python – pyvisa can not locate a VISA implementation

pyvisa can not locate a VISA implementation and can not load the NI-VISA backend:

>>> import visa
>>> import platform
>>> print (platform.architecture ())
(& # 39; 64bit & # 39 ;, & # 39; WindowsPE & # 39;)
>>> rm = visa.ResourceManager ("C: \ Windows \ System32 \ visa64.dll")
ValueError: A VISA implementation could not be located. Install the NI or pyvisa-py binary.

The configuration of the system:

  • Windows 10 Pro v1709 (64 bits)
  • Python v2.7.15 (64 bits)
  • pyvisa v1.9.1
  • NI 17.50 Visa

I have verified that the .dll files exist:

  • C: Windows System32 visa32.dll
  • C: Windows System32 visa64.dll

and the pyvisa.info reads:

C: Python27> python -m visa info Machine details: Platform ID:
Windows Processor 10-10.0.16299: Intel64 Family 6 Model 60
Step by step 3, GenuineIntel

Python: Implementation: CPython Executable:
C: Python27 python.exe Version: 2.7.15 Compiler:
MSC v.1500 64 bit (AMD64) Bits: 64bit Build:
April 30, 2018 16:30:26 (# v2.7.15: ca079a3ea3) Unicode: UCS2

PyVISA version: 1.9.1
Backends:
neither:
Version: 1.9.1 (included with PyVISA)
Binary library: Not found

But for some reason, pyvisa can not load the NI-VISA back end. The same happens if the backend remains unspecified:

>>> import visa
>>> rm = visa.ResourceManager ()
ValueError: A VISA implementation could not be located. Install the NI or pyvisa-py binary.