
Span Your Valves
Chapter 9
9-6
To do this, change INC44, download INC followed by IPC with bits
B21/7, 8, and repeat steps 3 and 4 as necessary.
What You Have Accomplished
The open-loop tuning procedure you just completed has defined the:
range of ram (screw) pressure during injection
end-of-range maximum and minimum signal levels for linear control of
the injection pressure valve in open-loop control
For this
range limit
When trying to obtain
the pressure in:
The QDC module drives the selected
pressure valve to % output signal in:
Minimum
INC41
INC43
Maximum
INC42
INC44
Now, for all open-loop injection pressure profiles, the QDC module
assumes a linear relationship between ram pressure and signal outputs.
Set Profile Pressure Alarms
For Ram (Screw) Pressure - After spanning your injection pressure valve,
set the maximum ram (screw) pressure alarm setpoint INC57 (N44:53) for
the injection profile. Set it equal to a pressure value that should not be
exceeded during the injection profile. This value should not exceed the
Maximum Pressure Control Limit, INC42 (N44:38). Entering a value of
zero disables this alarm.
For Cavity Pressure - If using a cavity pressure sensor, set the maximum
cavity pressure alarm setpoint INC58 (N44:54) for the injection profile.
Set it to a cavity pressure that should not be exceeded during the injection
profile. Entering a value of zero disables this alarm.
Download new values to the QDC module by downloading INC and IPC.
Important: If downloading from your programming terminal, you must
download INC first, followed by IPC (chapter 4).
To download:
Set:
INC
B21/7
IPC
B21/8