GPIB bad settings

[hedva92]

When I call X device in the labview, X will respond immediately. When I call X device in the Python,
X device responds to the query_delay argument at the set time. If the query delay turns off, python reports time expired. I think, that instrument under python doesn't able to read a termination from X device. Do not you know how it could be set in Python? Thanks.

import visa
rm = visa.ResourceManager()
x = rm.list_resources()
...
X = rm.open_resource(x[int(n)], query_delay=15 )

[MatthieuDartiailh]

You can set the read and write termination character using the read_termination and write_termination attributes of the object returned by rm.open_resources.

[hedva92]

python returns..
UserWarning: read string doesn't end with termination characters return self.read()

with read_termchar="\n" or "\r" or "\r\n" still waiting for full time of set query_delay

[MatthieuDartiailh]

query_delay is the time the program wait between the write and the read operation when using the query method. I would suggest trying to experiment with different values of query_delay (shorter) and find what minimal value your instrument requires.

[hedva92]

Yes, but 11 s is to much.. when in labview the response is immidietly, maybe 1 s... Its sticking point..

[hedva92]

So what's different?

[MatthieuDartiailh]

If you do not specify a query_delay the command fail is that right ? Could you send the log of the failure along with your script ? You can try to set query delay to 0.01 or 0.1 in which case the delay will be far less noticeable.

[hedva92]

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "xxx\v2.py", line 771, in vykon
    checkOK()
  File "xxx\v2.py", line 55, in checkOK
    if (X.query('SYST:ERR?') == '0,"No error"\n'):
  File "C:\Python\lib\site-packages\pyvisa\resources\messagebased.py", line 569, in query
    return self.read()
  File "C:\Python\lib\site-packages\pyvisa\resources\messagebased.py", line 413, in read
    message = self._read_raw().decode(enco)
  File "C:\Python\lib\site-packages\pyvisa\resources\messagebased.py", line 386, in _read_raw
    chunk, status = self.visalib.read(self.session, size)
  File "C:\Python\lib\site-packages\pyvisa\ctwrapper\functions.py", line 1584, in read
    ret = library.viRead(session, buffer, count, byref(return_count))
  File "C:\Python\lib\site-packages\pyvisa\ctwrapper\highlevel.py", line 188, in _return_handler
    raise errors.VisaIOError(ret_value)
pyvisa.errors.VisaIOError: VI_ERROR_TMO (-1073807339): Timeout expired before operation completed.

with set query_delay=0.1

but when I call common command ddd.. "*IDN?" so device response immediately. The problem is that the calibrator needs more time than setting all the values over a simple "*IDN?"

[MatthieuDartiailh]

Closing since the root problem of the issue what the finite time the instrument needed to handle some particular command. Feel free to reopen if necessary.