MS5540-CM Measurement Specialties Inc., MS5540-CM Datasheet - Page 10

• Manufacturer Part Number: MS5540-CM
• Description: MODULE BAROMETER MINITURE SENSOR
• Manufacturer: Measurement Specialties Inc.

Specifications of MS5540-CM

• Pressure Type: Absolute
• Operating Pressure: 0.15 ~ 0.16 PSI, 10 ~ 1100 mbar
• Output: Digital
• Voltage - Supply: 2.2 V ~ 3.6 V
• Termination Style: PCB
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 6.2 x 6.4mm Module
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 223-1098-2

NOTES
1) Readings of D2 can be done less frequently, but the display will be less stable in this case.
2) For a stable display of 0.1 mbar resolution, it is recommended to display the average of 8 subsequent
DA5540C_001
0005540C1193 ECN 1037
pressure values.
Read calibration data (factory calibrated) from
C1: Pressure sensitivity
C2: Pressure offset
C3: Temperature coefficient of pressure sensitivity (10 Bit)
C4: Temperature coefficient of pressure offset
C5: Reference Temperature
C6: Temperature coefficient of the temperature
Calculate temperature compensated pressure
Offset at actual temperature:
Sensitivity at actual temperature:
Temperature compensated pressure:
Difference between actual temperature and reference
temperature:
Actual temperature:
Read digital temperature value from MS5540
Convert calibration data into coefficients:
Read digital pressure value from MS5540
Word1, Word2, Word3 and Word4 (4x16 Bit)
Display pressure and temperature value
OFF = C2*4 + ((C4-512)*dT)/2
SENS = C1 + (C3*dT)/2
X = (SENS * (D1-7168))/2
P = X*10/2
dT = D2 - UT1
TEMP = 200 + dT*(C6+50)/2
(see bit pattern of Word1-Word4)
Calculate calibration temperature
Fig. 3: Flow chart for pressure and temperature reading and software compensation.
Calculate actual temperature
PROM of MS5540
5
+ 250*10
UT1 = 8*C5+20224
D1 (16 Bit)
D2 (16 Bit)
Start
10
14
(0.1 mbar resolution)
+ 24576
- OFF
10
12
(0.1° C resolution)
(15 Bit)
(12 Bit)
(10 Bit)
(11 Bit)
February 20th, 2008
(6 Bit)
dT(D2) = D2 - T
TEMP(D2) = 20°+dT(D2)*TEMPSENS
OFF(D2) = OFFT1+TCO*dT(D2)
SENS(D2) = SENST1+TCS*dT(D2)
P(D1,D2) = D1*SENS(D2)-OFF(D2)
SENST1
OFFT1
TCS
TCO
T
TEMPSENS
ref
Basic equations:
ref
dT
TEMP = 391
OFF
SENS = 49923
X
P
Word1 = 46940
Word2 = 40217
Word3 = 25172
Word4 = 47212
C1 = 23470
C2 = 1324
C3 =
C4 =
C5 =
C6 =
D1 = 16460
D2 = 27856
UT1 = 25248
Example:
= 2608
= 39.1 ° C
= 5220
= 23093
= 9716
= 971.6 mbar
737
393
628
25
10