Once the ramping setpoint reaches the target setpoint, the setpoint ramp rate disengages until the setpoint is changed again. If the ramp value is changed during ramping, the new ramp rate takes effect. If the setpoint is ramping prior to invoking Auto-Tune, the ramping is suspended during
Auto-Tune and then resumed afterward using the current display as a starting value. Deviation and band alarms are relative to the target setpoint, not the ramping setpoint.
The Remote Setpoint input is also controlled by the setpoint ramp feature.
In situations where the remote setpoint must be rate controlled, this parameter can be used to slowly increment (or decrement) the signal to its final value.
The target value, not the instantaneous ramp value, is displayed. Setpoint ramp indication is disabled during remote setpoint ramping.
Note: Depending on the ramp rate relative to the process dynamics, the actual scaled process value may not track the ramping setpoint value.
User Input (InPt)
The user input may be programmed to perform a variety of controller functions. The input must be in its active state for 120 msec minimum to perform the function. A function is performed when the User Input,
(Terminal 6) is pulled low to common (Terminal 8).
Note: Do not tie the commons of multiple units to a single switch. Use either a multiple pole switch for ganged operation or a single switch for each unit.
Note: “Low Level” is switch closed.
“High Level” is switch open.
PLOC - Program Lock. A low level enables the program disable function which places the unit in the Protected Parameter Mode.
ILOC - Integral Action Lock. A low level disables the integral action of the
PID computation. A high level resumes the integral action.
trnF - Auto/Manual Transfer. A negative transition places the unit in the manual (user) mode and a positive transition places the unit in the automatic operating mode. The output is “bumpless” when transferring to either operating mode.
SPrP - Setpoint Ramp. A low level terminates setpoint ramping and the controller operates at the target setpoint. Terminating setpoint ramping is the same as setting the ramp rate to zero (SPrP = 0.0). A high level enables the programmed setpoint ramp rate.
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ALrS - Alarm Reset. On models with alarms, a low level resets any active alarm(s) to their inactive state as long as the user input is low.
SP2 - Setpoint 1/ Setpoint 2 Select. On models with Second Setpoint, a low level selects setpoint 2. A high level selects setpoint 1.
SPSL or RSP - Local/Remote Select. On models with Secondary Analog
Input, a negative transition engages Remote Setpoint operation and a positive transition engages Local Setpoint operation. The response of the controller to the setpoint transfer is set by the setpoint transfer parameter
“trnF”, under “7-n2” module.
PrNt - Print Request. On models with Serial Communications, a low level transmits the print option selected in the Serial Communications Module
(6-SC). If the user input is held low, after the printing is complete, another request is issued.
