Siemens SINAMICS S120 Function Manual page 259

The software limit switch monitoring is inactive during the complete reference point
approach; only the maximum traversing range is checked. The SW limit switch
monitoring is, if required, re-activated after completion.
The selected velocity override is effective only while searching for the reference
cam (stop 1). This means that the positions "end of cam" and "zero mark" are al-
ways passed with the same velocity. If signal run times (propagation times) occur
for the switching operations, then it is guaranteed that the offset that occurs when
determining the position is the same at every referencing operation.
Axes that only have one zero mark over their complete traversing or modulo range
are designated with parameter p2607 = 0 (no reference cam present). For these
axes, after referencing has been started, a start is immediately made to synchro-
nize to the reference zero mark (refer to step 2).
Reference point approach, step 1: Travel to the reference cam
If there is no reference cam (p2607 = 0), go to step 2.
When starting referencing, the drive accelerates, with the maximum acceleration
(p2572) to the reference cam approach velocity (p2605). The approach direction is
defined using the signal of the binector input p2604 (reference point approach,
start direction).
When the reference cam is reached, this is communicated to the drive using the
signal at binector input p2612 (reference cam); the drive then brakes down to
standstill with the maximum deceleration (p2573).
If, during the reference point approach, a signal is detected at binector input p2613
(reversing cam, minus) or at binector input p2614 (reversing cam, plus), then the
search direction is reversed. The reversing cams are low active. If both reversing
cams are active (p2613 = "0" and p2614 = "0"), then the drive remains stationary
(zero speed). As soon as the reference cam is found, then synchronization to the
reference zero mark is immediately started (refer to step 2).
If the axis moves from the starting position towards the reference cam, a distance
defined in parameter p2606 (max. distance to the reference cam) without the refer-
ence cam being reached, the drive comes to a standstill and fault F07458 (refer-
ence cam not found) is output.
If the axis is already located at the cam, when referencing is started, then travers-
ing to the reference cam is not executed, but synchronization to the reference zero
mark is immediately started (refer to step 2).
© Siemens AG 2006 All Rights Reserved
SINAMICS S120 Function Manual, 03/2006 Edition
Extended Functions
Function module "basic positioner"
4-259