Introduction To Ramp/Soak Profile Control - ABB COMMANDER 1900 Series User Manual

2.1 Introduction to Ramp/Soak Profile Control – Fig. 2.2
Information.
• 10 programs per control channel.
• Digital State program selection – allows digital inputs to select program to be run.
• 99 programmable segments – can be shared between programs and controllers – see Fig. 2.3.
• Programmable time units – can be programmed in hours or minutes.
• Program repeat – 0 to 99 times or continuously.
• Program holdback hysteresis – for guaranteed ramps and soaks.
• 5 types of ramp/soak generated events – segment active event, program active event, end of program event,
holdback event and hold active event.
• 6 ramp/soak commands – can be selected from the front panel or via digital signals to run/hold programs, reset
programs, skip forward to next segment, skip backwards to beginning of segment, increase soak time or decrease
soak time (refer to Fig. 2.4 for ramp/soak adjust example).
• Self-seeking set point function – avoids unnecessary delays when a program is started – see Fig. 2.5.
• Retort function – ensures safe operation under fault conditions – see Fig. 2.6.
• Power recovery function – determines ramp/soak profile restart position on instruments fitted with the Timer option.
The Ramp/Soak option is a set point profile generator which controls the Local set point and can be used with any type of control
process for more complex control. A Profile Program is made up of Ramps (the set point is increased or decreased at a linear rate
until it reaches the desired value) and Soaks (the set point is maintained at a fixed value for a set time duration).
Fig. 2.2 shows a typical Ramp/Soak Profile and some of its features.
Adjustable Rate of Rise
Set Point
(Eng. Units)
Adjustable Holdback
Hysteresis Bandwidth
Set Point
Process
Skip Forward
Manual Pause
Start of
Profile
Holdback Active
Seg. 1 Seg. 2 Seg. 3
Fig. 2.2 Typical 6-segment Ramp/Soak Profile
2 CONTROL CONFIGURATION LEVEL...
Seg. 4 Seg. 5
Event
Relay On*
Time (Hours or Minutes)
• Ramp/Soak
Adjustable Rate of Fall
End of Profile
(switch to Local Set
Point or Repeat)
Start of Next
Profile
Optional Repeat
Start Next Cycle
*Segment 4 Assigned to Relay
3