Siemens SINUMERIK 840Di Function Manual page 1478

Detailed Description
2.6 Referencing with absolute value encoders
Value
FALSE
TRUE
2.6.7 Automatic encoder replacement detection
Functionality
Automatic encoder replacement detection is required for absolute encoders in order to detect
if the encoder has been replaced and therefore needs to be readjusted.
The NC reads the encoder-specific serial number of the encoder from the drive every time
the control is powered up. If the serial number has changed the NC resets the encoder
status to "Encoder not calibrated".
MD34210 $MA_ENC_REFP_STATE = 0
The status of the measuring system is indicated as "Not referenced":
DB31, ... DBB60.4/60.5 (referenced/synchronized 1/2) = 0
Serial number display
The NC stores the serial numbers read during power-up machine axis specifically in:
MD34230 $MA_ENC_SERIAL_NUMBER (encoder serial number)
Note
Currently, only the serial numbers of absolute encoders with an EnDat interface can be read.
For all other encoders the display shows that no serial number has been read.
Automatic encoder replacement detection can therefore only be used with the specified
encoder types.
2-38
Meaning
Traversing is enabled.
When reference point approach is initiated, the machine axis moves to the reference point
position. Reference point approach is completed when the reference point position is
reached.
Traversing is not enabled.
When reference point approach is initiated, the machine axis does not move and
reference point approach is terminated immediately.
Reference Point Approach (R1)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0