Rockwell Automation 1771-QDC, D17716.5.87(Passport) CLAMP AND EJECT MODE - Manual (Page 53)

Configure the QDC Module's
Inputs and Outputs
Chapter 3
3-20
Configure a Digital Filter for Position Inputs from Clamp and Ejector
You can enable an optional digital filter on position inputs. This filter is
used to reduce electrical noise from potentiometer-type position sensors or
other external noise picked up by your input circuits.
To determine if you need a digital filter, move the clamp or ejector very
slowly. With your programming terminal, look for erratic position
numbers reported for clamp and/or ejector position by examining these
words:
For this Input: In Word: Look at this ProĆSet 600 Address:
Clamp SYS27 N41:179
Ejector SYS25 N41:177
Configure the QDC Module for a Digital Input Filter as follows:
To determine the time constant (0 - 00.10 sec), start with a small value
such as 00.01. A value of zero disables the filter.
To Filter this Input: In Word: Enter a Filter Time Constant in:
Clamp MCC30 N41:26
Ejector MCC44 N41:40
ATTENTION: Increasing the value of the time constant
decreases the QDC module’s capability to respond quickly to
travel limits and/or to accurately locate programmed positions.
This could result in damaging the mold assembly with possible
personal injury. We recommend keeping time filter entries
under 00.10.
For example, with a clamp velocity of 20”/sec, a 00.01 time constant
allows 0.20” of travel before the QDC module can react to a travel limit.
Important: If you have a noisy potentiometer-type position sensor and
digital filtering slows the QDC module’s response time too much, consider
replacing the sensor with a non-contact, linear-displacement type.
Download the time constants to the QDC module using the procedures
presented earlier in this chapter.