Automatic Referencing - Siemens SINUMERIK 840D Function Manual

Note
SMExx Sensor Modules
Automatic referencing or restoration of the actual position to the last buffered position after
restarting the control is only possible in conjunction with SMExx (externally mounted) Sensor
Modules. When using SMCxx (cabinet) or SMIxx (integrated) Sensor Modules, the actual
position cannot be restored after restarting the control (power on). The measuring system of the
machine axis must be referenced again.
10.10.2

Automatic referencing

Function
During automatic referencing, the actual position of the active measuring system of the
machine axis is set to the last buffered position and "referenced" set as encoder state after
switching on the control. This makes it possible to start programs in the AUTOMATIC and MDI
modes directly after run-up of the control.
Requirements
● The active measuring systems when the control is switched on must already have been
referenced once before switching off.
● At the time the control is switched off, the machine axis must be at standstill with "Exact stop
fine" (DB31, ... DBX60.7 == 1) are located.
Note
If the machine axis is not at standstill with "Exact stop fine" when switching off, the actual
position will be initialized with " 0" when switching on. "Not referenced" is displayed as the
encoder state.
Parameterization
The automatic referencing is enabled by setting the encoder state to "Automatic referencing is
enabled, but the encoder has not been referenced":
MD34210 $MA_ENC_REFP_STATE[<encoder>] = 1
After the measuring system has been referenced, the encoder state displays that automatic
referencing will be executed the next time the encoder is activated:
MD34210 $MA_ENC_REFP_STATE[<encoder>] == 2
NC/PLC interface signals
After automatic referencing, the encoder state "Referenced" is displayed for the active
measuring system:
DB31, ... DBX60.4/.5 == 1 (referenced/synchronized 1/2)
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA
10.10 Automatic restoration of the machine reference
R1: Referencing
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