8
Series 71 – Modulating Controller - Electric Actuator
Installation, Operation and Maintenance Manual
Output Signal Type - Configurable
Output signals report the position of the valve under control based on the
magnitude of the signal The minimum value corresponds to the closed
position and the maximum value to the open position Only one output
signal can be active at a time
Output Setting Description
-mA (default) Analog Current Range
Minimum mA
Maximum mA
-V Analog Voltage Range
Minimum V
Maximum V
-V Analog Voltage Range
Minimum V
Maximum V
Figure S Servo Input Settings
Failure Position Last
The Failure Position determines how the S Servo positions the valve
upon loss of input signal Loss of input signal occurs when the input signal
received is outside the valid range of the selected Input Signal Type eg
an input signal of less than mA for the -mA input The S Servo will
position the valve at the last valid commanded position before loss of signal
Dead Band Control
Dead Band Control determines the acceptable offset between the position
command provided by the input command and the current position
of the actuator determined from the feedback signal provided by the
potentiometer This value is a percentage of the full input range and creates
an inactive area centered around the desired set point For example for
a -V input command the Dead Band setting allows the actuator
position to be offset from the desired set point by up to V in either
direction creating a dead band with a span of V
Heater Setpoint
The S Servo maintains surveillance of the internal temperature of the
actuator If the internal temperature rises above F (C) the S Servo
will automatically turn off the W anti-condensation heater
Operating Modes
Remote Operation
By default the operating mode of the S Servo is remote mode where
the valve is positioned based on input signals Exiting another mode of
operation generally results in the S Servo returning to remote mode
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