Note:
Experiment with those settings to improve the system linearity. Typically, the system has a more
linear behavior for smaller grid sizes.
3.2.11
Minimum Z Level
Minimum Z level tuning is similar to the Sensing Area step which was intended to adjust the XY
positioning; the Z positioning step is intended to adjust the Z position calculation. The Z position is
adjusted through two steps: minimum and maximum Z level. The first step is to adjust the minimum Z
distance level (Z = 0) by configuring the
Z POS MIN
parameter. This parameter can be modified by using
the respective slider. For fine tuning, click on the
slider
and use the arrow keys on the PC keyboard.
•
Touch the surface of the sensing area with a typical hand posture for the application and keep the
touch.
•
Adjust the slider
Z POS MIN
until the green Z level illustrated in the 3D-signal plot hits the
zero
level
. In this manner, the
zero level
is the lowest level which is possible to reach in the 3D-signal
plot.
•
The Z position must increase while the hand is moving up from the surface.
3.2.12
Maximum Z Level
The second step of the Z level adjustment is to identify the maximum Z distance level. This parameter
setting can be modified by using the respective slider. For fine tuning, click on the
slider
and use the
arrow keys on the PC keyboard.
The sub-steps within the Maximum Distance Level step are as follows:
•
Set
Z POS MAX
to its maximum value.
•
Touch the surface and then slowly remove the hand in Z direction with a hand posture that is typical
for the application.
•
The Z position will stop following the user's hand at some point.
•
Adjust
Z POS MAX
such that the top of the grid is aligned with the green Z level.
3.2.13
Jitter Reduction
Jitter control is configured in the Filter Adjustment window. The filter adjustments are used to reduce the
system jitter (position error when hand is stable) and to define the desired hand tracking speed.
3.2.13.1 Jitter Reduction
Place the hand on the corner, close to the electrodes (where the jitter is more visible), hold it for a few
seconds and watch the position using the Position Tracking window. The position should not have high
deviation in a distance.
Increase the Jitter Reduction parameter value to reduce system jitter. High values will lead to a more
lethargic system behavior and will also slow down the tracking speed. Low values will lead to a more
responsive system behavior and will speed up the tracking speed.
3.2.13.2 Speed
Perform hand gestures to check the tracking speed in the Position Tracking window. Adjust the Speed
parameter value to speed up or to slow down the tracking speed.
MGC3140
Tuning
©
2018 Microchip Technology Inc.
User Guide
DS40002055A-page 20
