Rockwell Automation 1771-QDC, D17716.5.93(Passport) PLASTIC MOLDING MODULE - Manual (Page 235)

Tune Your Machine
Chapter 10
10-7
Tune Velocity Loops Without An Oscilloscope
Before you begin tuning your velocity loop, confirm that you:
selected the velocity vs. position algorithm
selected closed-loop control
zeroed the VelFF term
disabled
ERC
reset ERC values
disabled
ramping
ATTENTION: Verify that you have correctly set the following
words and bits in CPC and OPC that control zone overrun to
guard against damaging the clamp or mold.
CPC03-B11 = 0: execute low pressure close if zone overrun occurs
set CPC61 to a value larger than normal for a larger mold-protect zone
OPC03-B11 = 0: execute open slow if zone overrun occurs
set OPC61 to a value smaller than normal for a larger open-slow zone
1. Enter an operational profile representative of characteristics you
desire for your production cycle.
2. Downloaded all setpoint changes to the QDC module.
3. Run several profile cycles while comparing profile actuals with
profile setpoints. Also observe hydraulic hoses leading to the
cylinder as follows:
If: Then:
Observed actuals are consistently well below
profile setpoints
Increase the proportional term
Observed actuals are consistently well above
profile setpoints
Decrease the proportional term
Excessive hammering and vibration is
observed in the cylinder's hydraulic lines
Decrease the proportional term
Important: Each time you change a gain constant, you must download the
change to the QDC module. Refer to download procedure in chapter 4.
4. Re-run the profile after each change to the proportional term until
observed actuals are close to setpoints without hammering and
vibration in hydraulic lines to the controlled cylinder.
Important: If you cannot make velocity actuals match entered setpoints,
verify that your unselected valve set-output values are correct for your
application (Refer to chapter 7 and the discussion later in this chapter).