Micromod MOD: Modcell 2050R Users Guide - Manual (Page 175)

IB-23C650
RAMP/SOAK OPERATION
RAMP/SOAK OPERATION
DESCRIPTION OF RAMP/SOAK PROFILE
The Ramp/Soak Profile option complements any type of control
implementation by adding a ramp/soak set-point profile with up to 10 ramp or
soak segments. The ramp function changes the local set-point up or down at
a specified rate. The soak function maintains the set-point at a fixed value for
a specified period of time. Figure 19 shows a typical profile and some of its
features. The profile is run in either hours or minutes and each segment can
contain up to 30,000 units of time. Ramp/Soak features include: repeating a
profile, resetting a profile, skipping segments, guaranteed ramps and soaks,
and three segment event states using output relays A, B and C. When all
three event states are enabled, high or low alarm outputs are not available.
The process variable may be either a temperature or electrical input. When
ramp/soak is running with the controller in automatic, the control algorithm
receives an active local set-point which changes as a function of the
ramp/soak profile. The control algorithm performs its normal function of
calculating an output which will bring the process variable to the set-point
based on the configuration of the P, I, D, or on/off responses.
When the controller is in automatic, ramp/soak can be set for either run or hold
using the scroll and up/down keys. When ramp/soak is on hold, the set-point
can be adjusted using the up/down keys. When ramp/soak is switched back
to run, the profile is started at the point where it was held. When the switch is
made, any difference between the adjusted set-point value and the profile
value causes a step change in the active set-point.
When control is switched to manual, the ramp/soak profile pauses and the
output value can be changed via the up/down keys. Output adjustment while
in manual is from 0 to 100% of span. The switch from manual back to
automatic is not bumpless. If the process value is at 70% in manual and the
ramp or soak profile segment calls for 80%, the switch to automatic
immediately causes the process to begin changing to the 80% value.
When ramp/soak is running, the remote set-point cannot be made active and
autotune cannot be entered. If the remote set-point is active, ramp/soak
cannot be started in the DISPLAYS MENU.
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