Siemens SINUMERIK 840C - Manual (Page 729)

07.97 10 Axis and Spindle Installation
10.4.4 Reference point approach
2nd case: Axis is at the reference point cam
Axis is at reference point cam
Speed
MD 284*
d
EMERGENCY
STOP
Reference point
2000 units
Path
Reference point cam
Reference point pulse
Traversing limit
When the Direction key is pressed, the PLC's "Deceleration" signal enables the NC to
establish with absolute accuracy that the axis is already located at the reference point
cam. The axis therefore accelerates in the reverse direction (MD 564* bit 0) to the speed
defined in MD 284* (refer to Section REFERENCE POINT APPROACH WITHOUT
AUTOMATIC DIRECTION RECOGNITION for a detailed description of the remaining
portion of the sequence).
d
10.4.4.3 Program-controlled reference point approach
Reference point approach can be executed in a part program with G74. When MD 1808*, bit 4,
is set, reference point approach to the coded reference marks is executed automatically. The
direction is defined in MD 564*, bit 0, and not with the direction keys.
Example:
AUTOMATIC or MDA mode
N10 G74 X LF
Note:
From SW 5, simultaneous referencing of up to 5 axes is possible.
Example:
N10 G74 X Y Z U V LF
© Siemens AG 1992 All Rights Reserved 6FC5197- AA50 10–39
SINUMERIK 840C (IA)