Rockwell Automation 1771-QDC, D17716.5.87(Passport) CLAMP AND EJECT MODE - Manual (Page 190)

Tune Your Machine
Chapter 10
10-17
You can configure clamp and ejector ramp rates in order to:
Smooth out jerky motion present during large increases or decreases in
clamp/ejector pressure or flow
Decelerate the clamp during a close profile prior to Low Pressure
Close. This may prevent possible mold or machinery damage or
excessive wear when your application requires moving toward the Mold
Protection Zone at relatively high velocities during the clamp close
operation.
Decelerate the clamp during an open profile prior to Open Slow. This
may enhance your full open position repeatability when your application
requires moving toward the Open Slow Zone at relatively high
velocities during the clamp open operation.
If your application requires the use of ramp rates, remember:
Ramp rates should never be applied until you have already tuned all
applicable clamp and ejector pressure and velocity loops.
Ramp rates can be applied to both selected and unselected valves.
Therefore, even though you may be controlling velocity, you can ramp
clamp pressure during a close profile prior to executing Low Pressure
Close.
Ramp rates and ERC do not always function properly together, and care
should be taken whenever utilizing both for conjunctive control.
Use of slow ramp rates may make the pressure and velocity actuals
returned to the appropriate status blocks appear to be out of control,
since the actuals reported back per profile segment include the time
spent ramping up/down from the old valve signal to the desired new
signal level.
The QDC module uses a respective profiles ramp rates upon entry into
profile execution as well as when stepping from segment to segment in
that profile. As an example, Second Clamp Close ramp rates are
utilized after completion of First Clamp Close when transitioning to the
first segment setpoint in Second Clamp Close, and when transitioning
from segment to segment within Second Clamp Close.
QDC ramp rates are entered in units of 0 to 9999% signal output per
second (note that there is no decimal point). A ramp rate entry of 9999
allows the output to move “full range” in 10 milliseconds, while a ramp
rate entry of 99 forces the QDC module to consume a full second if it is
required to “full stroke” an output.