Siemens SINUMERIK 840C - Manual (Page 947)

12 Functional Descriptions 10.94
12.18.14 Special cases of gearbox interpolation
Flowchart for PLC-controlled reference point approach
Activate control
Activate GI grouping 1
Selection ref. point mode
Initiate reference point approach with leading axis X1 (following axis X follows X1)
Reference point reached?
Deactivate GI grouping 1
Activate GI grouping 2
Initiate reference point approach with leading axis X (following axis X1 follows X)
Reference point reached?
Enable following axis overlay
Initiate on-the-fly synchronization for grouping 2
Synchronization reached (following axis)
Disable following axis overlay
Selection "Automatic" mode
END
Note
It is advisable to deactivate the synchro monitors in the PLC program until the gantry axis
reference point approach process is complete.
The ”Set reference dimension via PLC request” function is available with SW 4 and higher.
• 2 measuring systems for each gantry axis
In order to carry out the referencing process when the gantry is unstressed, you can install 2
different measuring systems at the same time for each gantry axis, i.e. an (indirect) SIPOS
absolute system as the 1st measuring system and an incremental (direct) measuring system
as the second.
After power on, the SIPOS systems - as the 1st measuring system - transmit their absolute
values to the control. It must be ensured that the NC MD "Absolute offset valid" (1803*.3) is
set. The absolute positions of the two gantry axes are therefore available to the control. GI
grouping 1 is then linked in (leading axis X1, following axis X). Any dimensional offset between
the two axes is eliminated with the absolute values during the subsequent "on-the-fly
synchronization" process. The incremental, direct system is then activated for referencing
purposes. During referencing, NC MD "Absolute offset valid" (1808*.3) must be reset
(referencing is not otherwise possible). The procedure subsequently applied for reference point
approach is the same as if only incremental measuring systems were in use. Finally, any
existing small dimensional offset can again be eliminated by means of another "on-the-fly
synchronization".
Note:
Please refer to functional description of the SIPOS absolute encoder for further information.
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SINUMERIK 840C (IA)