Siemens SIMATIC FM 453 Manual page 219

When crossing the RPS, a signal length of ∆t
sured!
The following table shows you the exact location of the synchronization
point on the current-sourcing pattern zero or zero pulse external.
Current-sourcing pattern zero
Zero pulse external (NIX)
Using a Reversing If it is possible for the axis to be "behind" the reference point switch when
Switch
you start reference point approach, a reversing switch can be installed at the
end of the axis in the approach direction, in order to reverse the axis in the
direction of the reference point switch.
On axis movements with referencing feed, a signal length of ∆t
cycle must be assured for the reversing switch!
Example
The value for the reference-point shift (MD27) is traveled after the synchro-
nization point is reached.
Without
The following table describes how a reference can be recorded without a ref-
Reference-Point
erence-point switch.
Switch (RPS)
R+, R–
or Start
FM 453 Servo Drive / Step Drive Positioning Module
C79000-G7076-C453-01
Synchronization Point
Encoder Selection in MD37
Axis position Approach direction from
MD18
RPS
Reference point
Recording of syn-
chronization
1. Instantaneous position is defined as reference point (refer-
ence-point coordinate).
2. Value for reference-point shift is traveled.
Description of Functions
2 FM cycle must be as-
Applicable for Type (0 – 3) of the Reference
Point Approach per MD18
V
R
RPS
V
R
NIX
RPS
Center
Reversing Emer-
switch gency limit
switch
Sequence of movements
2 FM
9-19