MS5535C

14 bar Pressure Sensor Module

09/2015

Page 12

Example:

Word1, Word2, Word3 and Word4 (4x16 Bit)

D1 = 17788

D2 = 26603

Start

Convert calibration data into coefficients:

(see bit pattern of Word1-Word4)

Read calibration data (factory calibrated) from

PROM of MS5535C

Read digital pressure value from MS5535C

D1

(16 Bit)

Read digital temperature value from MS5535C

Display pressure and temperature value

Basic equations:

Calculate calibration temperature

UT1 = 8*C5 + 10000

Calculate temperature compensated pressure

Difference between actual temperature and reference

temperature:

dT = D2 - UT1

Actual temperature:

TEMP = 200 + dT*(C6+100)/2

11

(0.1°C resolution)

Calculate actual temperature

D2

(16 Bit)

SENST1

OFFT1

TCS

TCO

TEMPSENS

C1: Pressure sensitivity

(13 Bit)

C2: Pressure offset

(13 Bit)

C3: Temperature coefficient of pressure sensitivity (10 Bit)

C4: Temperature coefficient of pressure offset

(9 Bit)

C5: Reference temperature

(12 Bit)

C6: Temperature coefficient of the temperature

(7 Bit)

calculated results)

Word1 = 18556

Word2 = 49183

Word3 = 22354

Word4 = 28083

C1 = 2319

C2 = 4864

C3 = 349

C4 = 219

C5 = 2002

C6 =

51

TEMP(D2) = 20 + dT(D2) * TEMPSENS

Offset at actual temperature:

OFF = C2 + (C4 - 250)*dT/2

Sensitivity at actual temperature:

SENS = C1/2 + (C3 + 200) )*dT/2

Temperature compensated pressure:

P = SENS * (D1 - OFF))/2

OFF(D2) = OFFT1 + TCO*dT(D2)

SENS(D2) = SENST1 + TCS * dT(D2)

P(D1,D2) = SENS(D2) * (D1

– OFF(D2))

dT

= 587

TEMP = 243

= 24.3°C

OFF

= 14859

SENS = 4198

P

= 4001

= 4001mbar

Fig. 3: Flow chart for pressure and temperature reading and software compensation