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Reference Manual
00809-0100-4697, Rev EA
October 2011
D-15
Rosemount 848T
INPUT SELECTOR
FUNCTION BLOCK
The Input Selector (ISEL) function block can be used to select the first good,
Hot Backup, maximum, minimum, or average of as many as eight input
values and place it at the output. The block supports signal status
propagation. There is process alarm detection in the Input Selector function
block. Table D-6 lists the ISEL block parameters and their descriptions, units
of measure, and index numbers. The block execution time is 30 ms.
IN (1-8) = Input
DISABLE (1-8) = Discrete input used to
disable the associated input channel
SELECTED = The selected
channel number
OUT = The block output and status
OUT_D = Discrete output that signals a
selected alarm condition
SELECTED
OUT
OUT_D
ISEL
IN_1
IN_2
IN_3
IN_4
IN_5
IN_6
IN_7
IN_8
DISABLE_1
DISABLE_2
DISABLE_3
DISABLE_4
DISABLE_5
DISABLE_6
DISABLE_7
DISABLE_8
OP_SELECT
Table D-6. Input Selector Function Block Parameters
Number Parameter Units Description
1 ST_REV None The revision level of the static data associated with the input selector block. The
revision value will be incremented each time a static parameter value in the block
is changed.
2 TAG_DESC None The user description of the intended application of the block.
3 STRATEGY None The strategy field can be used to identify groupings of blocks. This data is not checked
or processed by the block.
4 ALERT_KEY None The identification number of the plant unit. This information may be used in the host for
sorting alarms, etc.
5 MODE_BLK None The actual, target, permitted, and normal modes of the block.
Actual: The mode the “block is currently in”
Target: The mode to “go to”
Permitted: Allowed modes that target may take on
Normal: Most common mode for target
6 BLOCK_ERR None This parameter reflects the error status associated with the hardware or software
components associated with a block. It is a bit string, so that multiple errors may
be shown.
7 OUT OUT_RANGE The primary analog value calculated as a result of executing the function block.
8 OUT_RANGE EU of OUT The engineering units code to be used in displaying the OUT parameter and
parameters which have the same scaling as OUT.
9 GRANT_DENY None Options for controlling access of host computers and local control panels to operating,
tuning, and alarm parameters of the block. Not used by device.
10 STATUS_OPTS None Allows the user to select options for status handling and processing.
11,1 2, 13,
14, 25, 26,
27, 28
IN_(1, 2, 3, 4, 5,
6, 7, 8)
Determined by
source
A connection input from another block