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

Page 189

Span Your Valves

Chapter 9

9-32

Span Your Pack and Hold Pressure Valves

Span your pack valve for smooth operation at the highest desired pressure.
Do this in the following procedure by finding optimum values for words:

Title of Word

Pack Word (Address) Hold Word (Address)

Minimum Pressure Control Limit

PKC41 (N44:157)

HDC41 (N44:217)

Maximum Pressure Control Limit

PKC42 (N44:158)

HDC42 (N44:218)

Selected Pressure Valve, Output for Minimum

PKC43 (N44:159)

HDC43 (N44:219)

Selected Pressure Valve, Output for Maximum

PKC44 (N44:160)

HDC44 (N44:220)

Important: If using the same valve for pack and hold with similar values
in PKC and HDC, span this valve for pack and hold at the same time.
When you enable the pack profile, the QDC module automatically runs the
pack and hold profiles in succession. If using different valves for pack and
hold or substantially different hydraulic circuit during the profiles, span the
pack valve first. Then repeat the procedure for the hold valve.

Important: If PanelView is available for pack and hold profiles, use it to:

observe actuals
change and download setpoints
run profiles

Important: We suggest that you read this procedure before starting.

Manually jog your ram (screw) to the mold-end position so you can
exert maximum pressure against the nozzle tip.

Align all other machine hydraulics to simulate pack and hold:
enable pumps and align valves to their normal state for pack or hold.

Copy initial values PKC09-12 (N44:125-128) into DYC09-12
(N40:121-124) of your PLC-5 data table with this exception:

Important: Enter a value corresponding to zero pressure into the word
DYC09-12 (N40:121-124) for output 1, 2, 3, or 4 that drives the selected
ram (screw) pressure valve.

ATTENTION: A value of 0 does not always correspond to zero
pressure or flow. For example, a bi-directional valve requires a
set-output value of 50% (5000) to obtain 0 PSI. Valve spools or
amplifier electronics may allow pressure or flow at 0 volts.