Owner's manual

FOUNDATION
TM
Fieldbus Blocks Manual
2-6
Signal Conversion You can set the signal conversion type with the Linearization Type
(L_TYPE) parameter. You can view the converted signal (in percent of
XD_SCALE) through the FIELD_VAL parameter.
You can choose from direct, indirect, or indirect square root signal
conversion with the L_TYPE parameter.
Direct Direct signal conversion allows the signal to pass through the accessed
channel input value (or the simulated value when simulation is enabled).
Indirect Indirect signal conversion converts the signal linearly to the accessed
channel input value (or the simulated value when simulation is
enabled) from its specified range (XD_SCALE) to the range and units of
the PV and OUT parameters (OUT_SCALE).
Indirect Square Root Indirect Square Root signal conversion takes the square root of the
value computed with the indirect signal conversion and scales it to the
range and units of the PV and OUT parameters.
When the converted input value is below the limit specified by the
LOW_CUT parameter, and the Low Cutoff I/O option (IO_OPTS) is
enabled (True), a value of zero is used for the converted value (PV). This
option is useful to eliminate false readings when the differential
pressure measurement is close to zero, and it may also be useful with
zero-based measurement devices such as flowmeters.
NOTE
Low Cutoff is the only I/O option supported by the AI block. You can set
the I/O option in Manual or Out of Service mode only.
Block Errors Table 2-3 lists conditions reported in the BLOCK_ERR parameter.
Conditions in italics are inactive for the AI block and are given here
only for your reference.
FIELD_VAL
100 Channel Value EU*@0%–()×
EU*@100% EU*@0%–()
--------------------------------------------------------------------------------------=
* XD_SCALE values
PV Channel Value=
PV
FIELD_VAL
100
--------------------------------


EU**@100% EU**@0%–()EU**@0%+×=
** OUT_SCALE values
PV
FIELD_VAL
100
--------------------------------


EU**@100% EU**@0%–()EU**@0%+×=
** OUT_SCALE values
TABLE 2-3. BLOCK_ERR Conditions
Condition
Number
Condition Name and Description
0Other
1 Block Configuration Error: the selected channel carries a measurement that is
incompatible with the engineering units selected in XD_SCALE, the L_TYPE
parameter is not configured, or CHANNEL = zero.
2 Link Configuration Error
3 Simulate Active: Simulation is enabled and the block is using a simulated value in
its execution.