Function modules
8.8 Basic positioner
Drive functions
522 Function Manual, 11/2017, 6SL3097-4AB00-0BP5
Step 2: Synchronization to the reference zero mark
(encoder zero mark or external zero mark)
Reference cam available (p2607 = 1):
In step 2, the drive accelerates to the velocity specified in p2608 (zero mark approach
velocity) in the direction opposite to that specified using binector input p2604 (reference point
approach start direction). The zero mark is expected at distance p2609 (max. distance to
zero mark). The search for the zero mark is active (status bit r2684.0 = "1" (reference point
approach active)) as soon as the drive leaves the cam (p2612 = "0") and is within the
tolerance band for evaluation (p2609 - p2610). If the position of the zero mark is known
(encoder evaluation), the actual position of the drive can be synchronized using the zero
mark. The drive starts the search for reference (refer to step 3). The distance moved
between the end of the cam and the zero mark is displayed in diagnostics parameter r2680
(difference between the cam - zero mark).
● Encoder zero mark available (p0494 = 0 or p0495 = 0)
1)
, no reference cams (p2607 = 0):
Synchronization to the reference zero mark begins as soon as the signal at binector input
p2595 (start referencing) 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 zero mark and then starts to travel towards the
reference point (refer to step 3).
Note
In this case the direction of approach to the reference zero mark is the opposite to the
ax
es with reference cams!
● External zero mark available (p0494 ≠ 0 or p0495 ≠ 0)
1)
, no reference cams (p2607 = 0):
Synchronization to an external zero mark begins as soon as the signal at binector input
p2595 (start referencing) 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 (p0494 or p0495)
1)
. 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 and the corresponding di
gital input selected using
parameters p0494 or p0495
1)
(equivalent zero mark input terminal). As standard, for
increasing actual position values, the 0/1 edge is evaluated and for decreasing actual
position values, the 1/0 edge. For the equivalent zero ma
rk, this can be inverted using
parameter p0490 (invert measuring probe or equivalent zero mark).
1)
Observe the explanation provided in Chapter "Function diagrams and parameters
(Page 527)".
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