Reference Manual
00809-0100-4697, Rev EA
October 2011
Rosemount 848T
A-4
FUNCTION BLOCKS
Analog Input (AI)
• Processes the measurement and makes it available on the
fieldbus segment.
• Allows filtering, alarming, and engineering unit changes.
Input Selector (ISEL)
• Used to select between inputs and gener ate an output using specific
selection strategies such as minimum, maximum, midpoint, or aver age
temperature.
• Since the temperature value always contains the measurement st atus, this
block allows the selection to be restricted to the first “good” measurement.
Multiple Analog Input Block (MAI)
• The MAI block allows the eight AI blocks to be multiplexed together so
they serve as one function block on the H1 segment, resulting in greater
network efficiency.
PERFORMANCE
SPECIFICATIONS Stability
• ±0.1% of reading or 0.1 °C (0.18 °F), whichever is greater, for 2 years
for RTDs
• ±0.1% of reading or 0.1 °C (0.18 °F), whichever is greater, for 1 year for
thermocouples.
Self Calibration
The transmitter’s analog-to-digital circuitry automatically self-calibrates for
each temperature update by comparing the dynamic measurement to
extremely stable and accurate internal reference elements.
Vibration Effect
Transmitters are tested to high pipeline vibration specification per IEC
60770-1 1999 with no effect on per formance.
Electromagnetic Compatibility Compliance Testing
• Meets the criteria under IEC 61326:2006
• Meets the criteria under European Union Directive 2004/108/EC