Rockwell Automation 1771-QDC, D17716.5.93(Passport) PLASTIC MOLDING MODULE - Manual (Page 147)

Load Initial Profile Setpoints
Chapter 8
8-30
Profile Offset
(PPC52)
The profile offset lets you shift the amplitude of the backpressure profile
up or down, if necessary. You record this setpoint in PSI or Bar.
We recorded zero (no offset) on Worksheet 8-D.
Cushion Size
(PPC61)
This word determines the length of molten plastic that should remain in the
barrel at the conclusion of the hold profile. The QDC uses this length in
computing the 100% shot size. Units are inches or millimeters.
We recorded zero (no cushion) on Worksheet 8-D.
Shot Size
(PPC62)
This word determines the length of molten plastic drawn during the
plastication profile. Use this value to determine segment length in
End-of-segment Positions, above. Units are inches or millimeters. The
QDC uses this length for computing the end-of-plastication position (100%
shot size).
100% shot size = shot size + cushion
= PPC62 + PPC61
Record a typical shot size for your machine on Worksheet 8-D.
The valve spanning procedures in chapter 9 require these initial cushion
and shot size values. Where required, we help you select correct final
values for your application in chapter 10. For additional information, refer
to Plastic Molding Module Reference Manual (publication 1771-6.5.88).
After you determine initial values and record them on Worksheet 8-D, you
are ready to proceed. Refer to procedures in chapter 4 if necessary.
Important: Be sure that you do not alter any setpoints, and that you enter
each and every setpoint exactly as on the worksheet.
1. Enter all worksheet values into your PLC-5 data table.
2. Download command blocks to the QDC module. We repeat the PPC
block download data.
Block Block ID Command Bit Companion
PPC 15 B21/14 none
3. Check SYS61 and SYS62 for programming errors. Correct as needed.
Enter and Download your
Worksheet Values