Product specifications

R01AN0168ED0101 Rev. 01.01 44
Application Note
Chapter 7 Performing Zero Point Detection
required. So, we choose GZF to be 14 (factor
1
/
512
), and we are running
a little bit faster.
2. Having four Measurement Cycles in the measurement window
– We select to use a GCS delay of 1, and a filter depth GFD of 3.
This yields an amount of 4 prescaled clocks of ZPD for each
Measurement Cycle.
–For
GZF, the settings will be the same as above.
(2) Further Strategy Recommendations for the ZPD Measurements
1. The more depth (GFD) the digital filter has, the more flexibility in its
adjustment is given.
2. Several Measurement Cycles are accumulating during the measurement
phase, where
ZMTn is set. This means, if at least one Measurement Cycle
is indicating that ZP was
not reached, this becomes valid for the whole
measurement phase.
3. When adjusting the digital filter, it is recommendable to start off with a filter
setting of
GFL=0 (level of 1).
– Use this setting when the ZP is reached (motor hits the mechanical
stop).
– Adjust the reference level such, that it is one step below of the level,
where the ZP would be recognized.
– Now the ZP is no longer recognized. Increase the filter level, until it is
recognized again.
– This approach can be performed for several settings for the amount of
Measurement Cycles. Then, choose the most reliable setting.
4. When setting up the ZPD table, be sure that the table always contains one
or more full rotations
of the motor. The table restarts continously from the
beginning, if a ZPD measurement does not yield the ZP detection, or if no
measurement is contained at all.
5. If the ZPD motor movement is creating too much jitter, it is possible to
activate the
ZPD Vibration Damping feature of ISM (ZSSn). If activated,
the open end of the measured coil (measure input) will be short-cut with
the other end of the coil, if this is connected to a power or ground side via
Direct I/O Control, after the first setting of ZIPn during a measurement
phase (
ZMTn set).
This short-cut works like an additional breaking or damping, because now,
after the measurement can be aborted (ZP not found), the measured coil
induces and kills the remaining movement energy of the anchor.