Design And Function; Components Of The Pressure Transmitter; Product Description; Measuring Range Limits And Span Limits - ABB 266CRH Instructions Manual

12 266CRH / 266CRT, 266CSH / 266CST MULTIVARIABLE PRESSURE TRANSMITTER | OI/266CXX/MODBUS-EN REV. A

3 Design and function

Components of the pressure transmitter

1 Housing cover
(terminal compartment)
2 Secondary electronics
3 Transmitter housing
4 Operating buttons
5 Transmitter electronics
Figure 2: Device overview (example)

Product description

The 266Cxx multivariable pressure transmitters measure the
mass flow of gases, vapors, and liquids in accordance with the
differential pressure procedure and the level of the liquids in the
process industry. These transmitters supplies a digital output
signal with Modbus protocol.
Simultaneously and with high accuracy they measure differential
pressure, static pressure and with a Pt100 in four-wire
technology, they also measure the process temperature.
The differential pressure measuring ranges are scaled from
1 to 2000 kPa. The measuring ranges for static pressure are
0.6 to 2 MPa, 10 MPa and 41 MPa.
The transmitters can be overloaded on one side to the
respective upper measuring range value of the static pressure.
Change from two to one column
6 LCD display (option)
7 Housing cover
8 Flanges (process connection)
9 Pressure sensor
j Flange screws and nuts

Measuring range limits and span limits

The data sheets for the Series 2600T multivariable transmitters
contain all the information concerning the measuring range and
measuring span of the individual models, as well as the sensor
code.
The following terminology is used for the different parameters:
Abbreviation Description
URL Measuring range upper limit of a specific sensor.
The highest measured value that can be measured
by the transmitter.
LRL Lower Range Limit of a specific sensor.
The lowest measured value that can be measured by
the transmitter.
URV Upper Range Value.
The highest measured value to which the
transmitter is calibrated.
LRV Lower Range Value.
The lowest measured value to which the transmitter
is calibrated.
SPAN Measuring span.
The algebraic difference between the start of the
measuring range and the end of the measuring
range. The smallest span is the smallest value that
can be selected without impairing the specified
measuring accuracy.
TURN DOWN RATIO Span ratio.
The ration between the maximum span and the
calibrated span.
The measuring transmitter can be calibrated to any measuring
range between LRL and URL with the following restrictions.
• LRL LRV (URL - CAL SPAN)
• CAL SPAN MIN SPAN
• URV URL