Siemens SINUMERIK 840C - Manual (Page 728)

10 Axis and Spindle Installation 12.93
10.4.4 Reference point approach
10.4.4.2 Reference point approach with automatic direction
recognition
Prerequisites
• MD 560* Bit 6 = 1
• Feed enables set
• Reference point cam extends as far as the traversing limit
• Reference point is ahead of reference point cam
The purpose of automatic direction recognition is to eliminate the problems caused by
reference point approach without automatic direction recognition in situations such as those
presented in case 3.
1st case: Axis is ahead of the reference point cam
Axis is ahead of reference point cam
a
EMERGENCY STOP
Reference point
MD 284*
MD 296*
2000 units
Speed
Path
Reference point cam
Reference point pulse
b
c
Traversing limit
When the direction key is pressed, the axis approaches the reference point in the
specified direction (MD 564* bit 0) at the speed defined in MC 296*.
a
Upon reaching the reference point cam, the axis is decelerated to zero speed with the
"Deceleration" signal.
b
The axis then moves away from the reference point cam at reverse speed (MD 284*)
and the next reference pulse is evaluated (refer to Section REFERENCE POINT
APPROACH WITHOUT AUTOMATIC DIRECTION RECOGNITION for a detailed
description of the remaining part of the sequence).
c
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SINUMERIK 840C (IA)