R1: Reference point approach
15.5 Referencing with incremental measurement systems
Basic Functions
1220 Function Manual, 09/2011, 6FC5397-0BP40-2BA0
Functional sequence
Two different cases apply for automatic referencing, which depend on the encoder status:
• Case 1: Encoder status = 2
Automatic referencing in parameterized, the measuring system has been referenced and the machine axis
was switched off in status "exact stop fine".
As a result:
- The actual value system of the machine axis is synchronized with the buffered actual value.
- The status of the machine axis is set to "Referenced".
DB31, ... DBX60.4 / 60.5 (Referenced/Synchronized 1/2) = 1
• Case 2: Encoder status = 1
Automatic referencing in parameterized but the measuring system has either not yet been referenced or the
machine axis was not switched off in status "exact stop fine".
As a result:
- The actual value system of the machine axis is synchronized with zero.
- The status of the machine axis is set to "Not referenced":
DB31, ... DBX60.4 / 60.5 (Referenced/Synchronized 1/2) = 0
15.5.6.2 Position restoration with POWER ON
Function
In addition to the axis position, incremental encoder buffering also sets the referenced status. However, the
restored incremental encoder position is actually not the same as "real" re-referencing. In order to assess the
quality of the restored position, a "restored" status is delivered instead of the "referenced" status.
Parameter assignment
In order to restore the last axis position buffered before switching off, the encoder status must be set to the value
"3":
MD34210 $MA_ENC_REFP_STATE = 3
Referencing does not take place automatically. The encoder state is "Position restored". Monitoring for the
software limit switches is already activated in this state.
This state is indicated by the following signals in the NCK PLC interface:
DB31, ... DBX71.4 ("restored 1") for encoder 1
DB31, ... DBX71.5 ("restored 2") for encoder 2
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