Red Lion TCU - Manual (Page 35)

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).
Example: Chart Record Process Display Value (0 to 10 VDC):
The process range is 300-700. Programming 300 for ANLO (0 VDC
value) and 700 for ANHI (10 VDC value) yields full scale deflection for a
chart recorder (0 to 10 VDC). The 0 to 10 VDC output is assigned to
transmit the input reading (ANAS = INP).
Example: Linear Control Output (4 to 20 mA)
A linear DC input power control unit is used for process control. An
output control deadband of ± 2.0% and an output update time of 10 seconds
is desired. The following set-up values illustrate the configuration:
ANAS = OP
ANLO = 0.0%
ANHI = 100.0%
ANdb = 2.0%
ANUt = 10 seconds
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Figure 15, Linear DC Output