Rockwell Automation 1771-QDC, D17716.5.86(Passport) PLASTIC MOLDING MODULE - Manual (Page 192)

Span Your Valves
Chapter 9
9-35
6. If the observed pressure HPS16 for pack and HPS33 for hold are still
not within 20% of setpoints HPC16 and HPC33, your pressure valve
is not linear over the desired range. Correct by adjusting the selected
pressure valve, output for minimum PKC43 and HDC43 as follows:
If actuals are at least 20%: And Your Selected
Valve is:
Then change PKC43, HDC43
(N44:159, N44:219) as follows
Less than setpoints Direct Acting Increase in 5% steps
Reverse Acting Decrease in 5% steps
Greater than setpoints Direct Acting Decrease in 5% steps
Reverse Acting Increase in 5% steps
To do this: change PKC43 and HDC43, download PKC, HDC, and
HPC, and repeat steps 3 and 4. Repeat as needed.
Important: If downloading from your programming terminal, download
PKC, HDC, and HPC in that order with bits B21/9, 10, and 11 (chapter 4).
What You Have Accomplished
The open-loop tuning procedure you just completed has defined the:
range of ram (screw) backpressure during plastication
end-of-range maximum and minimum signal levels for linear control of
the plastication 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 PKC41 or HDC41 PKC43 or HDC43
Maximum PKC42 or HDC42 PKC44 or HDC44
Now for all open-loop pack or hold pressure profiles, the QDC module
assumes a linear relationship between ram pressure and signal outputs.
Set Profile Pressure Alarms
Set profile maximum pressure alarm setpoints PKC57 (N44:173) for pack
and HDC57 (N44:233) for hold to a ram (screw) pressure that should:
not be exceeded during either profile
not be greater than maximum pressure control limits PKC42, HDC42
Entering a value of zero disables these alarms.
Download new values to QDC module by downloading PKC, HDC, HDC.
Important: If downloading from your programming terminal, download
PKC, HDC, and HPC in that order with bits B21/9, 10, and 11 (chapter 4).