if you are communication via RS232(485):
there has been a vi for euro. controllers since LV 3.1
that does the the job (or is a good starting point) in the info-labview vi collection.
another is the modbus.llb
here is some info about it:
VI let you communicatie via a serial inerface with Modbus instruments.
PS. No error checking is done in this version; Error clusters only implemented for future use - Users might implement this for their own needs...
This VI is referenced to the Modicon Modbus Protocol as described in the Modicon Modbus Protocol Reference Guide PI-MBUS-300 rev. D
This VI is only tested with a Eurotherm T103 unit controller but should alse work with any other Modbus Instrument.
Maarten van Bree
AIR technical automation,
the Netherlands
[<< email adresses deleted just to prevent the author of the vi from spam>>]
http://www.air.nl
Greetings from Germany
Henrik
LV since v3.1
“ground” is a convenient fantasy
'˙˙˙˙uıɐƃɐ lɐıp puɐ °06 ǝuoɥd ɹnoʎ uɹnʇ ǝsɐǝld 'ʎɹɐuıƃɐɯı sı pǝlɐıp ǝʌɐɥ noʎ ɹǝqɯnu ǝɥʇ'