Of course, it would be great if someone could develop an implementation for these protocols not relying on Visa. Visa is especially interesting as it enables controlling instruments via USB (for devices compliant with the USB-TMC protocol) or TCP/IP (LXI standard) without the need to develop specific drivers. However, standard synchronous (blocking) operations are allowed too, and the code can safely and transparently handle concurrent use of both synchronous and asynchronous commands.Īs the software has been made sufficiently general to adapt it to various Gpib libraries, it could eventually also be adapted to other interfaces such as the Visa library and the serial port. Asynchronous operations are queued which makes programming very simple. This works quite well as I could easily obtain relatively high reading rates (e.g., an average of 2-3 reading/second/device for 10 devices, i.e., a total of 20-30 operations/second) even in configurations where a few devices are very slow (e.g., 2-3 seconds response time). The solution proposed in this software consists in using as much as possible the asynchronous operations where a different thread for each device is used so that the write/read operation sequences for different devices become automatically interleaved. This project originated from my efforts to obtain efficient GPIB control in an environment where some devices are slow to respond and usually create a bottleneck in the data flow. Download source - 178.5 KB (last updated 23 rd May, 2018, see History).The VISA standard directly in Python (see the PyVISA-Py project for moreĭetails). Most bus systems used by instruments which is why one can envision to implement In addition, Python can be used to directly access Python can be used to call functions from a The VISA specification has explicit bindings to Visual Basic, C, and G Limited to certain interface devices, such as the vendor’s GPIB card. Work together with arbitrary peripherical devices, although they may be Of vendors offer VISA libraries, partly with free download. Today VISA is implemented on all significant operating systems. Instrumentation systems comprising GPIB, VXI, PXI, Serial, Ethernet, and/or VISA is a standard for configuring, programming, and troubleshooting In order to ease this unfortunate situation, the Virtual Instrument SoftwareĪrchitecture (VISA) specification was defined in the middle of the 90ies. To use, you have to find libraries that support both your device and its bus There are manyĭifferent protocols, sent over many different interfaces and bus systems The programming of measurement instruments can be real pain. National Instruments, Agilent, Tektronix, (That’s the whole program really!) It works on Windows, Linux and Mac open_resource ( 'GPIB0::12::INSTR' ) > print ( inst.
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