Homing for NC spindles

Automatic homing

To enable positioning of the spindle, it is necessary to synchronise the coordinate zero point with the signals of the actual value measurement system via a reference marker. In the case of spindles, this can take place during endless rotation without standstill. To this end, the passage of the actual value sensor through zero is used, for example.If no homing has taken place for the spindle, this takes place automatically before positioning with M19 takes place or if positioning or stopping of the spindle with M05 is to take place after the control limit speed has been exceeded.(see Figure 1-9: State graph of the spindle modes for analog drives)

	In the case of digital drive systems (e.g. SERCOS), drive-controlled homing takes place in response to a command (G74). It is not possible to perform automatic homing. This must be deactivated via the axis parameter P-AXIS-00015 (achs_mode).

Programming

G74 S1 or S[G74]

Examples

Homing of spindles and other axes can be started simultaneously but is otherwise not synchronized.

1. Homing of the spindle begins simultaneously with that of the Y axis:

Nxx G74 X2 Y1 S1

2. Same as 1. Without waiting until the spindle has been referenced, the program continues with the next NC block, with the result that the X axis is practically referenced simultaneously:

Nxx G74 S1
Nyy G74 X1 Y2

3. The X and Y axes are referenced first. Spindle referencing then begins:

Nxx G74 X1 Y2
Nyy G74 S1

A detailed description of homing for axes and spindles can be found in the documentation [Homing].