RS-232 emulation on USB device

[Jimmy2975]

Hi,

This is regarding the Photometer PR-525 from Photoresearch. As mentioned earlier this emulates RS-232 via USB (4-pin regular to 5-pin type B mini USB on the device end). I have been successful communicating on the HYPERTREMINAL, however not using Labview 7.1(NI-visa 3.1). I have followed the same setup as in hyperterminal (baud=2400, data bits=8, parity=none,stop bits=1, flow control = hardware).

This is how it works in HYPERTRMINAL in steps after opening a connection

1. Type PHOTO. As soon as this is done "REMOTE MODE" is displayed on the hyperterminal window. There is no need for any character termination for PHOTO
2. Now type E and then press ENTER. ">" in now displayed on the hyperterminal window.
3. Now the device is ready to take any measurements and displays the data for e.g >M1 command would give back 00000,1,8.743e+02. (this is the actual data that the hyperterminal reads form the device)

I receive a timeout error at the Visa read session. I do not know if I'm able to write not just read or if there is any fundamental error that I'm missing. I have taken care of the carriage return and line feed the ASCII comands need in HYPERterminal. In Labview I terminate using "\r\n".

Any suggestions will be of great help.

As Josh mentioned earlier I did try the Set I/O buffer size before visa write but w/o any success.

[Dennis_Knutson]

Why do you think you're taking care of the termination character? You don't have any default values in the write string control and the control is not set for '\' Codes Display. Unless you do that (right click on the control and select it), what you are sending is the text "\", "r", "\", and "n". The termination character setting for VISA Configure Serial Port is for a read and not a write. You're also setting the baud rate to 2100 and not 2400 and you're not setting the flow control because you've got nothing wired there.