A magnet current monitor for gyrotron magnet power supplies

Gyrotrons are widely used in Electron-Cyclotron Heating systems (ECH) to heat electrons in plasmas. Modern gyrotrons require a precise magnetic field for proper operation which is supplied by an electromagnet with multiple windings. The current for the electromagnet is provided by multiple high-current power supplies. The loss of any one of the power supplies during operation can cause significant and expensive damage to the gyrotron. An independent power supply monitoring system can prevent damage should a magnet power supply fail. This paper presents a magnet current monitor system capable of measuring and monitoring five magnet currents simultaneously. It provides limit tests, an interlock output for power supply failures and a status display for the operator. A self-test feature is included and the measurements and status can be examined through an Ethernet connection. The rapid advance of inexpensive microcontroller technology has led to the development of small microcontroller platforms and associated code libraries that have dramatically decreased the costs and development time required for such projects. This paper describes the use of a popular open-source software, open-hardware platform for the design and fabrication of the magnet current monitor.