CAS CI-170A - Page 64

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FUNCTION 3: Read holding registers
Request
Address
Funcion
Register1
Address
No. register
2 bytes
A
0x03
0x0000
0x0002
CRC
Total. bytes = 8
Reply
Address
Funcion
No.bytes
Register1
Register2
2 bytes
A
0x03
0x04
0x0064
0x00C8
CRC
Total. bytes = 3 + 2*No. register + 2
-number of register = number of modbus register to be read, start at address 1 register.
-number of byte = number of bytes in the following data
FUNCTION 16: Preset multiple registers
Request
Addr
Funcion
Add.
Reg.1
No.reg.
No. bytes
Val. Reg.
1
Val. Reg.
2
2 bytes
A
0x10
0x0000
0x0002
0x4
0x0000
0x0000
CRC
Total. bytes = 7 + 2*No. register + 2
Reply
Address
Funcion
Add.Reg.1
No.reg.
2 bytes
A
0x10
0x0000
0x0002
CRC
Total. bytes = 8
-No. registers = number of modbus register to be read, start at address 1 register
-No. bytes = Number of following data bytes
-Val.reg.1 = Content of starting register
In the reply, the number of converted redcodes starting from address 1 is included.