PIC Microcontroller to Labview

[sam_bachiochi]

Hello,

I am Samarth and i am working on a Pulse Oximeter for my project. I am supposed to display all the samples, MAX & MIN values on Labview as a graph. I had no knowledge of whatsoever on serial communications at the beginning but i managed to do the following, one step at a time.I did the following:

1) Communicate between two computers; sending of ASCII characters from hyperterminal to hyperterminal.
2) Got the PIC Microcontroller to talk to the PC; implmented the code in my program and the PIC16F877 was able to send ASCII characters to hyperterminal
3) Got Labview and Hyperterminal to commnunicate; was able to send and receive ASCII characters on hypterterminal and labview.

Now, here is the big question? how do i go about sending the samples to Labview and so that i can view the samples as a graph in Labview? Please help me out with this.

I did the following, set up all the hardware, started sending the information and could view the transmission on the oscilloscope. The main problem is that i cannot get it to display as a graph on Labview. Below are the steps taken in Labview:

- Started Labview 7.1 and picked 'New" under the menu.
- Chose 'Instrument I/O' and then picked the 'Read and Display VI template: GPIB, Serial...
-Then, at the block diagram, i clicked on the Instrument I/O Assistant, selected the instrument.
- Selected the next step, which was to query and parse. Sent the 'Identification command, *IDN? and got the following error when i run the step.

Error Code: Timeout expired before operation completed
VISA status code=bfff0015

Please guide me from here so that i can view the graph. I have been working on this for some days trying to figure it out and have been losing alot of hair and sleep over this. Please help, your help will be very much appreciated.
Thank You

Best regds,

Samarth

[LoganS]

It's been my experience that when trying to query the a device's information in serial mode, that it's better to break up the *IDN? query into a single write, and two reads. The first read returns the number of bytes to read, and the second actually returns the data that you are looking for. Regardless of whether or not this works, I would recommend breaking up the query simply to be able to tell whether your problem is occuring at the write or reads. Please let me know if this helps!

Logan S.

[LoganS]

Also, check out the Discussion Forum post below:

How to read and display a signal from my PIC Microcontroller onto Labview

It looks like this customer is using the same PIC controller as you and was having a very similar issue.

Logan S.