Function Prompt
Selections or Range of
Setting
Parameter Definition
setpoint (SP) to determine the sign
of the error (ERROR = PV–SP). The
ON/OFF algorithm operates on the
sign of the error signal.
In Direct Acting Control, when the
error signal is positive, the output is
100 %; and when the error signal is
negative, the output is 0 %. If the
control action is reverse, the
opposite is true. An adjustable
overlap (Hysteresis Band) is
provided between the on and off
states.
ATTENTION: Other prompts
affected: OUT Hysteresis
DUPLEX ON/OFF is an extension of
this algorithm when the output is
configured for a Duplex control
algorithm. It allows the operation of
a second ON/OFF output. There is a
deadband between the operating
ranges of the two inputs and an
adjustable overlap (hysteresis) of
the on and off states of each output.
Both Deadband and Hysteresis are
separately adjustable. With no relay
action the controller will read 50 %.
ATTENTION: Other prompts
affected: OUT Hysteresis and
Deadband
PID A PID A is normally used for three-
mode control. This means that the
output can be adjusted somewhere
between 100 % and 0 %. It applies
all three control actions—
Proportional (P), Integral (I), and
95
Chapter 4 - Configuration
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