Getting no data from VISA TCP/IP query

[sswager]

Hello all, I am trying to remotely control an SRS IGC100 using VISA and TCP/IP protocol.  When I try to query the instrument for data using VISA read and VISA write I get no errors but no data either.  Previously I had issues with the read function timing out but I used VISA Bytes At Port Propery Node under the Serial Pallete which seemed to clear that error up.  

[Dennis_Knutson]

You are using a function that is returning 0 bytes and 0 bytes are being read so obviously you have no errors or data. Why you would want to read the serial port when you are using an Ethernet connection?

Have you communicated to the instrument in MAX? Is it in fact listed in MAX as a TCP/IP resource? I would recomend you start with some basic commands such as *IDN?. Try different termination characters (i.e. CR and LF).

You should also download the driver and try it. You might have to make some modifications because it's listed as serial but at least it uses VISA.

[sswager]

I have communicated with the instrument in MAX and it is set up as a TCP/IP resource.  I also have downloaded the driver but the actions it can perform are not sufficient enough for what I need to do.  As far as using the serial port property node for Ethernet connection that was a silly mistake.  Should I just set the number of bytes to be read to something like 1000 or does this cause VISA read to timeout because it is looking to recieve that many bytes but recieves significantly less?  Also in VIs in the driver when sending commands it appears termination characters are not used.

[Dennis_Knutson]

Since the VISA interactive control has the \r and \n characters as default, try removing them in MAX and see if communication fails. You will then know that you have to add one or the other in your LabVIEW code.

There are differences in how vendors implement TCP/IP communication. The ones I've use work just like a GPIB instrument and you can safely request a high byte count.