Micromod MOD: Modcell 2050R Users Guide - Manual (Page 181)

IB-23C650
RAMP/SOAK OPERATION
Ramp or Soak Hysteresis
The hysteresis function provides for setting up a band of process variable
values relative to the set-point. For example, a temperature hysteresis value
of 10*F provides a band between 290 and 310*F when the set-point is 300*F.
The band also applies to the set-point, preventing a profile from starting if the
set-point is outside the band.
For each profile segment which is configured as guaranteed, the hysteresis
band affects the time duration of the segment because the timer stops when
the process value is outside the hysteresis band. The soak hysteresis value
applies to the set-point of all guaranteed soaks, and segment one when it is a
soak segment. The ramp hysteresis value defines a bandwidth around the
set-point of all guaranteed ramps, and segment one when it is a ramp
segment. For segment one, the ramp or soak hysteresis bandwidth is used to
determine when to start the profile.
The ramp hysteresis prompt [RAMP] [HYST] and the soak hysteresis prompt
[SOAK] [HYST] are tunable functions in the RAMPSOAK MENU. A hysteresis
value (xxxx = 0 to 30000) is selected using the up key and defines a
bandwidth around each guaranteed ramp or soak segment.
Ramp/Soak Hold
The ramp/soak profile can be put on hold while the controller is in automatic
by initiating a [HOLD] in the ramp/soak display sequence of the DISPLAYS
MENU. This sequence is entered by scrolling to obtain RSK in the bottom
status display location. Pressing the up key toggles the profile between RUN
and HOLD. Outside the ramp/soak display sequence this hold is indicated by
an alternating [LOC] and [RSH] in the middle status display location.
In the hold mode, the set-point can be changed using the up or down keys
and the controller may be placed in manual. While in automatic the controller
will control to the new set-point as long as it is in hold. Changing the run/hold
status back to [RUN] causes the controller to continue the ramp/soak profile
where it was when it was placed in hold. If the profile is on the first segment
or a guaranteed segment, the active set-point must be within the hysteresis
band for the profile to start. If it is not, the controller is forced to manual and
the profile is returned to hold.
AUTO/MANUAL TRANSFER WITH RAMP/SOAK
Transfers from automatic to manual or manual to automatic during ramp/soak
operation are made by pressing the auto or manual key. Transfers from
automatic to manual are always bumpless and put the ramp/soak profile into a
paused state. Transfers from manual to automatic result in a bump if the
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