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Rate (Derivative)
This parameter is adjustable from 0.0 to 10.0 minutes and specifies how the control action
responds to the rate of change in the process variable. For example, if the process variable is
rising rapidly to setpoint, power is turned off sooner than it would be if the rise were slow. In
effect, derivative action anticipates lags within the system and shifts the proportioning band by
an amount determined by the rate of change of the input sensor. Magnitude of the shift is
determined by a derivative time constant. If the time constant is, say, .1 minute (6 seconds),
for every unit per second rate of change of the process variable at the sensor, the proportion-
ing band is moved 7 units in the direction that helps control. Likewise, if the time constant is 1
minute (60 seconds), for every unit per second rate of change of the process variable at the
sensor, the proportioning band is moved 60 units in the direction that helps control. Instruc-
tions for determining rate is given in Section 4.3 (page 44). Factory is 0.0. Display code
rAtE.
Rate of Change (EO Software Option)
This parameter is used to provide ramp changes based upon a selectable rate of change.
Degrees per hours, minutes, seconds.
Second Output Position
This parameter is adjustable from -1000 to 1000 units and represents a shift or offset of the
on-off actuation points or proportional band for the second output relative to the normal
position. A positive value creates a gap where no control outputs are on, a negative value
creates an overlap of control outputs (if the first output position is at the normal position).
Second Output Position also shifts the proportional band with respect to the process value
range outside of which integral action is highlighted (reset-windup inhibit). Factory default is
0. Display code Sprd.
Segment
A segment refers to a part of a profile. A segment consists of a Ramp and a Soak section.
Setpoint Re-Transmission Output (EO Software Option)
Allows for re-transmission of the setpoint value. Factory default is 0 = not selected. Display
code Pout. If selected, must be assigned to a current output and scaled using Process/
Setpoint upper and lower values.
Soak
A Soak is the section of a profile segment where the setpoint value is at a constant value for
the time period selected.