KMA199 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.
Product data sheet Rev. 2 — 7 December 2011 15 of 36
NXP Semiconductors
KMA199
Programmable angle sensor
The deviation from the value at room temperature
tempRT
describes the temperature
drift of the angle, compared to the value, which the sensor provides at room temperature:
(3)
with:
T
RT
: room temperature (25 C)
12.6 Angular error
The angular error
ang
is the error of angle difference measured by the sensor, if the
mechanical angle deviates from
0
to
1
. Here
0
and
1
are arbitrary angles within the
angular range. The angle measurement at
0
is the initially programmed reference angle,
programmed by the customer at room temperature and zero hour upon production. The
angle measurement at
1
is made at any temperature within the ambient temperature
range:
(4)
with:
0
,
1
: arbitrary mechanical angles within the angular range
meas
(
0
, T
RT
): programmed angle at
0
, T
RT
=25C and zero hour upon production
meas
(
1
, T
amb
): angle measured by the sensor at
1
and any temperature within T
amb
This error comprises non-linearity and temperature drift related to the room temperature.
Figure 11 shows the envelope curve for the magnitude of angular error |
ang
| versus
1
for all angles
0
and all temperatures T
amb
within the ambient temperature range. |
ang
|
has its minimum, if
1
is in the range of 1 around
0
. Here only the microlinearity error
lin
and the temperature drift related to the room temperature |
tempRT
| occurs. If
1
deviates from
0
by more than 1 in either direction, |
ang
| can increase with a gradient
defined by slope m
ang
.
temp RT
T
amb
,()
meas
T
amb
,()
meas
T
RT
,()–=
Fig 11. Definition of the angular error
ang
meas
1
T
amb
,()
meas
0
T
RT
,()–
1
0
––=
001aal766
|Δφ
μlin
+ Δφ
temp|RT
|
−α* α
0
− 1°
α
0
|Δφ
ang
|
α
0
+ 1° +α*
m
ang
|Δφ
ang(peak)
|
α
1
