Reference Direction - Siemens SIMATIC S5 Manual

Machine Data and their Structure
This machine data contains the position of the reference point in the current coordinate system.
This coordinate can be assigned to the current position in the "set reference point" mode or can
be assigned to a point on the axis determined by a precontact, the reference direction and type
of reference point approach in the "reference point approach" mode (see Section 2.5.4.5 "Refer-
ence Direction").
2.5.4.5

Reference Direction

The reference direction specifies whether the reference point is to be approached in a forward
direction ("0"; for a rotary axis, in a clockwise direction), or in a reverse direction ("1"; for a rotary
axis, anti-clockwise) If the axis is not exactly on the precontact at the beginning of the reference
point approach, the axis first travels in the opposite direction to the specified reference direction,
as far as the reverse point and then in the reference direction until the reference point is detected
4.2.3.1 "Reference Point Approach").
Note
I
The reference point can only be reproduced when it is always determined in the
same direction.
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