Emerson Fisher FIELDVUE DVC6000f, Инструкция по эксплуатации, Страница: 164 / 384

DVC6000f Digital Valve Controllers
December 2009 4-104
fieldbus
−
fbus_229a
IN_1
IN_2
IN_3
IN_4
DISABLE_1
DISABLE_2
DISABLE_3
DISABLE_4
OP_SELECT
Selection
Algorithm
AUTO
MAN
OUT
SELECTED
MIN_GOOD
SEL_TYPE
Figure 4-14. Input Selector Function Block Schematic
SELECT_TYPE
NOTE: THIS FIGURE DOES NOT
INCLUDE THE ADDITIONAL 4 INPUTS
IN THE EXTENDED PARAMETERS.
For a selection algorithm to use an input with
status of Uncertain, the STATUS_OPTS [10]
parameter must have “Use Uncertain as Good.”
STATUS_OPTS [10] is applied before selection.
If the number of good inputs is less than
MIN_GOOD [20], or if the number of inputs evaluated
is 0, the status of OUT [7] and SELECTED [21] will be
Bad.
If an input is disabled or its status is Bad and is
selected via OP_SELECT [22], then the status of OUT
[7] and SELECTED [21] will be Bad. If the quality of
the input is Uncertain, and the selection for the
STATUS_OPTS [10] parameter is “Use Uncertain as
Good,” then the status of OUT [7] and SELECTED
[21] will be Uncertain. Otherwise the status of OUT [7]
and SELECTED [21] will be Good Noncascade.
When the block is in the Manual mode the status and
substatus of OUT [7] and SELECTED [21] will be as
follows:
Substatus will be non-specific and the limit will be
constant.
Quality of OUT [7] and SELECTED [21] will be
Uncertain if STATUS_OPTS [10] is “Uncertain if in
Manual mode.” Otherwise, the quality of OUT [7] and
SELECTED [21] will be Good Noncascade.
Limit Propagation
Refer to figure 4-15. When SELECT_TYPE [19] is
Average, Not Limited is propagated unless all inputs
have the same limit status. If all inputs have the same
limit status, the limit status of the inputs is propagated.
If SELECT_TYPE [19] is Middle and the number of
inputs used by the algorithm is greater than one: Not
Limited is propagated unless all selected inputs have
the same limit status, in which case the limit status of
the inputs is propagated.
If SELECT_TYPE [19] is Middle and a single input, or
if Maximum or Minimum then: If the selected input is a
constant and Middle, Constant is propagated.
Otherwise, if the selected input is a constant and
Maximum or Minimum, propagate low if Maximum,
propagate high if Minimum. If the selected input is not
a constant, propagate selected input limit as is.
When SELECT_TYPE [19] is First Good or Hot Spare
or if OP_SELECT [22] is non-zero, propagate selected
input limit as is.
Substatus Propagation
Refer to figure 4-16. For SELECT_TYPE [19] of
Maximum, Minimum, First Good, Hot Spare, and
Middle with only one input, simply propagate substatus
as is.
For SELECT_TYPE [19] of Maximum and Minimum
with more than one input with the same value,
propagate substatus if all inputs are the same.
For SELECT_TYPE [19] of Average or Middle with
more than one input, propagate NonSpecific.
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