HAL856
DATA SHEET
Step 4: Calculation of Shift and Slope
Software Calibration:
There are two ways to calculate the values for Shift
and Slope.
Use the menu CALIBRATE from the PC software and
enter the values for the registers which are not
adjusted individually. Set the system to calibration
point 1 (angle 1 = 25°), hit the button “Digital Output1”,
set the system to calibration point 2 (angle 2 = −25°),
hit the button “Digital Output2”, and hit the button “Cal-
culate”. The software will then calculate the appropri-
ate Shift and Slope.
Manual Calculation:
1. Set the system to calibration point 1 (angle 1 = 25°)
2. read the register DIGITAL OUTPUT.
For our example, the result is
DIGITAL OUTPUT = DOUT1 = 3291.
This calculation has to be done individually for each
sensor. Now, select an output characteristic from the
selection box “Output Characteristics” and then press
the button “write and store” for programming the sensor.
3. Set the system to calibration point 2 (angle 2 = −25°)
4. read the register DIGITAL OUTPUT again.
For our example, the result is
DIGITAL OUTPUT = DOUT2 = 985.
Step 5: Locking the Sensor
The last step is activating the LOCK function with the
“LOCK” command. Please note that the LOCK function
becomes effective after power-down and power-up of
the Hall IC. The sensor is now locked and does not
respond to any programming or reading commands.
With these measurements and the pre-programming
of the sensor, the values for Slope and Shift are calcu-
lated as:
3968
(985 – 3291)
-------------------------------
Slope =
× 0,1938= –0.3335
Warning: This register cannot be reset!
100%
-------------
(985 – 2048) × (–0.3335)
--------------------------------------------------------------
= 52,22%
Shift =
× 3968 –
4096
0,1938
Write the calculated values for Slope and Shift and a
linear output characteristic ranging from 10% to 90%
output duty cycle into the EEPROM memory.
16
March 23, 2010; DSH000142_002EN
Micronas
MICRONAS [ MICRONAS ]
