Process Image - WAGO 750-457/040-000 Manual

WAGO-I/O-SYSTEM 750 XTR
750-457/040-000 4AI +/-10V DC 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 750-457/040-000 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 voltage range −10 V ... +10 V with a resolution
of 12 bits plus the sign. The measured value is represented in two's complement
binary and the numerical value 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 or underrange, 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 signed 16-bit integer value. The measuring range is then
scaled to the numerical value range of 0x8000 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