Watlow CPC400 - Manual (Page 104)

Chapter 4: Tuning and Control CPC400 Series User’s Guide
90 Watlow Anafaze Doc. 0600-2900-2000
Also, use the filter to reduce the process output swings and
output noise when a large derivative is necessary, or to
make badly tuned PID loops and poorly designed processes
behave properly.
Reverse and Direct Action
With reverse action an increase in the process variable
causes a decrease in the output. Conversely, with direct ac-
tion an increase in the process variable causes an increase
in the output. Heating applications normally use reverse
action and cooling applications usually use direct action.