Siemens 611-D, 840C 10.4.4.3 Program-controlled reference point approach

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*

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).

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

SINUMERIK 840C (IA)