MLX90614 family
Single and Dual Zone
Infra Red Thermometer in TO-39
Gain measurement with fixed length FIR filter
Offset compensation
Additional gain filtering with fixed length IIR, storing the result into RAM as IRG.
Gain compensation calculation, the result is stored into RAM as KG
Object temperature:
IR1 sensor:
IR sensor measurement with programmable length FIR filter *.
Offset compensation
Gain compensation
Filtering with programmable length IIR filter**, storing the result into RAM as IR1D.
Calculation of the object temperature. The result is available in RAM as TOBJ1
.
IR2 sensor:
IR sensor measurement with programmable length FIR filter *.
Offset compensation
Gain compensation
Filtering with programmable length IIR filter**, storing the result into RAM as IR2D
Calculation of the object temperature. The result is available in RAM as TOBJ2
.
PWM calculation:
Recalculate the data for PWM with 10 bit resolution
Load data into PWM module
Note*: The measurements with programmable filter length for FIR filter use the same EEPROM cells for N.
Note**: The IIR filter with programmable filter length uses the same EEPROM cells for L.
1
2
Initialization
3
TA Offset meas
OSTa= meas(NTos
IR Offset meas
OSIR= meas(NIRos
IR1 meas
IR1D= meas(NIR)
IR2 meas
IR2D= meas(NIR)
)
)
filtering
TOS= IIR(LTos,OSTa
filtering
IROS= IIR(LIRos,OSIR)
Offset comp
IR1Dcomp= IR1D- IROS
Offset comp
IR2Dcomp= IR2D- IROS
)
TA meas
Gain drift
Gain comp
IR1Dg= IR1Dcomp*KG
Gain comp
IR2Dg= IR2Dcomp*KG
TDATA= meas(NTa
Offset comp
)
IRGm= meas(NIRg
Offset comp
)
filtering
IR1D= IIR(LIR,IR1Dg
filtering
IR2D= IIR(LIR,IR2Dg
TDATAcomp= TDATA-TOS
IRGcomp= IRGm- IROS
)
)
filtering
filtering
IRG= IIR(LG,IRGcomp
TOBJ1 calculation
TOBJ2 calculation
TD= IIR(LTa,TDATAcomp
TA calculation
)
)
KG calculation
PWM calculation
Load PWM registers
3
2
1
Figure 15: Software flow
3901090614
Rev 003
Page 23 of 40
Data Sheet
03/Oct/2007
MELEXIS [ Melexis Microelectronic Systems ]
