Watlow Electric 989 Marine Instruments User Manual


 
8.22 WATLOW Series 988 User’s Manual
General Software Features, Chapter 8
General Software
Slidewire Feedback
Requirements
A slidewire configuration uses at least two inputs and two control out-
puts. Input 2 can only be selected as a slidewire input (98_ _-_3_ _-_ _ _ _).
Overview
The Series 988 can control the position of a valve with a slidewire feed-
back position indicator. The controller senses the resistance of the
slidewire and compares it to the range low and range high settings to
determine the valve position. The controller compares this to the percent
output and takes action to match the two by opening or closing the valve.
Set the hunt [hunt] parameter to limit valve hunting. The value is set for
the percent of output (0.0 to 100.0). When the valve is within this dead
band, a change in output greater than half the hunt parameter is required
to trigger action. Output 1 responds to “close” commands and output 2
responds to “open” commands.
NOTE:
Outputs must be
compatible with the
slidewire valve actu-
ators.