Table of Contents
Advertisement
5.2.4.16 Ramp & Dwell
5.2.4.16.1.1 Ramp
The ramping function is performed during power up as well as any time the set point is changed. Choose
MINR or HRR for SPMD, the unit will perform the ramping function. The ramp rate is programmed by using
RAMP which is available in user configuration of Process Control Card
Example without Dwell Timer
Select MINR for SPMD, IN1U selects °C, DP1 selects 1-DP, Set RAMP=10.0. SP1 is set to
200°C initially, and changed to 100°C after 30 minutes since power up. The starting temperature is 30° C.
After power up the process is running like 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 ramping
value is initiated to process value either power up or RAMP and /or set point are changed. Setting RAMP to
zero means no ramp function at all.
5.2.4.16.2 Dwell
The Dwell timer can be used separately or accompanied with a Ramp. If A1FN selects TIMR,
the alarm 1 will act as a dwell timer. Similarly, alarm 2 will act as a dwell timer if A2FN selects TIMR. The
timer is programmed by using TIME which is contained in Configuration menu. The Timer starts to count as
soon as the process reaches its set point, and triggers an alarm as time out. Here is an example.
Example with Dwell Timer
Select TIMR for A1FN, IN1U selects F, DP1 selects NODP, Set TIME=30.0 SP1 is set to 400 F
initially, and corrected to 200 F before the process reaches 200° F. As the process reaches set point (i.e.
200°F) the timer starts to count. The TIME value can still be corrected without disturbing the Timer before
time out. The TIME is changed to 40.0 after 28 minutes since the process reached its set point. The
behaviour of process value and alarm 1 are shown below. Once the timer output was energized it will
remain unchanged until power down or an event input programmed for resetting alarm is applied.
Note: The TIMR can't be chosen for both A1FN and A2FN simultaneously; otherwise an error code will
produce.
5.2.4.16.3 Ramp &Dwell
A Ramp can be accompanied with a dwell timer to control the process. Here is an example.
Example Ramp & Dwell Timer
Page 147 of 479
Advertisement
Table of Contents
