Red Lion TSC - Manual (Page 34)

OUTPUT MODULE (2-OP)
The controller has parameters which affect how the main control output
(OP1) responds to temperature changes and sensor failures.
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 120 seconds
For best control, a cycle time equal to 1/10 of the process time constant is
recommended; longer cycle times could degrade temperature control, and
shorter cycle times will 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.
Output Control Action (OPAC)
For heat and cool applications, the main output (OP1) should be used for
heating (reverse acting) and the optional cooling output (OP2) should be used
for cooling (direct acting).
OPAC - rEv (Reverse acting)
drct (Direct acting)
If drct (direct acting) is selected, the main output (OP1) is direct acting and
the cooling output (OP2) is reverse acting.
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, will always follow 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 in the output parameter module section).
Output Power Limits (OPLO & OPHI)
Enter the safe output power limits for the process. These parameters may
also be used to limit the minimum and maximum controller power due to
process disturbances or setpoint changes to reduce overshoots by limiting the
process approach level.
OPLO & OPHI - 0 to 100%
If the cooling option is installed, the limits range from:
OLO & OPHI - -100 to 100%
With the cooling option installed, the Lower Limit can be set to less than 0%
to limit maximum cooling or set to greater than 0% to limit minimum heating.
Set the High Limit to less than 0% to limit minimum cooling or greater than
0% to limit maximum heating. When controlling power in the manual mode,
the output power limits do not take affect.
Sensor Fail Preset Power (OPFL)
If a failed sensor is detected, the control output(s) default to a preset
power output.
OPFL - 0% (OP1 output full “off”) to 100% (OP1 output full “on”)
If the cooling option is installed, the range is extended from:
OPFL - -100% to +100%
At 0% both outputs are off, at 100% OP1 is on and OP2 is off, and at -100%
OP2 is on and OP1 is off. The alarm outputs always have an up-scale drive
(+9999), independent of this setting, for failed sensor.
ON/OFF Control Hysteresis Band (CHYS)
The controller can be placed in the ON/OFF control mode by setting the
proportional band to 0.0%. The control hysteresis value affects only the main
control output (OP1).
CHYS - 1 to 250 degrees
The hysteresis band should be set to a minimum value to eliminate output
chatter at the setpoint. Generally, 2 to 5° is sufficient for this purpose. Set the
hysteresis band to a sufficient level prior to invoking Auto-Tune.
-32-