WAGO -I/O-SYSTEM 750 Manual page 101

WAGO-I/O-SYSTEM 750
750-882 Media Redundancy ETHERNET Controller
Example:
Bit access by MODBUS to bit number 4097 => Bit addressing in the PLC
<Word No.>.<Bit No.> = 256.1
The PLC function of the PFC can also access data by bytes and by doubleword
access.
Addresses are calculated based on the following equations for byte-based
access:
Addresses are calculated according to the following equation for double-word
based access:
Additional Information
There is a detailed description of the MODBUS and the corresponding IEC
61131 addressing in section "MODBUS Register Mapping".
High Byte address = Word address*2
Low Byte address = (Word address*2) + 1
Double-word address = High word address/2 (rounded down)
or = Low word address/2
Function Description 101
Manual
1.5.0