MLX90323 Datasheet, PDF(16/25 Page) Melexis Microelectronic Systems – 4 – 20 mA Loop Sensor Interface with Signal Conditioning and EEPROM

English

English German Russian Spanish Italian Polish Chinese Japanese Korean French Portuguese	Language :

MLX90323 Datasheet, PDF (16/25 Pages) Melexis Microelectronic Systems – 4 – 20 mA Loop Sensor Interface with Signal Conditioning and EEPROM

◁

MLX90323

4 â 20 mA Loop Sensor Interface

with Signal Conditioning and EEPROM

9.3 Calibration procedure

1) Set the desired operating mode and number of gaps. It is also helpful to set T2 and T3 to 1023.

2) At the T1 temperature do a baseline calibration, the span then the offset by using CSGN[1:0] and GN[9:0]

then CSOF[1:0] and OF[9:0]. The T1 temperature is somewhat arbitrary, typically its room temperature. If

the temperature sensor goes down with increasing temperature then the T1 value will be towards the high

end of the applicationâs temperature range. Update the Temp value. Copy the digitized temperature reading

to the T1 box. If one temperature gap is desired then T1 will be the highest digitized temperature value.

3) Lower the temperature to the lowest operating temperature and recalibrate the output using

GNTC1 and OFTC1 only. If the temperature sensor goes down with increasing temperature then raise the

temperature to its maximum value and re-calibrate the output using GNTC1 and OFTC1. Do not change the

T1, OF, or GN values.

4) Raise the temperature until the second temperature point, T2. If the temperature sensor goes down with

increasing temperature then lower the temperature to the T2 value. This point may be arbitrary and can be

based on how far the output has deviated from it's desired value. Re-calibrate the sensor by adjusting

GNTC2 and OFTC2 only.

5) Update the Temp value displayed on the screen. Copy the digitized temperature value to the T2 box. This

must happen AFTER step 4.

6) Repeat steps 4 and 5 for T3 and setting GNTC3, OFTC3. T1, T2, and T3 must be in ascending order.

7) For the last temperature gap, raise the temperature to the highest operating temperature point and re-

calibrate the output using GNTC4 and OFTC4. There is no T4, it is assumed to be 1023 (the maximum value

of the digitized filtered temperature).

For less than four temperature gaps the last temperature point should be set to 1023. This means that the

last gap extends out to the end of the temperature range.

3901090323

Rev 003

Page 16 of 25

Data Sheet

Feb/12

▷