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Process Rounding
This Tune mode parameter is used to determine the step size of the process value that will be
seen on the display. This feature can be used to reduce display fluctuation. This parameter
is adjusted from 1 to 100 degrees/units. The factory default is 1,no rounding (e.g. Process
rounding = 2, Process Value Display - 4, -2, 0, 2, 4, etc.).
Process Variable
The process variable refers to the condition of the process being measured (sensed). The
instrument will accept process inputs other than temperature (pressure, level, flow, etc.).
For the Auto Tune feature to work, the process value must be temperature from a
thermocouple or an RTD.
Proportional Band
This Tune mode parameter selects the span of the proportional output range. This parameter
is adjustable from 1 to 3000 degrees/units. Factory default is 100. If Output 1 is selected as a
proportional output, a display code of Pb1 will be seen. If Output 2 is selected as a propor-
tional output, the display code will be Pb2. The Pb1 value will be automatically selected if the
Auto Tune function is used.
Rate (Derivative)
This Tune mode parameter is adjustable from 0.0 to 10.0 minutes. The value selected
represents how much sooner a PID instrument will recover from a process upset than a PI
only instrument will recover to the same process upset. If Output 1 is selected as a propor-
tional output, rt1 will be displayed. If Output 2 is selected as a proportional output then rt2 will
be displayed. The rt1 value will be automatically selected if the Auto Tune function is used.
Second Output Position
This Tune mode parameter is used to shift (deviate) the Output 2 operating point from
setpoint. This parameter is adjustable from -1000 to + 1000 degrees/units. Factory default is
0. The display code is SoP.
Setpoint Ramp Rate
This Program mode parameter provides a rate of change control of the instrument setpoint
value. This parameter is used to inhibit sudden upsets in the instrument control caused by
large setpoint changes. This feature also creates a soft start when the instrument power is
turned on. The instrument will read the process value at the time the power was turned on as
the setpoint value. A rate of change ramp will change the internal setpoint to the setpoint
selected.