HAL1000
2.3. General Calibration Procedure
For calibration in the system environment, the applica-
tion kit from Micronas is recommended. It contains the
hardware for the generation of the serial telegram for
programming and the corresponding software for the
input or calculating of the register values.
In this section, the programming of the sensor using
this tool is explained. Please refer to Section 5. on
this tool.
For the individual calibration of each sensor in the cus-
tomer‘s application, a two-point adjustment is recom-
mended (see Fig. 2–9 for an example). When using
the application kit, the calibration can be done in three
steps:
DATA SHEET
Note:
The magnetic south pole on the branded side
generates negative ADC-READOUT values, the
north polarity positive values.
Then, set the system to the calibration point where the
sensor output must be low, press the key “Readout
B
ON
” and get the second ADC-READOUT value.
Now, adjust the hysteresis to the desired value. The
hysteresis is the difference between the switching
points and suppresses oscillation of the output signal.
With 100% hysteresis, the sensor will switch low and
high exactly at the calibration points. A lower value will
adjust the switching points closer together. Fig. 2–9
shows an example with 80% hysteresis.
By pressing the key “calibrate and store”, the software
will calculate the corresponding parameters for Sensi-
tivity, VOQ, Low-Level, High-Level and store these val-
ues in the EEPROM.
This calibration must be done individually for each
sensor.
The sensor is now calibrated for the customer applica-
tion. However, the programming can be changed
again and again if necessary.
Step 1: Input of the registers which need not be
adjusted individually
The magnetic circuit, the magnetic material with its
temperature characteristics, and the filter frequency,
are given for this application.
Therefore, the values of the following registers should
be identical for all sensors in the application.
– FILTER
(according to the maximum signal frequency)
The 500 Hz range is recommended for highest
accuracy.
– RANGE
(according to the maximum magnetic field at the
sensor position)
– TC and TCSQ
(depends on the material of the magnet and the
other temperature dependencies of the application)
Write the appropriate settings into the HAL1000 regis-
ters.
V
OUT
Hysteresis
(here 80 %)
Sensor
switched off
Sensor
switched on
position
Calibration points
Fig. 2–9:
Characteristics of a position switch
Step 2: Calculation of the Sensor Parameters
less switch. There is a mechanical range where the
sensor must be switched high and where the sensor
must be switched low.
Set the system to the calibration point where the sen-
sor output must be high, and press the key “Readout
B
OFF
”. The result is the corresponding ADC-READ-
OUT value.
Step 3: Locking the Sensor
The last step is activating the LOCK function with the
“lock” key. The sensor is now locked and does not
respond to any programming or reading commands.
Warning: The LOCKR register cannot be reset!
10
March 4, 2004; 6251-528-1DS
Micronas
MICRONAS [ MICRONAS ]
