help with sentorr pressure gauge via rs232-usb adapter

[MaxXx]

Hello everyone,

I am fairly new to LabView so please excuse my lack of knowledge and trivial questions. I have a senTorr pressure gauge by varian ( http://www.varianinc.com/cgi-bin/nav?products/vacuum/measure/controllers/st/index&cid=KKJLOQHQFM ) and I'm trying to get LabView to work with it (read pressure measurements). I do not have any RS-232 port on the computer so I have to use a USB to serial rs-232 adapter to connect it. I have installed the proper drivers for the adapter and it was assigned as COM3, however I still can not see the port in LabView MAX, or instrument I/O > Serial. I also tried using hyperterminal but nothing showed up. How can I get Labview to read data from the port?

Thanks.

[RavensFan]

Do you see the port in Windows device manager?  How do you know it was assigned Com3?

If it shows up in Windows device manager, it should show up in MAX unless you have some issue with your LabVIEW and device drivers installation.  What version of LabVIEW and MAX do you have?  Can you post a screenshot showing the serial ports in MAX?

What do you mean by you don't see the port in Instrument I/O> Serial?  As in the palette in LabVIEW?  If you drop a VISA function on your block diagram and create a constant for your VISA resource (upper left terminal on connector) what shows up in the drop down list of that constant?

If you are having problems having something show up in Hyperterminal, you will need to get that figured out before you get things working in LabVIEW.  Are you able to open Com3 in Hyperterminal?  What commands do you have to send to the device to get a response?  Does the device have an instruction manual listing the commands?  Do you have parity and baud rate set to match the device?

[MaxXx]

Hello,

Yes I see it in windows device manager, that's how I know it's COM3. The port does shows up in hyperterminal, it's just there's no response when connection is initiated. 

I have labview 8.5.1 and MAX 4.4.1f0

I dontunderstand what you meant by "create a constant for your VISA resource". The manuals for the sentorr can be found on the website posted earlier and I have already set all the correct parity, bits, etc..

Message Edited by oioi on 09-05-2008 03:55 PM

Message Edited by oioi on 09-05-2008 03:57 PM

[Dennis_Knutson]

Obviously the port shows up in MAX because that is what the image shows. If communication does not happen in either Hyperterminal/MAX/LabVIEW, then you have a problem with the com settings or you are using the incorrect cable. There are two types of cable - null-modem and straight-through. Check your manual for correct type and also double-check the com settings. Until you get communications working in Hyperterminal, you will be just wasting your time in LabVIEW.

[MaxXx]

The Sentorr manual says the default configuration is for null modem mode and I just found out the rs-232/db9 cable I have is wired straight through. So I guess I'll have to get another adapter/cable then. Will this one work? http://www.cablestogo.com/product.asp?cat_id=106&sku=08075  .The current RS-232 cable is M-F and the USB adapter is M-USB.

Thank you for all the helps.

Message Edited by oioi on 09-05-2008 04:35 PM

Message Edited by oioi on 09-05-2008 04:36 PM

[RavensFan]

That adapter should work as it is null modem.  And if you already have a cable of the right genders on each end that connects from the device to the PC, then this should just be able to slip in at one of the connections as it is male to female.

Here is a picture of a constant for a VISA resource.  As you can see, Com1, Com3, and LPT1 are all present on my system and are recognized by LabVIEW.

You can also create this by placing a VISA resource control on the front panel from the I/O palette.  Then, if you want a constant, right click on the terminal on the block diagram and select Change to Constant.

PS:  As a tip, when inserting a web address into a message, please use the button at the top of the editor that looks like a chain link.  This will allow your web link to be able to be clicked on to go directly to that address rather than forcing the reader to open a new browser window and doing a cut and paste operation to open that link.  Here are your 2 addresses entered as links.

http://www.varianinc.com/cgi-bin/nav?products/vacuum/measure/controllers/st/index&cid=KKJLOQHQFM

http://www.cablestogo.com/product.asp?cat_id=106&sku=08075

By the way, I had looked at the first link when you originally posted it.  But I was unable to find any manuals on it like you said.  Nothing with any real technical information.  It looked more like a web page of a sales brochure.

Message Edited by Ravens Fan on 09-05-2008 11:49 PM

[MaxXx]

I got the adapter today and plugged it in but it still doesnt work. Hyperterminal still doesnt get any response/reading/commands from the sentorr and the instrument did not show up in labview's instrument I/O assistant. I have checked all the settings as stated in the manual (baud settings, channel, etc) and still no go. Any idea why it's not communicating?

Here's the link to the manual  http://www.varianinc.com/image/vimage/docs/products/vacuum/manuals/measure/shared/sentorrcontrol.pdf

Thanks

[Dennis_Knutson]

Since it still doesn't work in Hyperterminal, it might be time to try and troubleshoot the problem with the vendor. You still might have the wrong cable and the instrument could be set up incorrectly (i.e. RS485 instead of RS232).

p.s. You will not see an instrument in MAX or the Instrument I/O Assistant. All that you will ever see is a com port. It does no good to try LabVIEW until you get Hyperterminal to work correctly.

[RavensFan]

Take a look at the DIP switch settings on pages C-1 and C-4 of the setting.  Are they set for null modem or standard?  What kind of cable are you using, null modem or straight through?  Try using the other kind of cable.  Try setting the DIP switches to the other setting.  I think you have a mismatch between your cable type and your DIP switch settings.

I don't know what you mean by "instrument did not show up in labview's instrument I/O assistant".  It is a serial device using the com port.  Only a Com port will show up in I/O assistant.  Are you expecting an instrument name?  That only applies if it was a GPIB device.

[MaxXx]

I have attached a diagram of the cable/adapter connections used in the setup. I have tried switching the null adapter in position 1 and 2 but it still doesnt work. Also I do not have an RS232 port on the computer so that's why I need to use the RS232 to USB adapter.

The graduate student that I work with said that he is pretty sure that the sentorr has an RS232 card but I will open it up and check this along with the switch once I get permission from my professor.