Siemens SINUMERIK 840D Function Manual page 771

The following functions are possible only with a synchronized spindle:
● Thread cutting
● Tapping without compensating chuck
● Axis programming
For further information about synchronizing the spindle, see Section "R1: Referencing
(Page 291)".
Why reference?
In order to ensure that the controller detects the exact machine zero when it is switched on, the
controller must be synchronized with the position measurement system of the rotary axis. This
process is known as referencing. The sequence of operations required to reference an axis is
known as search for reference.
Only a referenced axis can approach a programmed position accurately on the machine.
For further information about referencing the rotary axis, see Section "R1: Referencing
(Page 291)".
Installation position of the position measurement system
The position measurement systems can be installed as follows:
● directly at the motor in combination with a contactless proximity switch on the spindle as a
zero mark encoder
● at the motor using a measuring gearbox in combination with a contactless proximity switch
on the spindle as a zero mark encoder
● Directly on the spindle
● on the spindle via a measuring gearbox in combination with a contactless proximity switch
on the spindle as a zero mark encoder (only with ratios not equal to 1:1)
Where two position measuring systems are provided, they can be installed either in the same
location or separately.
Synchronization procedure
When the spindle is switched on, it can be synchronized as follows:
● The spindle is started with a spindle speed (S value) and a spindle rotation (M3 or M4) and
synchronized with the next zero mark of the position measurement system or with the next
signal from the contactless proximity switch.
● The spindle is to be positioned from standstill using SPOS, M19 or SPOSA. The spindle
synchronizes with the next zero mark of the position measurement system or with the next
proximity switch signal. It is then positioned to the programmed position.
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA
S1: Spindles
18.3 Reference / synchronize
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