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

Page 259

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Tune Your Machine

Chapter 10

10-31

When configuring end-of-profile (-stroke) set-output values, remember:

The QDC module ignores these values on all profiles (or strokes) that

are logically bridged to the next profile or movement

After the QDC module sets them, they remain in set until the QDC

module is commanded to start another movement or profile, or until the
stop command is asserted

Unselected Valve SetĆoutput Values

Refer to this title in Injection Tuning Considerations for Producing Parts.

Acceleration and Deceleration Ramp Rates

The zero ramp rates that you entered in chapter 7 disabled ramping. This
forced the QDC module to step from setpoint to setpoint during a profile.

If required by your application, you may configure your QDC module to
ramp its outputs during any profile. The QDC module uses configured
acceleration and deceleration ramp rates when moving all of its outputs
from setpoint to setpoint during any profile (figures 10.4 and 10.5).

ATTENTION: Because ramp rates are time based, using very
slow (low value) ramp rates may inhibit effective closed-loop
control, reduce ERC calculation accuracy, and limit the QDC
module’s control capability. Use ramp rates only if machine
operation mandates them.

Important: When enabled, the QDC module applies ramp rates at the
beginning of each profile segment.

With caution, you can use ramp rates to smooth jerky motion resulting
from large changes in clamp pressure or flow.

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