Example¶

Example:¶
MODBUS interface of the client	COM1
Client writes to	Server 1
Data	adwWriteDWord[0] := 18DEC = 00000012HEX; adwWriteDWord[1] := 65561DEC = 00010019HEX;
Source address at client	adwWriteDWord : ARRAY[0..1] OF DWORD;
Target address at server	%MD0.8192 : 4000HEX = 16384DEC
The values of the Double WORD variables adwWriteDWord[0].. adwWriteDWord[1] on the client are written to %MD0.8192..%MD0.8193 on the server.

MODBUS request of the client¶
Server address	Function code	Server operand address	Number of words	Number of bytes	Data	Data	Data	Data	CRC
Server address	Function code	High / Low	High / Low		High / Low	High / Low	High / Low	High / Low	High / Low
01HEX	10HEX	40HEX / 00HEX	00HEX / 04HEX	08HEX	00HEX / 00HEX	00HEX / 12HEX	00HEX / 01HEX	00HEX / 19HEX	60HEX / B3HEX

MODBUS response of the server¶
Server address	Function code	Server operand address		Number of words		CRC
Server address	Function code	High	Low	High	Low	High	Low
01HEX	10HEX	40HEX	00HEX	00HEX	04HEX	DAHEX	0AHEX

Parameterization \ of the COM_MOD_MAST Function Block inputs¶
EN	COM	SLAVE	FCT	TIMEOUT	ADDR	Number of words = 2 x Number of double words	DATA
FALSE -> TRUE	1	1	16	Application- specific	16384	4	ADR (adwWriteDWord[0])