HAL800
10
Micronas
2.3.2. Calibration of Angle Sensor
The following description explains the calibration pro-
cedure using an angle sensor as an example. The
required output characteristic is shown in
Fig. 2
–
8
.
–
the angle range is from
25
°
to 25
°
–
temperature coefficient of the magnet:
500 ppm/K
Step 1: Input of the registers which need not to be
adjusted individually
The register values for the following registers are given
for all applications:
–
FILTER
Select the filter frequency: 500 Hz
–
RANGE
Select the magnetic field range: 30 mT
–
TC
For this magnetic material: 1
–
TCSQ
For this magnetic material: 12
–
CLAMP-LOW
For our example: 0.5 V
–
CLAMP-HIGH
For our example: 4.5 V
Enter these values in the software, and use the
“
WRITE
”
command for writing the values in the regis-
ters.
Step 2: Calculation of V
OQ
and Sensitivity
There are 2 ways to calculate the values for V
OQ
and
Sensitivity
Manual Calculation:
Set the system to calibration point 1 (angle 1 =
25
°
)
and read the register ADC-READOUT. For our exam-
ple, the result is ADC-READOUT1 =
2500.
Now, set the system to calibration point 2 (angle 2 =
25
°
), and read the register ADC-READOUT again. For
our example, the result is ADC-READOUT2 =
+
2350.
With these measurements and the targets V
OUT1
=
4.5 V and V
OUT2
= 0.5 V, the values for Sensitivity and
V
OQ
are
This calculation has to be done individually for each
sensor.
Automatic Calibration:
Use the menu CALIBRATE from the PC software and
enter the values 4.5 V for V
OUT1
and 0.5 V for V
OUT2
.
Set the system to calibration point 1 (angle 1 =
25
°
),
hit the button Read ADC-Readout1, set the system to
calibration point 2 (angle 2 = 25
°
), hit the button Read
ADC-Readout2, and hit the button Calculate. The soft-
ware will then calculate the appropriate V
OQ
and Sen-
sitivity.
Now, write the calculated values into the
HAL 800
for
programming the sensor and use the
“
STORE
”
com-
mand for permanently storing the EEPROM registers.
Step 3: Locking the Sensor
The last step is activating the LOCK function with the
“
LOCK
”
command. The sensor is now locked and does
not respond to any programming or reading com-
mands.
Warning:
This register cannot be reset!
4.5 V
0.5 V
2500
2350
Sensitivity =
5 V
2048
*
=
0.3378
V
OQ
= 4.5 V
2048
2500 *
(
0.3378) * 5 V= 2.438 V
0
–
30
1
2
3
4
5
–
20
–
10
0
10
20
30
°
V
Angle
V
OUT
Clamp-high = 4.5 V
Calibration point 1
Clamp-low = 0.5 V
Calibration point 2
Fig. 2
–
8:
Example for output characteristics