Siemens SINUMERIK 840D sl Function Manual page 117

DB31, ... DBX102.6 (position measuring system 2 activated) == 1
Note
Switching over to a parked position measuring system takes longer than to a non-parked
position measuring system. Because of the time taken, we recommend switching over while
the axes are stationary.
Position of the position measuring system
Absolute position measuring systems
For absolute position measuring systems, the position after deactivating "park" corresponds
to the actual absolute encoder position.
The position measuring system is referenced:
DB31, ... DBX60.4 (referenced/synchronized, position measuring system 1) == 1
or
DB31, ... DBX60.5 (referenced/synchronized, position measuring system 2) == 1
Incremental position measuring systems
For incremental position measuring systems, the position after deactivating "park" always
corresponds to the last deactivation position of the position measuring system.
Switching over to the parked position measuring system is only realized if the parameterized
permissible deviation between the actual values of the two position measuring systems (see
MD36500 $MA_ENC_CHANGE_TOL) is not exceeded. Otherwise, users must apply the "Park
a machine axis" function, in which case such a check is not made.
The position measuring system is not referenced:
DB31, ... DBX60.4 (referenced/synchronized, position measuring system 1) == 0
or
DB31, ... DBX60.5 (referenced/synchronized, position measuring system 2) == 0
Incremental position measuring systems with position transfer
Alternatively, for incremental position measuring systems, when the "Park passive position
measuring system" is active (MD31046 $MA_ENC_PASSIVE_PARKING[<n>] = 1) it is
possible, after deactivating "Park" to transfer the position, and where relevant, also the
"Referenced" status, from the previously active position measuring system.
For every position measuring system of a machine axis, this function can be activated using
machine data:
MD34210 $MA_ENC_REFP_STATE[<n>]
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
A3: Axis Monitoring, Protection Zones
3.2 Axis monitoring functions
117