Append crc for modbus

Appends the crc for modbus serial communication

Description

Takes an array to be sent to a modbus device using serial communication and appends two crc bytes for error checking.

• MATLAB release: MATLAB 7.0.1 (R14SP1)

[Stephan Lennartz]

It's not clear whether the CRC algorithm is a very private one or that with a commonly used polynominal factor (see something with CCITT). The receiver has to check the CRC with the same algorithm.
And why computing byte-wise a 16-bit CRC ?
In my experience the offical 8-bit or 16-bit CRC algorithm works best with a 256 byte/word look-up table.

[Brian Keats]

The algorithim is right out of the modbus specification www.modbus.org/docs/Modbus_over_serial_line_V1.pdf I only posted it here to save someone else from having to do it themselves. As for the table lookup option, I couldn't find one for the particular version of crc used in the modbus protocol.

[kamal kannan]

I want matlab tool mother

Regards
s.kamalakannan .

[elif vural]

nothing

[mohamed sa]

very good

[Andriy Nych]

Thank you. You really saved me some time.

[Bruce Cabral]

i have tried gfdeconv(data,polynomial,2)
but it gives wrong results
your code saved me

[Jorge Higuera]

this algorithm use the polinomy X16+X14+1. For others users can change this polynomial for other, for example the CRC CCITT = 1021