DCP200 Profile Controller & Recorder -Product Manual
Page 70 Profiler Option 51-52-25-150, Issue 1 –April 2009
The Auto-Hold Feature
Each profile segment has individual Auto-Hold settings. If utilised, these ensure that the
profile and the actual process remain synchronised. If the process does not closely match
the required setpoint by remaining within the defined Hold Band, the profile can be held until
it returns within bounds.
The user can choose to hold the profile if the process goes beyond the Hold Band Above
The Setpoint only, Below The Setpoint only or to Band (either side of the setpoint). When
Auto-Hold becomes active, the profile status is shown as “Held”.
Held if Auto
-
Hold set to
Above Setpoint or Band
Dwell Segment
Setpoint
Hold Band
Process Variable
Held if Auto
-
Hold set to
Below Setpoint or Band
Figure 41. Auto-Hold On A Dwell Segment
During a Dwell, the dwell time is increase by the time that the process is outside of the hold
band in the selected direction(s). This ensures the process was at the desired level for the
required amount of time.
Held if Auto
-
Hold set to
Above Setpoint or Band
Process Variable
Ramp Setpoint
(without Auto-
Hold)
Hold Band
Ramp Setpoint
(with Auto-Hold)
Held if Auto
-
Hold set to
Below Setpoint or Band
Figure 42. Auto-Hold On A Ramp Segment
During a Ramp segment, the ramp is held at the current setpoint value while the process is
outside of the hold band in the selected direction(s). The time taken to complete the ramp is
increased by the time taken by the Auto-Hold.