The instrumentation of a powder x‐ray diffractometer for automatic data acquisition and control of experiments is described. The present system configuration is set up to step‐scan preselected intervals in the 2&thgr; range, in preset stepping increments, while operating either in the fixed time or in the fixed count mode. The data can either be stored in punched paper tape and cards, or be transmitted to a computer. At the end of a complete 2&thgr;‐scan, one or more experimental parameters can automatically be changed, after which the whole scan is started again.