12 •
750-455(/xxx-xxx) [4 AI 4-20 mA, Single-Ended]
Process Image
WAGO-I/O-SYSTEM
750
I/O
Modules
2.1.1.7 Process
Image
The analog input module 750-455 transmits 16-bit measured values and
8 optional status bits per channel.
The digitalized measured value is transmitted in a data word (16 bits) as input
byte 0 (low) and input byte 1 (high) into the process image of the coupler /
controller.
This value is represented with a 12 bit resolution on bit B3 ... B14.
The status information included in the two least significant bits (B0 ... B1) can
be parsed in the event of an error. Bit B0 and B1 = 1 are set when the range of
measurement is overranged or underflow or broken wire. Bit B2 is not defined
and not evaluated. Therefore, they are represented with a ‘X‘ in the table.
Some fieldbus systems can process input channel status information by means
of a status byte.
This status byte can be displayed using the starting tool WAGO-I/O-CHECK
2. However, the coupler / controller process operation is optional, which
means that accessing or parsing the status information depends on the fieldbus
system.
Attention
The representation of the process data of some fieldbus modules or their
variations 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 of the process image of the
corresponding coupler/controller.
