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PROFILE 1
PROFILE 9
Seg. 1 Target SP
Ramp (Time/Rate)
Starting Setpoint
Start
Trigger
Step
End
Timer or Delay Dwell
Join (Profile 1 to Profile 9)
Figure 49. Profile Starting and Standard Segment Types
Ramps and Step Segments have target setpoint that
they will reach as they finish. If a segment is a Ramp-
Time type, the slope needed to reach the target set-
point in the defined time will change depending on the
starting setpoint value. For a Ramp-Rate segment, the
slope is defined by the segments Ramp Rate, so the
time to reach the target setpoint will change instead.
This is of particular significance for the first segment,
since the starting value of the process may not be
known in advance.
Note:
When using the instrument as a two loop pro-
filer Ramp-Rate type segments are not available.
Calculate the time from the starting value to the
target setpoint and use Ramp-Time instead.
A Dwell (often called a “soak”) holds the previous setpoint
value for the specified dwell time. Step segments jump
straight to the new target setpoint value. An End segment
ends the profile or profile sequence. If the last segment is
a Join, the “join target” profile will begin running.
Note:
If the join target has been deleted the profile
sequence will abort and the last profiles abort ac-
tion 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 synchronized 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 pro-
filer 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 set-
points are independent for each loop, but the segment
types and time settings are the same.
Seg.
u
&
v
shows a ramp and a dwell with the shared
time base The ramp direction can be different (Seg.
w
),
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 seg-
ment (Seg.
x
). Similarly, if only one loop is to Step to
a new value, make the other “step” to its existing set-
point 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.
Summary of Contents for Chromalox 4081
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