, and KPZ.
To Tune the Position Loop using Manual Tune
1. Select Gains/Limits from the Parameter menu and set the Following Error Limit Time and Size
parameters to the maximum allowed to avoid excess following error faults while tuning.
2. Select Tune from the Run menu, then choose the Manual Tune button.
3. Select Position Step as the Command Type.
4. Set the Direction radio button to Bidirectional, Positive, or Negative. The Direction setting deter-
mines the direction of motion during the Manual Tune process. The positive direction is defined as
clockwise rotation of the motor shaft when facing the motor shaft end.
5. Set the Step Position to the desired position change.
6. Set the Cycle Period value. Do not set the Cycle Period to a high value (one that would allow the
system to reach the end of travel) or to a value less than 0.02 seconds. The Cycle Period is the time
in seconds to complete one cycle of the command. If the Direction is set to Bidirectional, one cycle
is a move forward and back. If the Direction is either Positive or Negative, one cycle is the move in
one direction only.
7. Set the ILIMIT value. ILIMIT is the current limit used during Manual Tune. It is set equal to the
ILIMIT parameter when Manual Tune mode is first entered. ILIMIT can be changed here without
changing the ILIMIT parameter.
8. Set the KFF and KI parameters to 0.
9. Choose the Enable button to enable the ULTRA Plus or IQ, then choose the Start button to begin
the Manual Tune process. The motor will move back and forth. If the motor response is sluggish,
slightly increase the value of KP. If the motor response is too stiff, enter a slightly lower KP value.
10. While watching the VEL1 signal on the Monitor output with the oscilloscope, adjust KP for the
quickest response with minimum overshoot. It may be helpful to connect an LED and 2.2k ohm
resistor in series to the In-Position output to check the In-Position output during the tuning process.