Efficient Networks Siemens Sinamics S120 - Manual (Page 264)

Function modules
7.9 Basic positioner
Drive Functions
264
Function Manual, (FH1), 07/2007 Edition, 6SL3097-2AB00-0BP4
Note
In this case the direction of approach to the reference zero mark is the opposite to the axes
with reference cams!
External zero mark present (p0495 ≠ 0), no reference cam (p2607 = 0):
Synchronization to an external zero mark begins as soon as the signal at binector input
p2595 (start homing) is detected. The drive accelerates to the velocity, specified in
parameter p2608 (zero mark approach velocity) in the direction specified by the signal of
binector input p2604 (reference point approach start direction). The drive synchronizes to the
first external zero mark (p0495). The drive continues to travel with the same velocity and
travel is started to the reference point (refer to step 3).
Note
The velocity override is inoperative during this process.
An equivalent zero mark can be set using parameter p0495 (equivalent zero mark input
terminal) and the corresponding digital input selected. As standard, for increasing actual
position values, the 0/1 edge is evaluated and for decreasing position actual values, the 1/0
edge. For the equivalent zero mark, this can be inverted using parameter p0490 (invert
measuring probe or equivalent zero mark).
Search for reference, step 3: Travel to reference point
Travel to the reference point is started when the drive has successfully synchronized to the
reference zero mark (see step 2). Once the reference zero mark has been detected, the
drive accelerates on-the-fly to the reference point approach velocity set in parameter p2611.
The reference point offset (p2600), the distance between the zero mark and reference point,
is extended.
If the axis has reached the reference point, then the position actual value and setpoint are
set to the value specified using connector input p2598 (reference point coordinate) (as
standard, connector input p2598 is connected with setting parameter p2599). The axis is
then homed and the status signal r2684.11 (reference point set) set.
Note
The velocity override is inoperative during this process.
If the braking distance is longer than the reference point offset or a direction reversal is
required as a result of the selected reference point offset, then after detecting the reference
zero mark, the drive initially brakes to standstill and then travels back.
On-the-fly homing
The mode "flying referencing" (also known as post-referencing, positioning monitoring),
which is selected using a "1" signal at binector input p2597 (select referencing type), can be
used in every mode (jogging, traversing block and direct setpoint input for positioning/setting-
up) and is superimposed on the currently active mode. Flying referencing can be selected
both with incremental and absolute measuring systems.