Despatch P1400+ Temperature Controller - Manual (Page 91)

85
Rate (Derivative) Type: Controller Tuning Parameter
Rate is adjustable in the range 0 seconds (OFF) to 99 minutes 59 seconds. It defines how the
control action responds to the rate of change in the process variable. This parameter should not be
used in modulating value applications as it can cause premature wear due to constant small
adjustments to the valve position. The Rate parameter is not available if primary control output is set
to On-Off.
The Rate parameter is normally set to 0 seconds (OFF) on Valve Motor Drive controllers because
derivative action is not usually desirable in these applications.
Display code =
rAtE , default value = 1.15.
Also refer to On-Off Control , PID , Process Variable , Tuning and Valve Motor Drive Control .
Remote Setpoint (RSP) Type: Controller Definition
Remote Setpoints use the Auxiliary Input option (a secondary analogue input) to adjust a controller’s
setpoint using an external linear DC Voltage or mA input signal, or in some cases potentiometer or
mV inputs. The Remote Setpoint value is constrained by the Setpoint Upper Limit and Setpoint
Lower Limit settings in the same way as a local setpoint. Typical applications are Master/Slave and
Cascade Control.
Display code =
RSP .
Also refer to Auxiliary Input , Cascade Control , Remote Input Range , Remote Setpoint Lower
Limit , Remote Setpoint Upper Limit , Setpoint and Setpoint Select .
Remote Auxiliary Input Range Type: Controller Parameter
Defines the type and range of the linear input signal (mADC, mVDC, VDC or potentiometer) for the
Auxiliary Input. mVDC and potentiometer are only available with the Full Auxiliary input module.
This input can be used for Remote Setpoint or Valve Position Indication
Display code =
RinP , default value =
0_10 0_10 0_10 0_10
for RSP inputs and Pot for Valve Position Indication.
Also refer to Remote Setpoint , Setpoint and Valve Position Indication
Remote Setpoint Lower Limit Type: Controller Parameter
Defines the value of the Remote Setpoint when the RSP input signal is at its minimum value (eg for
a 4 to 20mA RSP, the value when 4mA is applied). It may be adjusted within the range -1999 to
9999; (decimal position same as for process variable input). However, the RSP value is always
constrained within the Setpoint Upper Limit and Setpoint Lower Limits.
Display code =
rSPL , default value = PV input range minimum.
Also refer to Remote Setpoint , Remote Setpoint Input , Remote Setpoint Upper Limit , Remote
Setpoint Offset , Setpoint and Setpoint Upper Limit and Setpoint Lower Limit .
Remote Setpoint Upper Limit Type: Controller Parameter
Defines the value of the Remote Setpoint when the RSP input signal is at its maximum value (eg for
a 4 to 20mA RSP, the value when 20mA is applied). It may be adjusted within the range -1999 to
9999; (decimal position same as for process variable input). However, the RSP value is always
constrained within the Setpoint Upper Limit and Setpoint Lower Limits.
Display code =
rSPu , default value = PV input range maximum.
Also refer to Remote Setpoint , Remote Setpoint Input , Remote Setpoint Lower Limit , Remote
Setpoint Offset , Setpoint and Setpoint Upper Limit and Setpoint Lower Limit .
Remote Setpoint Offset Type: Controller Parameter
Used to adjust the Remote Setpoint input value. Positive values are added to the RSP reading,
negative values are subtracted. It is adjustable in the range –1999 to 9999, but is constrained within
the Scale Range Upper Limit and Scale Range Lower Limit.