LabView OBD

[decdeery]

hi all,

i am currently in the process of writng an emissions estimation model whereby i intake engine speed and load and use these parameters interrogate engine emission maps. i had envisaged using labview to automate the process but am having difficulties establishing communication with the vehicle's On-Board Diagnostic System using  using the VISA vi's. I have established communication using hyperterminal but i am getting an error message when i try to use the VISA read and write VI's to establish communication. i have attaches a screenshot of the error message and would be extremely grateful if there was anybody who could help me with my problem

thanks,
Declan

[AnalogKid2DigitalMan]

Is the serial port currently open and in use by another application (i.e. Hyperterminal)? That may be one possible explanation.

[decdeery]

cheers for the reply,

you were right about hyperterminal being open. however, when i tried to establish communication again i was getting another error message. i have attached this message and would be once again grateful if anybody could make sense of it for me

declan

[AnalogKid2DigitalMan]

Would you be able to attach your vi so we can have a look at it?

What version of LabVIEW and VISA are you using?

[decdeery]

i've attached a copy of the vi i'm using. i'm using labview version 8.0 at the moment. i'm relatively new to it all but i am slowly getting into it

[AnalogKid2DigitalMan]

I had a hard time following your code, but I think you need to add a VISA Configure Serial Port function prior to doing any read or write operations. To illustrate, open Help and search for examples containing Serial. The Configure will set up baud rate, data bits, parity etc that must match the setting of the device you are trying to communicate with.

Hope it helps.