Data Sheet

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 IR
G
.
Gain compensation calculation, the result is stored into RAM as K
G
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 IR1
D
.
Calculation of the object temperature. The result is available in RAM as T
OBJ1
.
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 IR2
D
Calculation of the object temperature. The result is available in RAM as T
OBJ2
.
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.
Initialization
T
A
Offset meas
OS
Ta
= meas(N
Tos
)
filtering
T
OS
= IIR(L
Tos
,OS
Ta
)
T
A
meas
T
DATA
= meas(N
Ta
)
Offset comp
T
DATAcomp
= T
DATA
-T
OS
filtering
T
D
= IIR(L
Ta
,T
DATAcomp
)
T
A
calculation
T
A
IR Offset meas
OS
IR
= meas(N
IRos
)
filtering
IR
OS
= IIR(L
IRos
,OS
IR
)
IR1 meas
IR1
D
= meas(N
IR
)
Offset comp
IR1
Dcomp
= IR1
D
- IR
OS
filtering
IR1
D
= IIR(L
IR
,IR1
Dg
)
T
OBJ1
calculation
Gain drift
IR
Gm
= meas(N
IRg
)
Offset comp
IR
Gcomp
= IR
Gm
- IR
OS
filtering
IR
G
= IIR(L
G
,IR
Gcomp
)
K
G
calculation
IR offset
Gain comp
IR1
Dg
= IR1
Dcomp
*K
G
IR2 meas
IR2
D
= meas(N
IR
)
Offset comp
IR2
Dcomp
= IR2
D
- IR
OS
filtering
IR2
D
= IIR(L
IR
,IR2
Dg
)
T
OBJ2
calculation
Gain comp
IR2
Dg
= IR2
Dcomp
*K
G
T
OBJ1
T
OBJ2
PWM calculation
Load PWM registers
1
1
2
3
2
3
Figure 15: Software flow
3901090614 Page 25 of 42 Data Sheet
Rev 004 30/Jul2008