write_raw stalls forever

[pipatron]

While trying to talk to my FY6600 connected to an USB serial port over pyvisa proxy, my code hangs completely on instr.write_raw(…).

import pyvisa
rm = pyvisa.ResourceManager("<server>:5000@proxy")
instr = rm.open_resource("ASRL/dev/ttyUSB0::INSTR",baud_rate=115200,write_termination='\n',read_termination='\n')

mode = 0

if mode == 0:
    instr.query("UMO")    # Works
if mode == 1:
    instr.write("UMO")   # Also works
    instr.read()
if mode == 2:
    instr.raw_write(b"UMO\n")  # Stalls here, no timeout
    instr.read()

The same code works locally on the proxy server where the instrument is connected.

[casabre]

@pipatron thanks for raising this issue and sorry for the late reply. Was quite busy at my day job.

Frankly spoken, I don't know why it is not working. The server forwards any output or exception of the real VISA handle to the client. Thus, I would expect that, if the VISA timeout was set, this timeout applies and the VISA handle should raise an exception which will be forwarded to the client.

Unfortunately, I don't have any real USB VISA device. Thus, I cannot test. Can you maybe support and debug the server?

[pipatron]

@casabre Sure, thanks for the response. I'll see if I can collect some more information about it. I just wanted to hear that it is supposed to work, so I don't spend time chasing ghosts that aren't even implemented!