modbus_reply_exception man page

modbus_reply_exception — send an exception reponse

Synopsis

*int modbus_reply_exception(modbus_t *ctx, const uint8_t *req, unsigned int exception_code);

Description

The modbus_reply_exception() function shall send an exception response based on the exception_code in argument.

The libmodbus provides the following exception codes:

· MODBUS_EXCEPTION_ILLEGAL_FUNCTION (1)

· MODBUS_EXCEPTION_ILLEGAL_DATA_ADDRESS (2)

· MODBUS_EXCEPTION_ILLEGAL_DATA_VALUE (3)

· MODBUS_EXCEPTION_SLAVE_OR_SERVER_FAILURE (4)

· MODBUS_EXCEPTION_ACKNOWLEDGE (5)

· MODBUS_EXCEPTION_SLAVE_OR_SERVER_BUSY (6)

· MODBUS_EXCEPTION_NEGATIVE_ACKNOWLEDGE (7)

· MODBUS_EXCEPTION_MEMORY_PARITY (8)

· MODBUS_EXCEPTION_NOT_DEFINED (9)

· MODBUS_EXCEPTION_GATEWAY_PATH (10)

· MODBUS_EXCEPTION_GATEWAY_TARGET (11)

The initial request req is required to build a valid response.

Return Value

The modbus_reply_exception() function shall return the length of the response sent if successful. Otherwise it shall return -1 and set errno.

Errors

EINVAL

The exception code is invalid

See Also

modbus_reply(3) libmodbus(7)

Authors

The libmodbus documentation was written by Stéphane Raimbault <stephane.raimbault@gmail.com[1]>

Notes

1.

stephane.raimbault@gmail.com

mailto:stephane.raimbault@gmail.com

Referenced By

libmodbus(7), modbus_reply(3).

04/02/2014 libmodbus 3.0.6 Libmodbus Manual