How to read written string

[S_TituS_G]

Hello everybody,
I have a Problem with a VI to communicate with a Sensor via RS 232.
If I try to send the command string via windows hyper terminal eveything works. I get the right
answer strings back and the sensor works. If I try to communicate to the sensor via labviw it seems
that the sensor doesn´t get the string like I send it because it gives me an error String back which means
the command wasn´t right. Now I want to see what exactly LABVIEW sends to the Sensor - but I do not have
a Serial Wire to connect my PC to another to check. So if anybody knows how I can check this in another
way this would be great.

Richard

[TroyK]

Try this loop back test...http://digital.ni.com/public.nsf/allkb/E22DA85E97818DE78625678C0069BFC9#L

There are some other helpful debugging suggestions in that link too. I would check the termination character settings first.

If you don't have any other way to short pin 2 to 3, you can gently push an IDC jumper on across them. Loopback test should then work.
I don't think this will help though, it is really just for checking the hardware and that is rarely the problem. I'm guessing you want to send it in LabVIEW and read it in Hyper terminal? If you had 2 ports you could send it out one in LabVIEW and receive it in the other with Hyper Terminal. But you mentioned you don't have a cable, so I guess that isn't an option. If you did have the cable you would probably find out it was the termination character anyway.

Message Edited by Troy Kujawski on 05-29-2007 11:32 AM

[mikeporter]

First of all to see what LV is sending out the serial port, all you have to do is out a probe on the string going to the Serial (or VISA) write. Next, if Hyper Terminal is working and LV isn't, make sure all the setup parameters are set the same. In addition, if the sensor requires a command terminator, make sure the LV version is using the right one. The default line terminator for the Windows version of LV is a line-feed, whereas many instruments that utilize a command terminator use a carriage-return - as does Hyper Terminal...

You can be assured that the problem is with your LV code.

Mike...

[S_TituS_G]

Hallo everybody and thanks for the quick answers.

Today I checked LV with Free Serial Port Monitor. It shows that the Sensor is getting the right String.

Now I don´t know where to look else. I checked all the things you said - but maybee I´m blind because
of searching too long for the failure.

Well here is all I have about the Sensor Interface






And here an Example Command with answer:



I wrote a short Test VI which I attach here - so maybee somone find something. 🙂

Thanks
Richard

Message Edited by S_TituS_G on 05-29-2007 03:16 AM

[mikeporter]

Are yu sure you are talking ot the right port?

Mike...

[S_TituS_G]

Yes I´m Sure it´s the right Port. I get right answers in Hyperterminal and Error Message-Strings from the Sensor in Labview.
Wouldn´t be so if I speak to the wrong Port.

Cu, Richard

[Dennis_Knutson]

One thing to try is to send a termination character with the command. The VISA Configure Serial Port Termination Character Enable is only for receiving. Look at the shipping examples. The basic one sets the string control to '\' Codes Display and uses the \n. The advanced example uses a VISA property node to set the write termination character.

[S_TituS_G]

"One thing to try is to send a termination character with the command. The VISA Configure Serial Port Termination Character Enable is only for receiving. Look at the shipping examples. The basic one sets the string control to '\' Codes Display and uses the \n. The advanced example uses a VISA property node to set the write termination character."
The Termination Character is "." and is send with every Command String. In Hyper Terminal is everthing set that no additional character is send with the string.
And it works. In LAbview the Same settings and I send the Point at the and of the CommandString like I do with Hyper Terminal - but it doesn´t work.

Richard

[Dennis_Knutson]

In hyperterminal, you are also sending a CR and LF when you hit the enter key.

I don't know what the 'Free Serial Port Monitor' is. I use a utility called portmon. That works well for comparing what hyperterminal is sending with what LabVIEW is sending.

[S_TituS_G]

"In hyperterminal, you are also sending a CR and LF when you hit the enter key.

I don't know what the 'Free Serial Port Monitor' is. I use a utility called portmon. That works well for comparing what hyperterminal is sending with what LabVIEW is sending."

I  don´t hit enter key. 🙂 But I will try that tool and will post the new Results.
Thanks so far.
Richard