I-7242D user manual
I-7242D DeviceNet/Modbus RTU Gateway User’s Manual, July 2006, Version 1.1 107/124
Here is an example of correspondences for a full frame, based on the
“Read Holding Registers” Command (0x03).
Element under Utility
Modbus frame fields
Size
(byte)
Modbus Devices Address
Device no.
1
Device I/O Type
Function no.
1
Register Address
No. 1
st
word (MSB/LSB)
2
Modbus
query
Communication Words
No. of words (MSB/LSB)
2
Element under Gateway
Modbus frame fields
Size
(byte)
Modbus Devices Address
Device no.
1
Device I/O Type
Function no.
1
Byte count
No. of bytes read
1
Value of 1
st
word (MSB/LSB)
2
…………………………. …
Modbus
response
Data
Value of last word (MSB/LSB) 2