Rockwell Automation 1771-QDC, D17716.5.87(Passport) CLAMP AND EJECT MODE User Manual

Page 169

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Span Your Clamp and Ejector Valves

Chapter 9

9-33

What You Have Accomplished
The valve spanning procedure you just completed has:

defined the range of pressure available during any ejector profile

informed the QDC module of the signal level needed to drive the

selected ejector pressure valve(s) for any requested open-loop pressure:

% of Signal Level Entered In:

Drives the Selected Valve to Produce:

EAC43 and ERC43

Pressure (usually 0) in EAC41 and ERC41

EAC44 and ERC44

Pressure in EAC42 and ERC42

Now, for all open-loop pressure-controlled ejector profiles, the QDC
module:

drives the selected ejector pressure valve between the signal limits

imposed by EAC43 and EAC44, or ERC43 and ERC44

assumes a linear relationship between ejector pressure and the signal

outputs

Set Pressure Alarm Setpoints

After spanning your Ejector pressure valve(s), set your Ejector Profile
maximum pressure alarm EAC57 equal to a value you feel should not
occur during either Ejector Advance or Ejector Retract. Make sure this
value is not greater than the Ejector Advance and Ejector Retract
Maximum Pressure Control Limits (EAC42, ERC42). Entering a value of
0 disables this alarm.

Download changes to the QDC module. If necessary, refer to the
Download Procedure in chapter 4.

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