Future Design MCTB 4.3, Руководство пользователя

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MCTB
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10.1 Power Recovery
The Power Recovery setting allows the user to select how the system should restart in the event of a power
failure while an automatic ramp/soak program was running. When power is restored, the MCTB will perform
the selected recovery action. To set the power recovery action, push the recovery mode button for the desired
setting to select it as the power-up state. The selections are mutually exclusive to one another, i.e., only one
can be selected at a time. As a new selection is made, the previous setting will be automatically turned off.
Select
Continue from SP to have the MCTB resume the program from where it left off on loss of power. The
set point ramp will continue from the set point value at the time of power interruption.
Select
Continue from PV to have the MCTB resume the program from where it left off on loss of power. The
set point ramp will continue from the current process value of the loop and not the last set point value.
Select
Static Mode to have the MCTB default to single set point operation on power-up. The program will be
stopped and the loops will control to the last static set point entry.
NOTE: When a program is NOT running and a power down/up sequence occurs, the MCTB will return with
the same set points and system events active as when the power was lost.
See Appendix section A.3 Profile Recovery Detail for a more detailed explanation and
examples of program recovery operation.
10.1.1 Recovery Interval
During program operation, the current program progress is stored in memory on each step change and at 5-
minute intervals during step operation. During static set point operation, the current control set point and events
are stored to memory within 15 seconds after a change is made.
For program operation, this results in a possible recovery error of up to 5 minutes. For example, a program is
running and enters step 2 which is a ramp step from 0 to 100 degrees in 10 minutes. If power is lost at 4
minutes into the step and
“Continue from SP” is the selected recovery mode, when power is restored the
program will begin operation from the beginning of step 2 with a set point of 0. It will not resume operation from
50 degrees at 4 minutes into the step.
If the power is lost at 8 minutes into the step (2 minutes remaining), the program will continue from the last save
point which was 5 minutes into the step (5 minutes remaining) with a set point of 50 degrees. For soak steps
the set point remains a constant and time remaining is the only variable. So as with the ramp step, the time
remaining in the step will continue from the last save point.