6.
Precise homing with encoder INDEX signal
Homing with use of so-called encoder INDEX signal is another argument for servo drives. This type of
homing is very precise even if the HOME switch has large dispersion of the trip point. In practice,
homing with the INDEX allows to eliminate inaccuracy of the HOME switch.
CSMIO/IP-S is STEP/DIR type controller and does not have an encoder input. It does not mean that it
is impossible to base on INDEX. You can use built-in CSMIO/IP-S function or function of synchroniza-
tion HOME signal and INDEX in servo drive.
6.1
Solution no. 1 – Homing on “index” function
In plugin configuration window
there is a possibility to chose hom-
ing mode for each axis, with or
without index.
The configuration was described in
detail in section 10.
The solution has the advantage that
CSMIO/IP controller is able to speci-
fy a distance between home switch-
off activation on and index position
and in situation when the distance
is to small – axis homing will be
stopped. It is very comfortable and safe solution, because if index is close to Homing activation posi-
tion there may be some homing errors with even entire motor rev.
That is why, during function configuration we also give pulses number per rev and CSMIO/IP verifies
whether index is in safe distance (minn15 degrees, or so 1/24 motor revs).
According to the fact that CSMIO/IP-S has no encoder inputs, index signal is connected to standard
digital inputs of the controller. The problem is that the controller requires 24V logic signals. However
many servo drives have index output “open collector” - type and then we can handle it easily.
As it is shown - pull-up resistor is enough. However sometimes we do not have “open collector” –
type output available, then the only way for homing on index is to add external, simply electronic
system:
Do wejścia cyfrowego C
S-
MIO/IP-S
C S - L a b s . c . – C S M I O / I P - S - C N C C o n t r o l l e r
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