Blocks MODBUS RTU

Back to Libraries

MODBUS_RTU_CFG

Set bus parameters

in	Bus	string		path to bus device (/dev/ttyS0)
in	Baud	int		standard baudrates from 150 to 115200
in	Parity	string[1]		"N" = none, "E" = even, "O" = odd
in	Databit	USINT		Databits (5,6,7,8)
in	Stopbit	USINT		Stopbits (1,2)
out	ERR	bool		indicates some error occurs (0 = OK)
out	ERR_ID	WORD		identifies occured error by unique code

Note:
/dev/ttyS3 = BUS1 on the Connector E
/dev/ttyS2 = BUS2 on the Connector E
Example:

MODBUS_RTU_R_COIL

Reads one coil register

Asynchronous interface
in	Bus	string		path to bus device (/dev/ttyS0)
in	UnitID	byte		device bus address (0-247)
in	OfsAdr	word		register address (1-9999)
in	Timeout	byte		timeout in seconds
out	Q	bool		readed value

MODBUS_RTU_R_DISCRETE

Read one discrete discrete input register

Asynchronous interface
in	Bus	string		path to bus device (/dev/ttyS0)
in	UnitID	byte		device bus address (0-247)
in	OfsAdr	word		register address (1-9999)
in	Timeout	byte		timeout in seconds
out	Q	bool		readed value

MODBUS_RTU_R_HOLDING

Reads one holding register

Asynchronous interface
in	Bus	string		path to bus device (/dev/ttyS0)
in	UnitID	byte		device bus address (0-247)
in	OfsAdr	word		register address (1-9999)
in	Timeout	byte		timeout in seconds
out	Q	word		readed value

MODBUS_RTU_R_INPUT

Reads one input register

Asynchronous interface
in	Bus	string		path to bus device (/dev/ttyS0)
in	UnitID	byte		device bus address (0-247)
in	OfsAdr	word		register address (1-9999)
in	Timeout	byte		timeout in seconds
out	Q	word		readed value

MODBUS_RTU_W_COIL

Writes value to one coil register

Asynchronous interface
in	Bus	string		path to bus device (/dev/ttyS0)
in	UnitID	byte		device bus address (0-247)
in	OfsAdr	word		register address (1-9999)
in	Timeout	byte		timeout in seconds
in	VAL	bool		value to write

MODBUS_RTU_W_HOLDING

Writes value to one holding register

Asynchronous interface
in	Bus	string		path to bus device (/dev/ttyS0)
in	UnitID	byte		device bus address (0-247)
in	OfsAdr	word		register address (1-9999)
in	Timeout	byte		timeout in seconds
in	VAL	word		value to write