Absolute encoders with SSI/EnDat and PROFIBUS DP at the top, and
DRIVE?CLiQ and PROFINET IO at the bottom

Absolute encoders (absolute shaft encoders) are designed on the same scanning principle as incremental encoders, but have a greater number of tracks. For example, if there are 13 tracks, then 2¹³ = 8192 steps are coded in the case of single?turn encoders. The code used is a one?step code (gray code) which prevents any scanning errors from occurring.

After switching on the machine, the position value is transferred immediately to the controller. There is no need for homing.

DRIVE?CLiQ, SSI and EnDat absolute encoders are of advantage in time?critical applications.

In plants with a large number of encoders, encoders with PROFIBUS DP or PROFINET IO are more advantageous due to the reduced wiring overhead. PROFIBUS DP encoders are programmable and support isochronous mode with direct data exchange. The encoders with PROFINET IO are also parameterizable, additionally have two ports and support the RT and IRT operating modes.

Single?turn encoders

Single?turn encoders divide one revolution (360?degrees mechanical) into a specific number of steps, e.g. 8192. A unique code word is assigned to each position. After 360 degrees the position values are repeated.

Multi?turn encoders

Multi?turn encoders also record the number of revolutions, in addition to the absolute position within one revolution. To do this, further code discs which are coupled via gear steps with the encoder shaft are scanned. When evaluating 12 additional tracks, this means that 2¹² = 4096 revolutions can be coded.