Watlow Series 988 - Manual (Page 128)

8.12 WATLOW Series 988 User’s Manual General Software Features, Chapter 8
General Software
Input Filter
Requirements
This feature is standard on all Series 988 controllers.
Overview
In certain applications the process being measured can be unstable,
which makes it difficult to control and also makes the constantly changing
display difficult to read. The Series 988 input filter can solve these prob-
lems by smoothing out just the display or the display and the input signal.
You can set a time constant in seconds for a low-pass filter that will, if you
select a positive value, affect the display only. Select a negative value to fil-
ter the input signal itself.
NOTE:
Use this feature
with caution,
because a large
time constant could
hide system
upsets.