Suppress Serial Flush Buffer

[PPLLC]

Is there a way to configure VISA to not send the MJ_FLUSH_BUFFERS command during a serial session?

[PPLLC]

The answer to this part of the problem is found here. It turns out the IOCTL_SERIAL_GET_COMM_STATUS is causing a similar problem. Anybody have any idea how to suppress this status request? It seems this USB to 422 device (or the serial device) is very basic in its function and would be happiest if I simply performed reads and writes without any other functions being performed.

[Burban]

Chris,

I'm not sure how to suppress this request.  Do you mind posting an NI-SPY capture of the error occuring?

If you haven't done an NI-SPY capture before, some instructions are here.

Thanks,

[PPLLC]

Ben,

It will be Thursday before I can do a capture, but I do have more information for you. The device (Intelligent Motion Systems MForce Controller) does not return an error when it receives the IOCTL... command. The device only responds to commands sent one character at a time with no other commands allowed between characters. For example, the software that shipped with the device sends the command 'MR 1000\n' as individual characters, and the device echoes each character back as it is received (telnet style communication over USB). If the same command is sent as a string, the device ignores it. If the characters are sent individually out of LabVIEW/VISA, the IOCTL... command occurs and the command is ignored.

[Burban]

Chris,

Take a look at the attached example.  It's from this thread.  It seemed to solve problems using the same or similar USB to 422 converters.