EVB90620 Datasheet, PDF (18/39 Pages) Melexis Microelectronic Systems – High precision non-contact temperature measurements

MLX90620
16x4 IR array
7.3.4 Example for To calculations
Let’s assume that we have following EEPROM data for pixel i=2, j=8:
EEPROM address
0x22
0x62
0xA2
0xD4
0xD5
0xD6
0xD7
0xD8
0xD9
0xE0
0xE1
0xE2
0xE3
0xE4
0xE5
Cell name
A_{i ( 2,8)}
B_{i ( 2,8)}
( 2,8)
A_CP
B_CP
CP _ L
CP _ H
TGC
B_{i _ SCALE}
0_ L
0_ H
0 _ SCALE
SCALE
_L
_H
Stored as
2’s complement
2’s complement
unsigned
2’s complement
2’s complement
unsigned
unsigned
2’s complement
unsigned
unsigned
unsigned
unsigned
unsigned
unsigned
unsigned
Cell values (hex)
0xD6
0xC1
0x8F
0xD0
0xCA
0x00
0x00
0x23
0x08
0xE4
0xD5
0x2A
0x21
0x99
0x79
Table 8
Let’s assume that we have the following input data:
V_CP 0xFFD8 65496 , decimal value (compensation pixel readings)
Sign check 65496 32767 V_CP 65496 65536 40
V_IR(2,8) 0x0090 144 , decimal value
Sign check 144 32767 V_IR(2,8) 144
Ta 28.16 C (as calculated in 7.3.2)
Reference routine for To computation:
A_CP 0xD0 208 , decimal value
Sign check 208 127 A_CP 208 256 48
B_CP 0xCA 202 , decimal value
Sign check 202 127 B_CP 202 256 54
3001090620
Rev 4.0
Page 18 of 40
Datasheet IR16x4
19 September 2012