HAL800 Datasheet, PDF(9/24 Page) Micronas – Programmable Linear Hall Effect Sensor

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HAL800 Datasheet, PDF (9/24 Pages) Micronas – Programmable Linear Hall Effect Sensor

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HAL 800

2.3. Calibration Procedure

2.3.1. General 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 of the register values.

In this section, programming of the sensor with this

programming tool is explained. Please refer to

Section 5. on page 19 for information about program-

ming without this tool.

For the individual calibration of each sensor in the cus-

tomer application, a two point adjustment is recom-

mended (see Fig. 2â8 for an example). When using

the application kit, the calibration can be done in three

steps:

Step 1: Input of the registers which need not be

adjusted individually

The magnetic circuit, the magnetic material with its

temperature characteristics, the filter frequency, and

low and high clamping voltage are given for this appli-

cation.

Therefore, the values of the following registers should

be identical for all sensors of the customer application.

â FILTER

(according to the maximum signal frequency)

â RANGE

(according to the maximum magnetic field at the

sensor position)

â TC and TCSQ

(depends on the material of the magnet and the

other temperature dependencies of the application)

â CLAMP-LOW and CLAMP-HIGH

(according to the application requirements)

Write the appropriate settings into the HAL 800 regis-

ters.

After writing, the information is stored in an internal

RAM and not in the EEPROM. It is valid until switching

off the supply voltage. If the values should be perma-

nently stored in the EEPROM, the âSTOREâ command

must be used before switching off the supply voltage.

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.

Low clamping voltage â¤ VOUT1,2 â¤ High clamping voltage

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

ADC-READOUT2.

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:

VOUT1 â VOUT2

2048

Sensitivity = ADC-READOUT1 â ADC-READOUT2 * VDD

VOQ = VOUT1 â

ADC-READOUT1 * Sensitivity * VDD

2048

This calculation has to be done individually for each

sensor.

Now, write the calculated values for Sensitivity and

VOQ for adjusting the sensor.

Use the âSTOREâ command for permanently storing

the EEPROM registers. The sensor is now calibrated

for the customer application. However, the program-

ming can be changed again and again if necessary.

Step 3: Locking the Sensor

The last step is activating the LOCK function with the

âLOCKâ command. The sensor is now locked and does

not respond to any programming or reading com-

mands.

Warning: This register cannot be reset!

Micronas

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