VISA runtime

In order to use GPIB, USBTMC, TCPIP or PXI, you need to install a VISA runtime. This runtime consists of a VISA library (typically visa32.dll or visa64.dll) that handles the communication with your instruments.

Vendors

There exist different vendors that have their own VISA runtimes, e.g.

• National Instruments VISA runtime: https://www.ni.com/de-de/support/downloads/drivers/download.ni-visa.html#409839
• Keysight IO Libraries Suite (Keysight VISA) https://www.keysight.com/en/pd-1985909/io-libraries-suite?nid=-33330.977662.00&cc=DE&lc=ger&cmpid=zzfindiosuite
• Tektronix TEKVISA CONNECTIVITY SOFTWARE https://de.tek.com/oscilloscope/tds7054-software/tekvisa-connectivity-software-v411
• Rohde&Schwarz RSvisa https://www.rohde-schwarz.com/de/applikationen/r-s-visa-application-note_56280-148812.html

If additional hardware is used, e.g. GPIB adapters, additional drivers must be installed and it is recommended to stay with one vendor.

• Tektronix/Keithley KUSB and KPCI manual: https://de.tek.com/keithley-accessories/test-fixtures-manual/models-kpci-488lpa-and-kusb-488b-reference-manual

Still, it is also possible to install the runtimes of two vendors side-by-side, e.g. as described here.

Troubleshooting

• To check whether SweepMe! was able to find a runtime, open the menu 'Tools' -> 'Port Manager'. If there is no error message, everything is alright.
• The VISA library must have the same 'bitness' as SweepMe!: SweepMe! 1.5.8 uses Python 3.9 (64 bit) and SweepMe! 1.6 uses Python 3.14 (64 bit), so you need the 64-bit VISA library. Older SweepMe! versions (Python 3.6, 32 bit) needed the 32-bit library.
• SweepMe! first tries the default VISA library of your system and then a few standard installation paths of the Keysight and Rohde & Schwarz runtimes. If the VISA library has not been found, but you are sure that the right file is installed, you can change the path that is used to load the runtime (see below).
• Try to use Python and pyvisa directly to see whether it is possible to load the correct VISA library: Link

Individual runtime path

SweepMe! loads the VISA library during the program start. If your VISA library is not found, you can add an individual path. As SweepMe! relies on the library pyvisa, you can use the following link that describes how to create a configuration file '.pyvisarc' where the path to the VISA runtime is given. An example .pyvisarc can be downloaded from the Download section of a SweepMe! account.