labview driver for vitrek 4700

[idans]

Hi all

i am trying to write driver for Vitrek 4700 HV DMM, this DMM communicate through RS232.

When i send commands from NI max test panel i get respond from DMM but, when i try to

communicate from labview  VI  i get visa read error -1073807339 to *idn queryfor same communication settings 

my question is are any hidden setup in ni max test panel ?

[wiebe@CARYA]

Most likely you need to init visa with enabled end characters.

Hard to say without any code...

It might be that max and LV are opened at the same time.

[idans]

here is my code

[wiebe@CARYA]

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@idans wrote:

here is my code

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It is in fact (just) an image of your code... "ceci n’est pas une vi".

you might have better luck simply sending \n in the string. IIRC, visa uses the end characters for reading, but doesn't automatically attach the end character when sending data. Rational is probably that it doesn't know when you're message is complete. You could use multiple sends to send parts of one message.

I'd use "VISA Configure Serial Port.vi", as it's a bit less verbose...

[idans]

I attached my vi after adding configure serial port and a /n char after *idn, but no good

[wiebe@CARYA]

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@idans wrote:

I attached my vi after adding configure serial port and a /n char after *idn, but no good

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There's no "/n" after "*IDN?" in that VI. And it should be "\n". And that will only work if the string is set to '\' code display mode. If not (normal display mode), simply add an enter.

[idans]

my typo \n after idn?

[wiebe@CARYA]

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@idans wrote:

my typo \n after idn?

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You programmed the Serial port to use \r as an end character. Carriage Return (\r) should be Line Feed (\n). Probably, I didn't read the manual.

\r could be correct, but then you should also send \r. I think it should be \n though.

[idans]

ok i got some advancment ' i added a for loop around *idn? query and i let run twice, at first iteration i get read error but in second loop i get a respons from instrument. 

could someone explain me what is the problem? because i give the read vi long timeout ,5sec, but only at second attempt i get response  

[wiebe@CARYA]

I'd remove the buffer flushing and changing the buffer size. This might be lagging (taking some time), spoiling the first send. I've never needed those.

A wait between the flushing\init and the send might fix the problem, but I'd avoid waits.

In general, I'd use the serial init VI.