Absolute encoder

Hello
I have a question regarding the absolute encoder.
I have to buy a axis system from Bosch and I think with absolute encoder
When this axis is losing the reference (home)?
When someone moves the axis without power?
With power on and encoder cable disconnected?
Should I make a mechanical mark to move the axis at this mark and set again if the reference was lost?
Thank you

one of the advantages of the absolute encoders is that the absolute position of the axis is known by the controller all time
also the homing position is known regarding the presence of the power all time

metwally.mustafa said:

one of the advantages of the absolute encoders is that the absolute position of the axis is known by the controller all time
also the homing position is known regarding the presence of the power all time

Click to expand...

Unless it is a multi-turn digital encoder and the shaft can be rotated with power off.

Assuming a 360 count resolution, the encoder has moved 150 counts clockwise. An Incremental Encoder would have given 150 pulses to be counted by an external device. If you lose power to the encoder at this point and assuming the encoder moved another 60 degrees before it came to a stop, the external device would not know that the shaft position is now 210 degrees. However, if it was an absolute encoder that read shaft position and provided a unique value for this position, it will read 210 degrees upon restoration of power.

Assuming you are looking at the MSK series motor.

With the M2 feedbak code (Optical encoder multiturn absolute EnDat 2.1) you will get 4096 Motor Turns before roll-over of the signal.

Within each revolution, the feedback will have 2048*2^13 resolution or
16,777,216 bits of resolution. The motor project planning manual lists the accuracy at +/- 20 angular seconds.