IGS-NT Communication Guide
138
Exceptional response
Byte Meaning Note
0 Controller address Same as in the query
1 134 Function code + 128
2 2 see Error list on page 150
3
4
Check field CRC
lower byte (LSB)
upper byte (MSB)
see Check field calculation on page 143
Write Multiple Registers
Query
Byte Meaning Note
0 Controller address 1 to 32
1 16 Modbus function code
2
3
Communication object number
upper byte (MSB)
lower byte (LSB)
4
5
Communication object length expressed by the number of
registers
upper byte (MSB)
lower byte (LSB)
Greater than 0
6 Length of written data in bytes (L) Number of registers = 2
7
8
Data of the 1st register
upper byte (MSB)
lower byte (LSB)
9
10
Data of the 2nd register
upper byte (MSB)
lower byte (LSB)
...
L + 5
L + 6
Data of the last register
upper byte (MSB)
lower byte (LSB)
L + 7
L + 8
Check field CRC
lower byte (LSB)
upper byte (MSB)
see Check field calculation on
page 143