Future Design MCTB 4.3, Руководство пользователя

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MCTB
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A.3 Program Recovery Detail
The following will provide a detailed explanation of program recovery operation for the MCTB.
Program Power Recovery
1. Static Mode
When power is cycled the program will be terminated. The control set point and events will return to
the previous static set point and event activation or remain at their current settings if the loop is
configured to use the set points and events of the last step.
2. Continue From SP
When power is cycled the program will resume operation in the same step with the same event
activation and step time that were present at the time of power interruption. The accuracy of time
recovery will be from the beginning of each step and every 5 minutes into the step. The set point;
however, is dependent upon step type.
a. When recovery occurs on a ramp step, the set point and time remaining in the step will return
to the values at the last save interval. If less than 5 minutes into the step, the step will resume
from the beginning of the step. If more than 5 minutes into the step, the step will return to the
last 5 minute interval that elapsed (from the beginning of the step) and resume from the set
point and time remaining at that moment the save occurred.
b. When recovery occurs on a soak step, the set point and time remaining in the step will return
to the last save interval. If less than 5 minutes into the step, the step will resume from the
beginning of the step. If more than 5 minutes into the step, the step will return to the last 5
minute interval that elapsed (from the beginning of the step) and resume from the time
remaining at that moment the save occurred.
3. Continue From PV
When power is cycled the program will resume operation in the same step with the same event
activation that was present at the time of power interruption. The set point and time remaining;
however, are dependent upon step type.
a. When recovery occurs on a ramp step, the program will resume with the control set point equal
to the current process value.
i. If ramp rate units are used (u/min, u/hr), the time remaining will be dependent upon the
programmed ramp rate and the difference between the process value and the target
set point of the step. The time remaining will be recalculated in order to ramp from the
current PV value to the target set point of the step at the programmed ramp rate.
ii. If ramp time units are used (MM.SS or HH.MM), the step will continue ramping from
the current PV value to the target set point of the step in the time remaining at the point
power was lost. This will in effect, alter the ramp rate for the remainder of the step in
order to reach the same set point with what time is left in the step.
b. When recovery occurs on a soak step, the set point and time remaining in the step will return
to the last save interval. If less than 5 minutes into the step, the step will resume from the
beginning of the step. If more than 5 minutes into the step, the step will return to the last 5
minute interval that elapsed (from the beginning of the step) and resume from the time
remaining at that moment the save occurred.