Rockwell Automation 1771-QDC, D17716.5.86(Passport) PLASTIC MOLDING MODULE - Manual (Page 224)

Tune Your Machine
Chapter 10
10-16
In chapter 7, you determined the signal output percentages required to
drive the unselected valves during respective profiles. These values should
allow desired ram (screw) control. Although different part set-ups and
other process considerations may require that you modify them during a
particular profile, you should adjust them only if you are unable to obtain
desired closed-loop control by modifying profile gain constants.
Important: When attempting to achieve desired closed-loop control, do
NOT change unselected valve set-output values until after you have
adjusted the profile gain constants.
Important: Large changes to your unselected valve set-output values may
require re-spanning the selected valve for that profile. Refer to chapter 9
for valve spanning procedures.
If you believe your unselected valve set-output values are adversely
affecting your ability to obtain quality closed-loop control, consider the
following:
If your Selected
valve controls:
And you observe: Then:
Pressure Profile segment pressures
substantially greater than
setpoint
Decrease the flow available during the
profile by appropriately modifying the
setĆoutput value driving the flow valve.
Pressure Profile segment pressures
substantially less than
setpoint
Increase the flow available during the profile
by appropriately modifying the setĆoutput
value driving the flow valve.
Velocity Profile segment velocities
substantially greater than
setpoint
Decrease the pressure available during the
profile by appropriately modifying the
setĆoutput value driving the pressure valve.
Velocity Profile segment velocities
substantially less than
setpoint
Increase the flow available during the profile
by appropriately modifying the setĆoutput
value driving the pressure valve.
Logical Bridges
In chapter 8, you configured your hold and plastication profiles to stop and
set outputs for no flow or pressure at completion. If your hydraulics and/or
process require NO changes controlled by your PLC-5 processor before
continuing a molding cycle, you may configure the QDC module to
logically bridge the following profile/movement pairs as integrated
machine phases:
hold/pre-decompression (HPC03-B08 = 0)
pre-decompression/plastication (HPC03-B09 = 0)
plastication/post-decompression (PPC03-B08 = 0)
Logical Bridges and
EndĆofĆprofile
SetĆoutput Values