Device and Vendor Specific Modbus Functions

Custom Function Codes
int	customFunction (int slaveAddr, int functionCode, void *requestData, size_t requestLen, void *responseData, size_t *responseLenPtr)
	User Defined Function CodeThis method can be used to implement User Defined Function Codes. More...

Advantec ADAM 5000/6000 Series Commands
int	adamSendReceiveAsciiCmd (const char *const commandSz, char *responseSz)
	Send/Receive ADAM 5000/6000 ASCII command. More...

Detailed Description

Some device specific or vendor specific functions and enhancements are supported.

Function Documentation

customFunction()

int customFunction	(	int	slaveAddr,
		int	functionCode,
		void *	requestData,
		size_t	requestLen,
		void *	responseData,
		size_t *	responseLenPtr
	)

User Defined Function CodeThis method can be used to implement User Defined Function Codes.

The caller has only to pass the user data to this function. The assembly of the Modbus frame (the so called ADU) including checksums, slave address and function code and subsequentially the transmission, is taken care of by this method.

The modbus specification reserves function codes 65-72 and 100-110 for user defined functions.

Note

Modbus functions usually have an implied response length and therefore the number of bytes expected to be received is known at the time when sending the request. In case of a custom Modbus function with an open or unknown response length, this function can not be used.

Parameters

slaveAddr	Modbus address of slave device or unit identifier (Range: 1 - 255 for serial, 0 - 255 for TCP)
functionCode	Custom function code to be used for Modbus transaction (1-127)
requestData	Pointer to data sent as request (not including slave address or function code)
requestLen	Length of request data structure (0-252)
responseData	Pointer to data structure which holds response data
responseLenPtr	Length of response data buffer (0-252). This value will be adjusted should the actual response data be less. A FTALK_INSUFFICIENT_BUFFER error code will be returned in case the allocated buffer size was insufficient.

Returns

FTALK_SUCCESS on success or error code. See Error Management for a list of error codes.

References FTALK_ILLEGAL_ARGUMENT_ERROR.

adamSendReceiveAsciiCmd()

int adamSendReceiveAsciiCmd	(	const char *const	commandSz,
		char *	responseSz
	)

Send/Receive ADAM 5000/6000 ASCII command.

Sends an ADAM 5000/6000 ASCII command to the device and receives the reply as ASCII string. (e.g. "$01M" to retrieve the module name)

Parameters

commandSz	Buffer which holds command string. Must not be longer than 255 characters.
responseSz	Buffer which holds response string. Must be a buffer of 256 bytes. A possible trailing CR is removed.

Returns

FTALK_SUCCESS on success or error code. See Error Management for a list of error codes.

Note

No broadcast supported

References FTALK_CONNECTION_WAS_CLOSED, FTALK_ILLEGAL_ARGUMENT_ERROR, FTALK_IO_ERROR, and FTALK_SUCCESS.