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Reference Manual
00809-0400-4728, Rev AA
June 2011
Rosemount 644
3-10
L_TYPE
The L_TYPE parameter defines the relationship of the sensor
measurement (sensor temperature) to the desired output temperature of
the AI Block. The relationship can be direct or indirect.
Direct
Select direct when the desired output will be the same as the sensor
measurement (sensor temperature).
Indirect
Select indirect when the desired output is a calculated measurement
based on the sensor measurement (e.g. ohm or mV). The relationship
between the sensor measurement and the calculated measurement will be
linear.
XD_SCALE and OUT_SCALE
The XD_SCALE and OUT_SCALE each include four parameters: 0%,
100%, engineering units, and precision (decimal point). Set these based
on the L_TYPE:
L_TYPE is Direct
When the desired output is the measured variable, set the XD_SCALE to
represent the operating range of the process. Set OUT_SCALE to match
XD_SCALE.
L_TYPE is Indirect
When an inferred measurement is made based on the sensor
measurement, set the XD_SCALE to represent the operating range that
the sensor will see in the process. Determine the inferred measurement
values that correspond to the XD_SCALE 0 and 100% points and set
these for the OUT_SCALE.
NOTE
To avoid configuration errors, only select Engineering Units for XD_SCALE
and OUT_SCALE that are supported by the device. The supported units
are:
When the engineering units of the XD_SCALE are selected, this causes
the engineering units of the PRIMARY_VALUE_RANGE in the Transducer
Block to change to the same units. THIS IS THE ONLY WAY TO CHANGE
THE ENGINEERING UNITS IN THE SENSOR TRANSDUCER BLOCK,
PRIMARY_VALUE_RANGE parameter.
Pressure (Channel 1) Temperature (Channel 2)
°C °C
°F °F
K K
R R
mV mV