Samwontech TEMI2000 Series, Communications Manual

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SAMWONTECH
1st Edition of TEMI2000_Series IM : Dec. 15. 2008 Page 20 / 58
6.3 Function code - 03
Function code-03 is used to read the data of consecutive D-Register block in sequence up to 64 registers.
▣
Request Message Frame
Factor ASCII RTU
Protocol Header :(Colon) -
Slave Address 2 characters 8-Bit
Function code-03
2 characters
8-Bit
D-Register Hi
2 characters
8-Bit
D-Register Lo 2 characters 8-Bit
Address Count Hi
2 characters
8-Bit
Address Count Lo
2 characters
8-Bit
Error detecting
2 characters
16-Bit
Protocol Tail 2 characters (CR+LF) -
◈ Exmaple
Request message to read the D-Register FROM D0001 (TEMP.PV) TO D0002 (TEMP.SP) should be
- MODBUS ASCII
:010300000002FA[cr][lf]
- MODBUS RTU 010300000002C40B
☞
D-Register has to be subtracted ‘1’ from the designated address number on D-Register table in this manual.
▣
Response Message Frame
Factor ASCII RTU
Protocol Header :(Colon) -
Slave Address 2 characters 8-Bit
Function code-03
2 characters
8-Bit
Data byte count
2 characters
8-Bit
Data - 1 Hi 2 characters 8-Bit
Data - 1 Lo 2 characters 8-Bit
… … …
Data - n Hi
2 characters
8-Bit
Data - n Lo 2 characters 8-Bit
Error detecting 2 characters 16-Bit
Protocol Tail 2 characters (CR+LF) -
◈
Example
Response data will be same as below, when 49.3 of D0001 (TEMP.PV) and 10.8 of D0002 (TEMP.SP)
- MODBUS ASCII
:01030401ED006C9E[cr][lf]
- MODBUS RTU 01030401ED006C6BD7