Chatsworth Products Remote Infrastructure Management System Protocol Converter - Manual (Page 53)

RIM-Protocol Converter User Guide - Version 1.0
Chatsworth Products, Inc. (CPI) • 800-834-4969 53
Table 4.2 Read Output Registers Packet Structure
Table 4.3 Output Registers
4.3 RTU Framing
The example below shows a typical Query/Response from an Protocol Converter.
Table 4.4 Response Sample
Slave address 2 responds to Function Code 4 with six bytes of hexadecimal data and ends with CRC16 checksum.
Register Values:
40001 = 0000 (hex)
40002 = 0000 (hex)
40003 = 0001 (hex)
Code Name Description Units Range
40001 Integer Output Register for Integer data 16 0-65535
42001
Float Output
* two registers need
Register for Float data 32 0-65535
Read Registers Request Packet Read Registers Response Packet
Slave Address (1 byte) Slave Address (1 byte)
03 (Function code) (1 byte) 03 (Function code) (1 byte)
Start Register (2 bytes) Byte count (1 byte)
# of registers to read (2 bytes) First register (2 bytes)
CRC Checksum (2 bytes) Second register (2 bytes)
…
CRC Checksum (2 bytes)
Slave
Address Function
Code Count Bytes
of Data Register
Data
Msb Lsb Register
Data
Msb Lsb Register
Data
Msb Lsb CRC 16
“Lsb” CRC 16
“Msb”
02 04 06 00 00 00 00 00 01 B5 A3