Process Image - WAGO 750-453/040-000 Manual

WAGO-I/O-SYSTEM 750 XTR
750-453/040-000 4AI 0-20mA S.E. /XTR

Process Image

4
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.
The I/O module provides 1 status byte (8 bits) and 1 data word (16 bits) per
channel.
Whether the status byte is read out via the fieldbus depends on how diagnostic
information is transmitted by the respective fieldbus or fieldbus
couplers/controllers used. In any case, the status byte can be read out using the
WAGO-I/O-CHECK commissioning tool via the service port of the fieldbus
coupler/controller.
The I/O module detects the input current range 0 mA ... 20 mA with a resolution
of 12 bits. The measured value is mapped to bits B15 ... B3 of the data word.
Bits B1 and B0 carry diagnostic information, bit B2 is reserved and has no
defined value. If the measuring range is overrange, the I/O module transmits the
next displayable measured value and sets B0 and B1 to the value 1.
Simplified interpretation of the measured value!
The measured value can also be easily obtained in that the complete data word
is interpreted as a 16-bit integer value. The measuring range is then scaled to the
numerical value range of 0x0000 to 0x7FFF. The decimal places of the resulting
analog value corresponding to the lower three bits, however, must be ignored.
Process Image 33
Manual
Version 1.3.0