Watlow Series 982 - Manual (Page 120)

9.6 WATLOW Series 982 User’s Manual
Software Features, Chapter 9
Software
Dead Band
Overview
The dead band prompt, [``db], located in the PID Menu, determine the
amount of interaction between heat (reverse acting) and cool (direct acting)
control outputs. The dead band directly offsets the target set point of the
cool control output.
With a positive dead band, both control outputs will never be ON at the
same time. With the process in a positive dead band, the output value is
determined by adding the percent heat output to the percent cool output
and only applying the result to the correct output — cooling action if the
sum is negative and heating action if it is positive.
If the dead band is set to a negative value, the heat and cool outputs can
both be ON at the same time.
Requirements
The dead band feature is standard on any Series 982 controller with two
control outputs. The dead band prompt will appear if the control outputs
are configured for heat/cool or cool/heat.