Page
31
of
44
3.7
Ramp
The ramping function is performed during power up as well as any time the set point is
changed. Choose MINR (minutes) or HRR (hours) for the “RAMP” setting, and the controller will perform the
ramping function. The ramp rate is programmed by adjusting the “RR” setting. The ramping function is
disabled as soon as Failure mode, Manual control mode, Auto-Tuning mode, or Calibration mode occur.
3.7.1
Example without Dwell Timer
Select MINR for RAMP, set °C for UNIT, Set RR= 10.0. The SV (setpoint) is set to 200°C initially, and
changed to 100°C after 30 minutes from power up. The starting temperature is 30°C. After power up, the
process temperature would follow the curve shown below.
Note:
When the ramp function is used, the lower display will show the current ramping value. However it will
revert to show the set point value as soon as the up or down key is touched for adjustment. The ramp rate is
initiated at power on and/or when the Set point is changed. Setting the RR setting to zero means no ramping
will occur.
3.8
Dwell Timer
The Dwell timer can be used with or without a Ramp. Alarm outputs can be configured as dwell timers by
selecting “dtMR” for the alarm 1 function (A1FN). Similarly, Alarm 2, Alarm3 and Alarm4 will act as dwell
timers if A2FN, A3FN, or A4FN is set to “dtMR”. When the dwell timer is configured, the parameter “DTMR” is
used for dwell time adjustment. The dwell time is measured in minutes ranging from 0.0 to 4553.6 minutes.
The Timer starts to count as soon as the Process Value (PV) reaches its set point (SV), and triggers an alarm
output once the time has elapsed. The dwell timer operation is shown in the following diagram.
After the timer has finished, the dwell timer can be restarted by pressing the RESET key.
The timer stops counting during manual control mode, failure mode, calibration and Auto-Tuning.
If alarm1 is configured as a dwell timer, A1HY and A1MD are hidden. It is similar for other alarms as well.
