Manual – IPOSplus®
63
6
Referencing
Position Detection and Positioning
Set a maximum of half the value of the calculated preset value. If P955 is ≥ 32, only enter
a quarter of the calculated preset value. Start an IPOS
plus®
program with a positioning
operation between two valid points at moderate speed. Reduce or increase parameter
P910 "Gain X controller" step-by-step until the best movement and positioning charac-
teristics have been set. If P955 is set to a high value, it may be necessary that values in
P910 are < 1.
The position value provided by the absolute encoder is available in variable H509 (ACT-
POS.ABS). The position value can be processed with the internal IPOS
plus®
control
even without direct positioning.
6.6 Referencing
For applications using absolute positioning commands, you must define the reference
point (machine zero). Depending on the encoder type, this setting must either be made
at initial startup (absolute encoder) or each time the machine is switched on again (all
other encoders).
MOVIDRIVE
®
supports 9 types of reference travel that can be set via P903 Reference
travel type, P904 Reference travel to zero pulse and the arguments of the IPOS
plus®
command _Go0 ( ... ); or GO0 ... and that result from the reasonable combination
of the following characteristics:
• Encoder is set without reference travel (no reference travel)
• Search direction is set (= direction of movement at start of reference travel)
• Referencing is set to the hardware limit switches
• Referencing is set to zero impulse (only possible in external encoders when the
resolution < 5000 inc./revolution)
• Referencing is set to reference cam
If referencing is set to the hardware limit switches and/or the reference cam, these must
be set as binary inputs.
Parameter P941 Source actual position is used to define which encoder is used for ref-
erence travel.
Once the drive is enabled, reference travel is started using one of the following methods:
• Via a positive edge on binary input P600 ... P606 or P610 ... P617 that is set to the
function REF.-FAHRT START
• via the IPOS
plus®
command _Go0 ( ... ); or GO0 ...
The display changes to "c" - REFERENCE MODE.
Stop ramp P136 is always used for acceleration during the reference travel. Reference
travel types with reference cam or limit switch, accelerate to P901 reference speed 1
and then search for the condition for the end of the reference travel with P902 reference
speed 2. Reference type 0, uses P902 Reference speed 2 right away.
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