R1: Reference point approach
15.9 Referencing with absolute value encoders
Basic Functions
Function Manual, 09/2011, 6FC5397-0BP40-2BA0
1241
15.9.5
Calibration with BERO
Function
For adjustment using BERO, a reference point approach to a defined machine position is performed the same as
for incremental measuring systems. In this case the BERO replaces the encoder zero mark that the absolute
encoder does not have. After successful completion of reference point approach, the NC automatically calculates
the reference point offset from the difference between the encoder absolute value and the parameterized
reference point value.
Procedure
Proceed as follows for adjustment with BERO:
1. Set referencing mode to "Referencing with BERO":
MD34200 $MA_ENC_REFP_MODE = 2
2. Assign reference point value:
MD34100 $MA_REFP_SET_POS =
Reference point value
3. Start reference point approach.
Reference point approach can be started manually in JOG-REF mode or in AUTOMATIC or MDA mode from
a part program (
G74
).
After a successful reference point approach, the absolute encoder is calibrated, the actual value system of the
machine axis is synchronized, and the machine axis is referenced.
To identify this, the NC sets an interface signal for the measuring system that is currently active:
DB31, ... DBB60.4 / 60.5 (referenced/synchronized 1 / 2) = 1
Signal propagation delay compensation
The signal propagation time can cause corruption of the absolute position detected by the NC. The signal
propagation time can be compensated for in any direction:
MD31122 $MA_BERO_DELAY_TIME_PLUS (BERO delay time plus)
MD31123 $MA_BERO_DELAY_TIME_MINUS (BERO delay time minus)
Note
If the BERO is removed after adjustment of the absolute encoder, the referencing mode
must be assigned to "Referencing with absolute encoder".
MD34200 $MA_ENC_REFP_MODE = 0
Note
Prerequisite for a correct compensation of signal propagation time is drives of type
SIMODRIVE 611 digital. The compensation times are pre-set in delivery condition in such a
way that changes are usually not required.
