Example¶

Example:¶
MODBUS interface of the client	COM1
Client reads from	Server 1
Data	%MD0.8193 = 32DEC = 00000020HEX %MD0.8194 = 80000DEC = 00013880HEX
Source address at server	%MD0.8193: 4002HEX = 16386DEC
Target address at client	adwReadDWord : ARRAY[0..1] OF DWORD
The values of the flag double words %MD0.8193..%MD0.8194 on the server are written to the ARRAY adwReadDWord on the client.

MODBUS request of the client¶
Server address	Function code	Server operand address		Number of words		CRC
Server address	Function code	High	Low	High	Low	High	Low
01HEX	03HEX	40HEX	02HEX	00HEX	04HEX	F0HEX	09HEX

MODBUS response of the server¶
Server address	Function code	Number of bytes	Data	Data	Data	Data	CRC
Server address	Function code	Number of bytes	High / Low	High / Low	High / Low	High / Low	High	Low
01HEX	03HEX	08HEX	00HEX /00HEX	00HEX /20HEX	00HEX /01HEX	38HEX /80HEX	57HEX	B0HEX

Parameterization \ of the COM_MOD_MAST Function Block inputs¶
EN	COM	SLAVE	FCT	TIMEOUT	ADDR	Number of words	DATA
FALSE -> TRUE	1	1	3	Application- specific	16386	4	ADR (adwReadDWord[0])