High precision magnetic analyzer is one of key points in technologies of Chinese space solar telescope, which is under pre-investigation. Magnetic analyzer needs a modulation component to change its polarization state. For ground-based use, usually electroptics crystal KD*P is a good option. However KD*P needs a power supply as high as thousands volts.

In space environment, such a high pressure source is hardly available. Therefore we have to use an alternative, an optomechical modulator. In the modulator, the related optical components rotate precisely to realize modulation. This raises a crucial request for position accuracy and positioning times of optical components rotation.

This paper describes our developing process of the electric control for the magnetic analyzer. Firstly, hardware facilities, control software design and test results as well are given. Then, some problems in manufacture and adjustment are analyzed and discussed. After overall optical, mechanical and electric tests, it shows that the accuracy of rotation position of the optical components is better than 10’’(p-p)(checking with a precise 24 sides’ standard); while time for rotating 90 degrees is less than 2 seconds. The results demonstrate that the magnetic analyzer has met the design requirements.