
preliminary
preliminary
iC-PVS
LINEAR/OFF-AXIS
BATTERY-BUFFERED ABSOLUTE POSITION HALL SENSOR
Rev A2, Page 17/51
BASIC OPERATION AND SIGNAL DEFINITIONS
The iC-PVS uses an array of hall sensors to detect the
local variation of the magnetic field emerging from a
linear or rotary magnetic target. The target could for
example be a magnetic tape with periodic varying po-
larity and a period pitch (NS spacing) between 1 up
to 5 mm. Different supported magnetic disc scanning
arrangements are shown in Figures 6 to 8
Figure 6: Typical arrangement of iC-PVS scanning
a linear magnetic tape
Figure 7: Typical arrangement of iC-PVS scanning
a radial code disc
360°e
Figure 8: Typical arrangement of iC-PVS scanning
a 32 period axial code disc, 360
°
e marked
When used with a back-bias magnet iC-PVS can scan
ferrous gear wheels with a gear tooth module of 0.3 up
to 1.5. An example for gear wheel scanning is shown
in Figure 9.
From the periodic magnetic field delivered by the tar-
get, the hall sensor array generates internal sensor
signals which are then further processed and passed
to the analog output, as shown in Figure 10. These
analogue sensor signals can then be used as an input
to a downstream interpolator device for high resolu-
tion sine-to-digital conversion and signal processing.
Additionally, a fast and highly efficient internal ADC con-
verts the analog signals and feeds them to the internal
absolute data engine for period counting.
The flux density shows a sinusoidal curve while target
is moved over one magnetic period. The maximum flux
density (B
max
- Elec. Char. 103) is the amplitude of this
sine curve (B
amp
- Elec. Char. 105) plus the presence of
a constant offset (B
dc
) which may be induced by a back-
-bias permanent magnet in gear wheel applications. For
magnetic code discs, the B
dc
offset is zero.
Figure 9: Typical arrangement of iC-PVS scanning
a gear wheel with a back-bias magnet
S
B
moving magnetic target
x
S
N
N
1.0 to 5.0mm
360°e
V (
j
)
sin
V
(
j
)
cos
Figure 10: Signal generation and analog data output