
Span Your Valves
Chapter 9
9-22
3.
While observing actual pressure in SYS26 (N40:178) and the output
in SYS41-44 (N40:193-196) that corresponds to the selected
plastication valve, run a plastication backpressure vs. position profile.
Do this by toggling DYC04-B08 (B34/408) from 0 to 1 to 0.
4.
With your programming terminal, record:
maximum profile backpressure displayed in SYS26 (N40:178)
Record here a) ___________
%-output signal in SYS41-44 (N40:193-196) corresponding to the
ram (screw) plastication valve
Record here b)___________
5.
Compute the signal level required for the Selected Pressure Valve,
Output for Maximum PLC44 as follows:
PLC44 =
Max desired
backpressure
Observed %signal output in SYS4144 that
corresponds to the ram plastication valve
x
Observed Pressure in SYS26
Important: If your valve is reverse acting, apply the algebraic sign (–) of
value b correctly when computing PLC44 in the equation above.
PLC44 = _______________ For example, 1000 for 10%
6.
Enter new values into the PLC data table:
- value from step 5 into PLC44 (N44:400)
- max desired backpressure PPC10 from step 5 into PLC42 (N44:398)
7.
Download the PLC and PPC blocks to the QDC module.
Important: If downloading from your programming terminal, you must
download PLC first, followed by PPC (chapter 4).
To download
Set
PLC
B21/13
PPC
B21/14
8.
Run an open-loop backpressure vs. position profile. Do this by
toggling DYC02-B08 (B34/408) from 0 to 1 to 0.
9.
Observe and record actual backpressures reported by the QDC
module for all profile segments in PPS10, 14, 18, 22, 26, 30, 34 etc.
(N44:714, 718, 722, 726, 730, 734, 738, 742, 746, 750, 754).