Control Alicat PC through Labview

[tam_2407]

Hi, I am totally new at LabView VISA. Anyone please show me how to control Alicat pressure controller (PC  series) via LabView. I had reviewed the VI built by Alicat and built one for myself but my computer doesn't seem to speak to the pressure controller, that or the device does not listen. I checked cable (DB9 to 8-pin mini DIN) and COM1 port. What specific drivers do I need? What is register number (they had it in the "sample" VI)? And what is the correct format of buffer to write (I've seen vary forms).

Thanks a lot.  

[NathanT]

Hello Tam,

       Welcome to the NI Discussion Forums!  Here is a link to the LabVIEW Plug and Play Instrument Drivers that you need with installation instructions.   You will probably want to read through this "How to Use and Instrument Driver in LabVIEW"  Tutorial first.  Before using LabVIEW,confirm that you can communicate with your instrument through VISA using Measurement and Automation Explorer (MAX).  You will probably need to consult the instrument's manual to see what specific serial port settings you will need to use.  Only once you have established communication in MAX should you try to communicate with the device with LabVIEW.

       The "register number" should be explained in the device's programming manual and hopefully is taken into account with the LabVIEW Instrument Driver.

Cheers,

NathanT

[tam_2407]

Thanks a lot for your response. I have downloaded the LabVIEW Plug and Play Instrument Driver for Alicat Scientific PC series and had communication with the instrument through VISA, but when I ran the driver, it gave me error in "VISA read", code "1073807339". Could you help me figure this out? I will try to provide as much info as I can.

Thank you very much.

[Dennis_Knutson]

Anytime you deal with a serial connection and have a problem, you should double and triple check the cable and com settings. Instead of the driver, try using Hyperterminal if you can, to test the connection. Problems with using Hyperterminal are easier for the vendor to troubleshoot since they often have never heard of LabVIEW. If they provide some sort of utility program, run that and see if it works.

Not at all sure why you say that you have communication with the instrument in VISA when you get a timeout error. That means that you do not have communication to the instrument through VISA.

[tam_2407]

Oh I see, then maybe I did not have the communication with the instrument. I set the port setting of Window and VISA to the values required (these values are default-set in the instrument). What else could cause the communication problem? I do not have access to Hyperterminal. 

Thank you very much.

[Dennis_Knutson]

As I said, double and triple check the cable and com settings.

Hyperterminal is an optional install on Vista. I believe. Standard on other OS's. I would strongly encourage you to get it installed if you are using Vista for the reason I mentioned. You may need to contact the vendor for help.

[tam_2407]

I tried Hyperterminal to see if I have communication with the device, but I got the error "Unable to connect to COM1" even though I could not detect anything else using that port  at the same time.

[Dennis_Knutson]

Do you have LabVIEW closed when you try to use Hperterminal? That could keep it opne if you were using the driver and did not close the port.

[tam_2407]

I tried again with everthing else but Hyperterminal closed, even disabled and re-enabled the port, but I still had this error message.

[Dennis_Knutson]

Really no idea without having the system here. Check the running services to see if there is anything there.