Watlow Series 998 - Manual (Page 113)

Misc. Features
WATLOW Series 998 User’s Manual 8.3 Applications, Chapter 8
Dead Band
The dead band prompts, [db`A] and [db`b], determine the amount of
interaction between heat (reverse acting) and cool (direct acting) control
outputs for channel A and B respectively. Dead band directly offsets the
cool control output set point. With a positive dead band, both control out-
puts will never be on at the same time. With the process in the dead
band, while it is a positive dead band, the output value is determined by
adding the output value from each control output and applying the result
to the appropriate output. If the dead band value is negative the heat and
cool outputs can be on at the same time.
Transmitter Power Supply
When option “T” is ordered for output 3 or 4, the Series 998 can supply
power to external signal conditioners, transducers or transmitters. Via
internal DIP switches, user selectable options include 5, 12 or 20VÎ (dc)
@ 30mA ratings, which are UL listed.