VISA serial read timeout error

[jd4moto]

I am using a CBcom thermocouple serial mod connected to one of compact fieldpoints RS-232 ports. Using the serial read and write VI, I can write and read a value with no problem...but after about 5 minutes I get a timeout error...any thoughts? (I have varied the timeout time, the termination char is correct, and I have increased the byte count, all to no avail.)

Thanks,
John Davis

[LA 75]

Hello John,

Are you trying to access the serial port of your FieldPoint controller from LabVIEW? If so, this is not possible. The serial ports on these controllers are only accessible to embedded VIs running on the controller. The development and transfer of embedded VIs to FP/cFP controllers must be done with LabVIEW RT.

Please let me know if you were trying to communicate to your controller from a host computer or you were actually embedding your VI in the controller to see if we need further troubleshooting.

Thanks,

LA

[jd4moto]

I am running my application on the cFP RT engine, and am able to read a value for a limited amount of time. I have included both of my serial communication VI's so maybe you can see an obvious error. Also, should I connect the return count output from VISA write to the byte count input on VISA read? Thanks for you time, John Davis

On another note...I am using global variables to pass my information from VI's and I read that this method adds jitter and uses more memory...Is there another way to do this (see attached VI) thanks!

[Ricardo_SR]

Hi ,

There is nothing that could point to an error in your VI. Have you tried setting the VI as target but not embedded in the RT module and see if you get any error from a specific VI or function. What could be happening is that there might be occurring an error but we might not be seeing it.
Are you running an embedded application or just a target VI? What versions of driver and LabVIEW RT do you have?

Ricardo S.

[Ricardo_SR]

Hello,

I was checking and apparently you cannot run the serial ports on the FP when target to it, only when you are embedded. What I would recommend to you is run the part of the serial communication without the FP module. Meaning directly with a PC or laptop just to check if your VI or code is ok.

Ricardo S.
National Instruments.

[nguyenhk]

HI
I am using a Pulnix TM1040 and a frame grabber PCI-1422 of NI. Now, when grabbing, it showed a dialog:"IMAQ error: the serial read didnot complete within the specified timeout period". I have downloaded the camera file from NI but the sesults were the same.
Does anyone know about this problem, please help me. I need to fix this as soon as possible for my experiment because now I am running out of time.
If you can, reply one more to my email: nguyenhk@aero.pauir.itb.ac.id
Thank you very much.

[David S.]

Hi nguyenhk 

Please see my reply to your post in the appropriate thread: http://forums.ni.com/ni/board/message?board.id=200&message.id=9759#M9759