FAQ

What is easy-phi?

easy-phi is a new, open-source and low cost standard for scientific instrumentation.

Why easy-phi?

We want to find simple solutions for physicists. Hence the term "easy". Then the Greek letter phi stands for physics in general. The logo shows schematically a transition with jitter.

Why a new standard?

Because most existing standards are proprietary or expensive (or both). A simple AND gate for your measurement may require a full PXI platform at the moment.

Isn't it a bit too ambitious?

Yes, it is ambitious! But we are motivated to work hard on it and count on the contributions of the community. easy-phi is also your standard.

Why only USB 2.0 on the back-plane? And not a high-speed acquisition standard?

Of course USB 2.0 is too slow for most acquisition systems. But high-speed links (such as PCI-express) age badly, and having a high speed link for all modules, even if not required, increases the costs significantly. On easy-phi, if a module requires high-speed acquisition, the connection is on the front panel (allowing any type of link, such as USB 3.0, PCI-express cable, Ethernet, ...). The back-plane is used for configuration and acquisition of data to be displayed (typical rate: 2 or 5 Hz.

Why QMA connectors for high-speed signals between modules?

QMA has performances of SMA without the need to screw in the connectors. QMA is a standard that isn't that widely used, which avoids mixing of different signal types.

Is 50W (12V, 4A) enough for one module?

The power consumption of the modules has to be limited in order to be able to evacuate the heat. A rack with 12 modules could dissipate 600W in total! For this reason the big rack should be well ventilated. For even higher power, eg for temperature controllers, it is possible to put a power driver outside the rack. The control signal can use a single BNC cable between the rack and the driver. Obviously the driver has its own power supply.

Why modules of 5E (25mm) width?

On the front panel of the modules, there is never a switch, a knob or a display. There are only connectors which are usually mounted directly on the PCB, and LEDs through LED pipes. The width of 5E is well suited and aesthetic! Of course, in some cases, it is possible to double or even triple the width of the module.

Why allowing proprietary modules with an open source standard?

We would like anyone to be able to comply with the standard. Otherwise, a company that already sells a proprietary instrument would not be motivated to adapt its product to easy-phi.