Rockwell Automation 1771-QDC, D17716.5.86(Passport) PLASTIC MOLDING MODULE - Manual (Page 231)

Tune Your Machine
Chapter 10
10-23
The QDC module uses a proprietary, enhanced control scheme called
Expert Response Compensation (ERC). It compensates for changes in
your machine dynamics, machine hydraulics, raw materials, and other
process variables. It also adjusts the open-loop and closed-loop control
algorithms to compensate for abrupt upsets and long term deviations to
your process. In previous chapters, you ran profiles with the QDC
module’s ERC algorithm disabled.
Use ERC:
for normal operation when strict adherence to velocity or pressure (not
position) setpoints is required.
Do NOT use ERC:
when spanning your valves
if using velocity feedforward Vel/FF gain
if using slow (low value) acceleration or deceleration ramp rates
until you have properly tuned the control loop
Jerky, abrupt ram (screw) motion may result if you apply ERC to a control
loop that has not been properly tuned.
ERC Minimum Percentage Values
If using ERC, use minimum percentage values recommended in chapter 7,
except for the following:
If ERC is enabled (on) and: Then:
The actual velocity or pressure swings wildly
around the setpoint from cycle to cycle
Decrease the ERC minimum %
The actual velocity or pressure takes several
cycles to achieve the desired setpoint
Increase the ERC minimum %
Expert Response
Compensation