West Control Solutions Pro-EC44 - Manual (Page 96)

Pro-EC44 2-Loop Graphical Profile Controller & Recorder
Pro-EC44 Product Manual - 59540-1 October 2013 Page 89
Note: If the join target has been deleted the profile sequence will abort and the
last profiles abort action will apply.
Two Loop Profiles
If the instrument is configured to control two control loops, the setpoint of both loops can be
maintained when profiling. Both setpoints are synchronised to a common segment time-
base, but have independent target setpoints for each of the segments.
Note: When using the instrument as a two loop profiler Ramp-Rate type
segments are not available. Calculate the time from the starting value to the
target setpoint and use Ramp-Time instead.
The example below shows how two loop profiling works in practice.
Auto-Hold settings and target setpoints are independent for each loop, but the segment types
and time settings are the same.
2-LOOP PROFILE
Independent
Setpoints
Loop 1
Loop 2
Seg. Nos
Both loops on same time-base
Seg.
① & ② shows a ramp and a dwell with the shared time base
The ramp direction can be different (Seg.
③), and although one loop cannot ramp while the
other dwells, a "dwell" is achieved by a ramp with its final setpoint value at the same value as
the previous segment (Seg.
④). Similarly, if only one loop is to Step to a new value, make
the other “step” to its existing setpoint value. If you later change the previous setpoint, you
may have to change both segments.
The Loop-back feature takes both loops back to the same defined earlier segment.
Note: Auto-Hold settings are independent for each loop. Either loop can cause
the profile to auto-hold, holding both loops at the current setpoint value. The
profile continues only when both loops are back within their hold bands.