ComAp Inteli Mains NT BaseBox, Руководство по связи, Страница: 136 / 152

IGS-NT Communication Guide
136
Read Multiple Registers
Query
Byte Meaning Note
0 Controller address 1 to 32
1 3 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
7
Check field CRC
lower byte (LSB)
upper byte (MSB)
see Check field calculation on
page 143
Standard response
Byte Meaning Note
0 Controller address Same as in the query
1 3 Same as in the query
2 Length of read data in bytes (L) Number of registers * 2
3
4
Data of the 1st register
upper byte (MSB)
lower byte (LSB)
5
6
Data of the 2nd register
upper byte (MSB)
lower byte (LSB)
...
L + 1
L + 2
Data of the last register
upper byte (MSB)
lower byte (LSB)
L + 3
L + 4
Check field CRC
lower byte (LSB)
upper byte (MSB)
see Check field calculation on page 143