Future Design MCT-MC 4.3, Руководство пользователя

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MCT-MC
4.3
FDC MCT-MC - 68 - Automatic Program Operation
NOTE: The step events must be set individually for each step. Even though a ramp/soak program may be in
operation, if the events are not set, the associated loop control output will not turn on. To make setting
step events quick and easy, the MC provides the “Step Events” function from the “Edit” menu. When
selected, all event selections of the current step will be copied to all following steps.
6.1.4 Setting Hold Events
The hold event is used to turn on the holdback option for the loop control. To edit the hold event, press the
“Hold” button on the program Entry screen. This will display the Hold list for the program step.
Pressing the on/off button will toggle holdback on and off for the loop. When the hold event is enabled, the
program will automatically enter a hold condition during the step if the loop’s process value deviates from its
set point by more than the holdback limit setting for the program.
NOTE: When running an automatic program in the “All” mode, only the primary loop is monitored for the
holdback condition. All additional (slave) loops are not monitored for holdback. If there is a need to
monitor the slave loops and place the program in hold if they deviate too far from set point, it will be
necessary to configure the slave loops with deviation alarm outputs.
The deviation alarm outputs can then be wired into the event input of the primary loop. With the event
input of the primary loop configured as an “automatic program hold” input, the program running in the
primary loop will be placed in hold whenever a slave loop deviates too far from set point. When the
deviation alarm deactivates, the program will then resume operation. Note that the deviation alarm
set points for each loop will have to be manually entered to match the holdback limit as set in the
running program.
6.1.4.1 HoldBack Limits
The holdback limit setting is used to set the control tolerance for the loop during steps that have hold back
enabled. When the loop process variable deviates from its set point by more than the band value (above or
below set point), the program timer will stop until the process variable re-enters the hold back band. The
Holdback Limits are accessed from the Edit pop-up menu. The entry applies to every step in the program and
only needs to be entered once for the program.
When the event is turned on
in a step, an asterisk ‘*’ will
appear before the word
“Hold” on the list selection
button.
This indicates that holdback
is enabled without having to
press the “Hold” button to
display the holdback event
list.