Rockwell Automation 1771-QDC, D17716.5.86(Passport) PLASTIC MOLDING MODULE - Manual (Page 219)

Tune Your Machine
Chapter 10
10-11
Important: The injection velocity profile requires one additional velocity
setpoint beyond the last non-zero end-of position setpoint, so you must
program one more velocity setpoint than position setpoint, such that
total velocity setpoints = total position setpoints + 1
If not, the ram (screw) stops at the final end-of-position setpoint (if it does
not see a pressure transition beforehand).
Pressure Setpoints
You may use pressure setpoints in all phases of the inject mode:
For injection, use pressure setpoints to fill the mold cavity. Make them:
high enough to give sufficient pressure to fill the mold
low enough to avoid flashing the mold
For pack and hold, use pressure setpoints to relax the pressure applied to
the molten plastic as it cools in the mold.
For plastication, use backpressure setpoints to control heating the plastic
due to shearing as the rotating ram (screw) backs up the length of the
shot against a backpressure determined by your setpoints.
Important: The injection and plastication pressure profiles require one
additional pressure setpoint beyond the last non-zero end-of position
setpoint (or last non-zero segment time setpoint), so you must program one
more pressure setpoint than position (or time) setpoint, such that
total pressure setpoints = total position (or time) setpoints + 1
If not,
for the injection pressure profile, the ram (screw) stops at the final
end-of-position (or time) setpoint, unless it sees a transition before:
reaching the last end-of position setpoint
the final time setpoint has expired
for the plastication pressure profile, the final backpressure becomes
zero unless the ram (screw) reaches 100% shot size before:
reaching the final end-of-segment position
the final time setpoint has expired