Siemens SINUMERIK 840D Function Manual page 54

G2: Velocities, setpoint / actual value systems, closed-loop control
2.4 Setpoint/actual-value system
MD30242
Encoder is independent
System
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$MA_ENC_IS_INDEPENDENT[ n, axis ]
Value Meaning
0 The encoder is not independent.
1 The encoder is independent.
If the actual-value corrections, which are made for the encoder selected for the
position control, are not to influence the actual value of the second encoder
defined in the same axis, then this should be declared as independent.
Actual value corrections are:
● - Modulo treatment
● - Reference point approach
● - Measuring system alignment
● - PRESET
Example: One axis, two encoders, the 2nd encoder is independent
MD30200 $MA_NUM_ENCS[ AX1 ] = 2
MD30242 $MA_ENC_IS_INDEPENDENT[ 0, AX1 ] = 0
MD30242 $MA_ENC_IS_INDEPENDENT[ 1, AX1 ] = 1
Selection, position measuring system 1 / 2: DB31.DBX1.5 / 1.6
If encoder 1 is selected for closed-loop position control, then the actual value
corrections are only performed on this encoder, as encoder 2 is independent.
If encoder 2 is selected for position control, then the actual value corrections are
performed on both encoders, as encoder 1 is not independent.
This means that the machine data only has an effect on the passive encoder of
a machine axis.
2 The passive encoder is dependent.
The actual encoder value is changed by the active encoder. In combination with
MD35102 $MA_REFP_SYNC_ENCS = 1, for reference point approach, the pas‐
sive encoder is aligned to the active encoder - but is NOT referenced.
In the referencing mode MD34200 $MA_ENC_REFP_MODE = 3 (distance-co‐
ded reference marks) the passive encoder is automatically referenced with the
next traversing motion after passing the zero mark distance. This is done inde‐
pendent of the actual operating mode setting.
3 The encoder is independent.
For modulo rotary axes, modulo actual value corrections are also performed in
the passive encoder.
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA