Rockwell Automation 1771-QDC, D17716.5.93(Passport) PLASTIC MOLDING MODULE - Manual (Page 250)

Tune Your Machine
Chapter 10
10-22
Expert Response Compensation
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 acceleration or deceleration ramp rates
until you have properly tuned the control loop
ATTENTION: 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, adjust values recommended in chapter 7 as follows:
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 % value
The actual velocity or pressure takes several
cycles to achieve the desired setpoint
Increase the ERC minimum % value