Red Lion PCU - Manual (Page 34)

Auto-Tune Dampening Code (tcod)
Prior to invoking Auto-Tune, the dampening code should be set to achieve
the desired dampening level under PID control. After Auto-tune is complete,
changes to “tcod” parameter have no effect until Auto-tune is re-started.
When set to 0, this yields the fastest process response with possible
overshoot. A setting of 4 yields the slowest response with the least amount of
overshoot. Dampening codes of 0 or 1 are recommended for most processes.
Linear DC Analog Output (ANAS, ANLO, ANHI, ANdb, ANUt)
(Optional)
The Linear DC output can be programmed to transmit one of the following
controller parameters:
ASSIGN DC OUTPUT (ANAS):
OP
– Percent output power
INP – Scaled input process value
dEV – Process setpoint deviation
SP – Process setpoint value
dE-2 – Process deviation of secondary loop (Internal Cascade only)
SP-2 – Process setpoint of secondary loop (Internal Cascade only)
With high and low digital scaling points, the range of the Linear DC output
can be set independent of the controller’s range. This allows interfacing
directly with chart recorders, remote indicators, slave controllers, or linear
power control units.
ANLO (4 mA or 0 VDC) – -999 to 9999
ANHI (20 mA or 10 VDC) – -999 to 9999
Linear DC output deadband (ANdb) and linear DC output update time
(ANUt) parameters are additional parameters used for control purposes
(ANAS=OP). The deadband parameter requires that the output power, in
percent, must change more than the deadband amount in order for the output
to update. A value of 0.0 disables the deadband action. The linear output
update time updates the output at the time interval specified. A value of 0
seconds updates the output at the controller’s scan rate (10/sec). In the manual
mode of operation both parameters are overridden. The front panel indicator
OP1 and main output can be disabled by setting the time proportioning cycle
time equal to zero (CYCt = 0).
Note: Valve Position controllers disable the “OPEN” and “CLOSE” outputs
when the linear DC output is assigned to output power. In this case, the
slidewire feedback signal may be used to verify valve position.
ANdb – 0.0 to 25.0%
ANUt – 0 to 250 seconds
For setpoint transmission, (external cascade control used with another
controller), the controller transmits the instantaneous ramping setpoint, not
the target value, when the controller is ramping the setpoint. For models
with Remote Setpoint, the linear output transmits the active setpoint (local
or remote).
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Figure 14, Dampening Code