To come right to the point, it happens because the SUS400 is magnetic material. Please change it into non-magnetic material.

 

The tip of the MP-981 contains magnetism. The MP-981 detects the difference of the magnetism which is generated by the magnetic circuit between the unit and crests and troughs of the gear tooth. Therefore, when the ferromagnetic material is used for mounting the MP-981, the magnetism between the gear tooth become weak and the sensitivity will tend to be reduced. Generally, iron material is used as the fixing jig for the MP-981, but when several units of the MP-981 are used, the adjustment might be necessary to shorten the gap due to the magnetic affect.

 

The followings are the note on using the MP-981. For further information, please refer to the operation manual.

 

1. Use the ferromagnetic material for the detection gear Module: 1 to 3 or less, gear tooth width: 3 mm or more

2. Use the non magnetic material for the fixing jig of the MP-981 and securely fixed against the vibration.

3. Fix the MP-981 against to the gear teeth to fit to the positioning mark.

4. When mount the several units of MP-981, it is necessary to take a gap of 35 mm or more.

5. The detection error may occur by affection of unstableness of the magnetic circuit in the AC magnetic field (when there is magnetic change). *When the use of large AC motor, mount the unit to the place where is hardly affected by the magnetic field.

6. Not suitable for the detection of precision position. (In the bump detection, the relations between the bump position and signal are uneven.)