Communication with BOC Edwards Active Gauge Controller

[cbreaux6]

I had a VI that I was previously using to communicate with an RQCM. It would send the machine commands in hexadecimal and would spit out frequency data properly with no complaints. So I figured when I wanted to start collecting pressure data from my Active Gauge Controller (AGC) I could just alter/tweek the RQCM Labview to make it record the pressure data. After stripping the Labview down to the bare minimum in which I use a Visa Read/Write/Close combo after entering my command in the front panel, I still can't seem to get the pressure measurements.

The AGC has two modes. Printer mode in which it automatically sends data to me at a continuous rate and Control Mode, in which I can give the AGC a query or command. Whenever I put it in Printer Mode the data starts spitting out, but it's completely jumbled and in no order. When I go to Control Mode and try to ask the AGC for specific data, it just ignores all of my commands. From what I can tell from the AGC Manual about communicating, all I should have to do is type in "?CD 6 CR" and it should give me the pressure display of gauge 6, but it gives me nothing. I saw one other person had issues with an AGC but from that post I didn't really follow what to do.

Attached is my Labview VI and below is a link to the AGC manual for communicating via RS232 if any were curious. Any help would be appreciated.

Thank you

[cbreaux6]

Manual for RS232 communication with AGC

http://idealvac.com/files/brochures/Edwards_AGC_D386-52-880_IssueM.pdf

[nyc_(is_out_of_here)]

Take LabVIEW out of the picture, and use Hyperterminal or something like it.

[cbreaux6]

Not quite the fix I need here. You see I have a solenoid that's being driven by Labview for my experiment, and when it opens is the moment I want to start collecting data. Added, while I'm not very familiar with Labview, I'm even less familiar with the Hyperterminal

[Emily-C]

Hi cbreaux6,

I would also suggest starting with nyc's suggestion. See if you can do basic serial communication with your device directly from Windows to make sure you're sending the right commands. You could try doing this from Hyperterminal, or PuTTY. Try sending "?C 6 CR" from one of these applications and see if you get the right response back. 

If this works, then move to a simple serial communication in LabVIEW. Go to Help > Find Examples, Hardware Input and Output > Serial with some examples to get you started.

I hope this helps!

[cbreaux6]

I've been messing with the Hyper Terminal.... I know for a fact that I'm in the right Com Port, since I've now unplugged every other connecting leading into a Com Port. I also enter the values of "9600, 8 bit, No Parity, 1 Stop bit" (which matches what I have set the AGC to). The only uncertainty I have is with the Flow Control. If I put the flow control to "None" or "Xon/Xoff", I can apply the changes and type in the Hyper Terminal, but nothing happens.

However, if I put the flow control to "hardware" and then click "apply changes" and "ok", I always see a few bits of text on my screen before I even start typing in the terminal. The bits of text are just scrambles of letters and symbols though, as if they don't mean anything. This does make it more difficult to type though since in "Hardware" mode the computer lags sometimes. Still, I type in various commands and press enter and nothing gets sent back to me. 

[Emily-C]

Hi cbreaux6,

It will depend on your device, but in general flow control of None should work. Getting back a scramble of letters and symbols often indicates that the selected baud rate is wrong. How did you go about setting the baud rate on your device?

What commands have you tried sending to your device? It might help to start with something simple you should already know the answer to, like using the BA command to read back the baud rate.

Since you've never communicated with your device before it's good to try getting started directly from Windows, but if you're having trouble with hyperterminal you could try opening a VISA Test Panel for the COM port from MAX. This document has more information on getting started with serial instruments in MAX.

If you're still having trouble communicating from Hyperterminal, you might want to try contacting the manufacturer. They should be able to help you get the right settings for your device. Once you know all the correct settings for serial communication, you should be able to use those same settings to successfully communicate from MAX and LabVIEW.

Thanks!

[cbreaux6]

With the Baud Rate, the AGC has a sub menu in it that can let me select the Baud Rate. I've just been making sure that the Baud rate I set on the AGC matches that of the one I select when I open the hyperterminal (normally 9600 or 19200)

The commands that I've been sending it are "?CD 6 CR" but I did try "?BA CR" and got nothing back. 

[Emily-C]

Hi cbreaux,

I looked through the manual for sending queries, and it says:

"Each query or command is sent to the AGC via the RS232 serial link as a text message - a

sequence of ASCII coded characters. The first character of the text message is a ! for a command,
or a ? for a query. The next two characters are the mnemonic representation of the particular
query or command, followed by other data if required. The last character must be a carriage
return CR (ASCII char 13)."

Are you typing the letters CR, or in your text is that representing a carriage return (ASCII char 13)?

This is an external document, not provided by NI, but it is specific to your device and has some setup and configuration suggestions that I thought might help you. 

If you're still not able to connect to your device through Hyperterminal, I suggest you try contacting the manufacturer to make sure that you're using the right settings and sending commands with the right syntax.

I hope this helps!