RS-232 Communication ?

[iniesta]

In this VI ( please take a look at the attached file ) i do a loop back test with the COM1 port, if i reduce the delay-before-read time to less than 15 ms ( this value can be different in your computer i think ), the program can not work properly any more.

delay >= 15ms

delay < 15 ms

So what is the problem here ?

Can i do something to solve this problem ?

Thanks in advanced !

[Mellroth]

QUOTE(iniesta @ Jan 25 2008, 01:33 PM)

In this VI ( please take a look at the attached file ) i do a loop back test with the COM1 port, if i reduce the delay-before-read time to less than 15 ms ( this value can be different in your computer i think ), the program can not work properly any more.

You should only update the chart if you really read a value from the serial port, i.e. you should check that you get requested number of bytes at the serial port.

In your case (with a small delay) you probably get "bytes at serial port" = 0, or a value less than than the actual amount transferred.

You then convert a non-complete response into a number, hence the strange trace.

/J

[LAVA 1.0 Content]

I can't open your code because I did not install LV 8.5 Yet. So I can't give you comment on your code. On the other hand, I just want to point it out that you may use event to read your data with the VISA Event function. (Instrument I/O\VISA\VISA Advance\Event Handling, in your function palette).

Hope this can help.