Process Image - WAGO 753-482 Manual

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Process Image

4 Process Image
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 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.
Status information, which can be evaluated in the event of a fault, is contained in
the two least significant bits (B0 and B1). If the measurement is above the
measuring range, Bit B0 is set = 1, and if the measurement is below the
measuring range or if a wire breaks, Bit B0 and B1 are set = 1.
The input voltage range for the measured values of 4 mA to 20 mA is scaled to
the numerical range from 0x0000 to 0x7FFD.
Manual
Version 1.2.0
WAGO I/O System 750
753-482 2AI 4-20mA 12 Bit S.E. HART