Process Image - WAGO 750-484 Manual

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Process Image

4 Process Image
Mapping of process data in the process image of fieldbus systems
The representation of the I/O modules' process data in the process image depends
on the fieldbus coupler/controller used. Please take this information as well as the
particular design of the respective control/status bytes from the section "Fieldbus
Specific Design of the Process Data" included in the description concerning the
process image of the fieldbus coupler/controller used.
Evaluation of Status Byte
Some fieldbus systems can process status information of process value by means
of a status byte.
This status byte can be displayed via the commissioning tool WAGO-I/O-
CHECK.
However, processing via the fieldbus coupler/controller is optional, which means
that accessing or parsing the status information depends on the fieldbus system.
The HART I/O Module provides the fieldbus coupler/controller with a different
amount of process data depending on the operating mode set.
Some fieldbus systems process status information on the input channel with the
help of a status byte.
This status byte can be displayed using the WAGO-I/O-CHECK 2 commissioning
tool but processing by the coupler/controller is optional; i.e., access to or
evaluation of the status information depends on the respective fieldbus system.
Mapping of the Process Image in the Fieldbus System!
Mapping the process data of some I/O modules (or their variations) into the
process image is specific to the fieldbus coupler/controller used. This information,
as well as the specific configuration for relevant control/status bytes is located in
the section "Fieldbus-Specific Configuration of Process Data." This section
describes the process image of the particular coupler/controller.
For pure 4 mA ... 20 mA analog values the HART module transmits 16-bit
measured values and optionally 8 status bits on each channel.
The digitalized measured value is transmitted to the process image of the
coupler/controller in a data word (16 bits) as an input byte 0 (low) and input byte
1 (high).
This value is mapped with a resolution of 13 bits on Bit B2 ... B14.
WAGO-I/O-SYSTEM 750
750-484 2 AI 4-20 mA HART Ex i
V 1.2.0 HW-Version 04, SW-Version 03
Manual