Red Lion PCU - Manual (Page 32)

User Input (InPt) (Cont’d)
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.
ALrS - Alarm Reset. If the alarm option is installed, a low level resets the
alarm(s) to their inactive state as long as the user input is low.
Prnt - Print Request. A low level transmits the print options selected in the
serial communications module (6-SC). If the user input is held low, after
the printing is complete a second print request is issued.
SPSL - Select Local or Remote Setpoint. On models equipped with Second
Analog Input, configured as Remote Setpoint, a negative transition
engages Remote Setpoint operation and a positive transition engages Local
S e t p o i n t o p e r a t i o n . S e l e c t t h e c o n t r o l l e r o u t p u t r e s p o n s e t o t h e
Local/Remote transfer operation (bumpless, tracking, etc) by the setpoint
transfer parameter (SPtr).
OUTPUT MODULE (2-OP)
The controller has parameters that affect how the main control output
(OP1) responds to process changes and signal overdrive actions.
Time Proportioning Cycle Time (CYCt)
The selection of cycle time depends on the time constant of the process and
the type of output module used.
CYCt - 0 to 250 seconds
For best control, a cycle time equal to 1/10 of the process time constant, or
less is recommended; longer cycle times could degrade process control, and
shorter cycle times provide little benefit at the expense of shortened relay life.
When using a Triac module or a Logic/SSR drive output module with the SSR
Power Unit, a relatively short cycle time may be selected.
A setting of zero keeps the main control output and front panel indicator off.
Therefore, if using the analog output for control, the main output and indicator
can be disabled. This parameter is skipped for Valve Positioner models.
Output Control Action (OPAC)
The main control output (OP1) channel is programmable for reverse acting
or direct acting. Most control applications use reverse acting (See ON/OFF
Control, page 62).
OPAC - rEv (Reverse acting)
drct (Direct acting)
If drct (direct acting) is selected, the main output (OP1) is direct acting and
the secondary output (OP2) is reverse acting. The secondary output always
maintains the opposite setting of the main output.
Note: When using a relay output module, the control action may also be reversed
by using the normally closed contacts.
The linear DC analog output, when assigned to output power (OP) for
control purposes, tracks the controller output power demand. A direct acting
linear output signal can be implemented in two ways:
1. Use “direct” for output control action (OPAC).
2. Interchange the two analog output scaling points ANLO & ANHI (See
Linear DC Analog Output, page 26).
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