HAL815
ADVANCE INFORMATION
Step 2: Calculation of VOQ and Sensitivity
The calibration points 1 and 2 can be set inside the
specified range. The corresponding values for VOUT1
and VOUT2 result from the application requirements.
V
5
4
3
2
1
0
Clamp-high = 4.5 V
Calibration point 1
Low clamping voltage ≤ VOUT1,2 ≤ High clamping voltage
V
OUT
For highest accuracy of the sensor, calibration points
near the minimum and maximum input signal are rec-
ommended. The difference of the output voltage
between calibration point 1 and calibration point 2
should be more than 3.5 V.
Set the system to calibration point 1 and read the reg-
ister ADC-READOUT. The result is the value ADC-
READOUT1.
Now, set the system to calibration point 2, read the
register ADC-READOUT again, and get the value
ADC-READOUT2.
Clamp-low = 0.5 V
Calibration point 2
–30 –20 –10
0
10
20
30 °
With these values and the target values VOUT1 and
VOUT2, for the calibration points 1 and 2, respectively,
the values for Sensitivity and VOQ are calculated as:
Angle
V
− V
OUT2
OUT1
2048
Fig. 2–7: Example for output characteristics
Sensitivity =
*
V
ADC-READOUT1 − ADC-READOUT2
DD
ADC-READOUT1 * Sensitivity * V
2048
DD
V
= V
−
OQ
OUT1
This calculation has to be done individually for each
sensor.
Step 1: Input of the registers which need not be
adjusted individually
Next, write the calculated values for Sensitivity and
VOQ into the IC for adjusting the sensor.
The register values for the following registers are given
for all applications:
The sensor is now calibrated for the customer applica-
tion. However, the programming can be changed again
and again if necessary.
– FILTER
Select the filter frequency: 500 Hz
– RANGE
Step 3: Locking the Sensor
Select the magnetic field range: 30 mT
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.
– TC
For this magnetic material: 6
– TCSQ
For this magnetic material: 14
Warning: This register cannot be reset!
2.3.2. Calibration of the Angle Sensor
– CLAMP-LOW
For our example: 0.5 V
– CLAMP-HIGH
For our example: 4.5 V
The following description explains the calibration pro-
cedure using an angle sensor as an example. The
required output characteristic is shown in Fig. 2–7.
Enter these values in the software, and use the “write
and store” command for permanently writing the val-
ues in the registers.
– the angle range is from −25° to 25°
– temperature coefficient of the magnet: −500 ppm/K
10
Micronas
MICRONAS [ MICRONAS ]
