pyvisa.errors.VisaIOError: VI_ERROR_RSRC_NFOUND (-1073807343): Insufficient ... when executing a script, but manually from interpreter works

[nexysm]

I have a very strange issue. When trying to open a resource from the terminal interpreter it works, but it doesn't when the very same code is executed inside the script. Here is the script:

import pyvisa
import time

rm = pyvisa.ResourceManager()
time.sleep(2)
resources = rm.list_resources()
print (resources)
time.sleep(2)
print (resources)
instrument = rm.open_resource('TCPIP::192.168.188.148::INSTR')

The error is following:

/usr/local/lib/python3.7/dist-packages/pyvisa_py/tcpip.py:407: UserWarning: TCPIP:instr resource discovery is limited to the default interface.Install psutil: pip install psutil if you want to scan all interfaces.
  UserWarning,
('TCPIP::192.168.188.148::INSTR',)
('TCPIP::192.168.188.148::INSTR',)
Traceback (most recent call last):
  File "/usr/local/lib/python3.7/dist-packages/pyvisa_py/tcpip.py", line 452, in after_parsing
    self.interface = Vxi11CoreClient(host_address, port, self.open_timeout)
  File "/usr/local/lib/python3.7/dist-packages/pyvisa_py/tcpip.py", line 356, in __init__
    rpc.TCPClient.__init__(self, host, prog, vers, open_timeout)
  File "/usr/local/lib/python3.7/dist-packages/pyvisa_py/protocols/rpc.py", line 821, in __init__
    pmap = TCPPortMapperClient(host, open_timeout)
  File "/usr/local/lib/python3.7/dist-packages/pyvisa_py/protocols/rpc.py", line 801, in __init__
    RawTCPClient.__init__(self, host, PMAP_PROG, PMAP_VERS, PMAP_PORT, open_timeout)
  File "/usr/local/lib/python3.7/dist-packages/pyvisa_py/protocols/rpc.py", line 452, in __init__
    self.connect(1e-3 * open_timeout)
  File "/usr/local/lib/python3.7/dist-packages/pyvisa_py/protocols/rpc.py", line 486, in connect
    raise RPCError("can't connect to server")
pyvisa_py.protocols.rpc.RPCError: can't connect to server

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "short_test.py", line 10, in <module>
    instrument = rm.open_resource('TCPIP::192.168.188.148::INSTR')
  File "/usr/local/lib/python3.7/dist-packages/pyvisa/highlevel.py", line 3284, in open_resource
    res.open(access_mode, open_timeout)
  File "/usr/local/lib/python3.7/dist-packages/pyvisa/resources/resource.py", line 279, in open
    self._resource_name, access_mode, open_timeout
  File "/usr/local/lib/python3.7/dist-packages/pyvisa/highlevel.py", line 3209, in open_bare_resource
    return self.visalib.open(self.session, resource_name, access_mode, open_timeout)
  File "/usr/local/lib/python3.7/dist-packages/pyvisa_py/highlevel.py", line 167, in open
    sess = cls(session, resource_name, parsed, open_timeout)
  File "/usr/local/lib/python3.7/dist-packages/pyvisa_py/tcpip.py", line 85, in __new__
    return newcls(resource_manager_session, resource_name, parsed, open_timeout)
  File "/usr/local/lib/python3.7/dist-packages/pyvisa_py/sessions.py", line 324, in __init__
    self.after_parsing()
  File "/usr/local/lib/python3.7/dist-packages/pyvisa_py/tcpip.py", line 454, in after_parsing
    raise errors.VisaIOError(constants.VI_ERROR_RSRC_NFOUND)
pyvisa.errors.VisaIOError: VI_ERROR_RSRC_NFOUND (-1073807343): Insufficient location information or the requested device or resource is not present in the system.`

[MatthieuDartiailh]

That's weird indeed. Does the same happen if you do not list the resources ?

[MatthieuDartiailh]

I transferred the issue since you use the pyvisa-py backend

[nexysm]

That's weird indeed. Does the same happen if you do not list the resources ?

No, in that case it doesnt happen, and I also increased the delay after listing the resources and runs fine.