Piezo-valve controller for the gas inlet system of the fusion experiment Wendelstein 7-X

► Shown in this paper are the requirements and the specification of a Piezo valve controller for the fast gas inlet system of fusion experiment Wendelstein 7-X. ► It gives an overview about the gas inlet system and of the valve controller for control of the 10 piezo gas valve for the fast gas inlet. ► The paper contains descriptions of the operational states and the design of the analogue part of the valve controller unit. The gas inlet system of the fusion experiment Wendelstein 7-X (W7-X) comprises eleven gas inlets around the torus for controlled provision with working gases in the torus. This fast gas inlet system is designed for different operating modes of W7-X, from short discharges with only a few seconds durations to steady state plasma operation with operation time of 30min. Piezo valves of type FGIS (FGIS: Fast Gas Injection System from General Atomics) are used as actuators for the W7-X gas inlet system. The design of an intelligent control unit for the FGIS Piezo valves are introduced and discussed. The integration of the valve controller units into the W7-X control component “W7-X gas inlet” and their planned application in an experiment run is described.