Board Mount Pressure Sensor

AMS 6915 SERIES

© 2022, Analog Microelectronics GmbH

www.analog-micro.com

Datasheet AMS 6915

– Rev. 2.0

10/13

Calculating the current pressure and temperature value

The digital output values for pressure (14-bit value) and temperature (11-bit value) have to be converted in

order to generate the desired information on pressure and temperature in physical units.

The current pressure in mbar (or PSI) is calculated from the digital pressure value using the following

equations:

pp =

Digoutp(p) – Digoutpmin

Sensp

+ p

min

with

Ssensp =

Digoutpmax – Digoutpmin

pmax – pmin

(1)

wherein p is the current pressure in mbar

2, p

min is the specified minimum pressure and pmax is the specific

maximum pressure in mbar; depending on the specified pressure range, Digoutp(p) is the current digital 14-

bit pressure value in counts, Digoutpmin and Digoutpmax are the digital pressure values at minimum and

maximum specified pressure in counts and Sensp is the sensitivity of the pressure sensor in counts/mbar.

The current sensor temperature in °C is calculated from the digital temperature output value using the

following equation:

TT =

DigoutT(T)

2048

∗ 200 °C – 50 °C

(2)

Therein T is the current sensor temperature in °C and DigoutT(T) is the current 11-bit digital temperature

output value in counts.

Example:

At the digital output of an AMS 6915-0005-D-B (-

5 … 5 mbar bidirectional differential sensor) the following

data bytes 1 … 4 are read:

Byte 1: 00101100

Byte 2: 11001101

Byte 3: 01011100

Byte 4: 11100000

Taking the last 14 bits of byte 1 and byte 2 the current 14 bit digital pressure value is:

Digoutp(p) = 10110011001101bin counts = 2CCDHex counts = 11469Dec counts

and with the first 11 bits of byte 3 and byte 4 the digital temperature value is:

DigoutT(T) = 01011100111 bin counts = 2E7Hex counts = 743Dec counts.

For AMS 6915-0005-D-B the following values are specified:

pmin = -5 mbar, pmax = 5 mbar and Digoutpmin = 1638, Digoutpmax = 14745

Using these values and equation (1) the current pressure in mbar can be calculated:

pp =

(11469 − 1638) counts

(13107 / 10) counts / mbar

+ (-5) mbar = 2.501 mbar

Using equation (2), the current sensor temperature in °C is calculated as:

TT =

(743 ∙ 200) counts∙°C

2048 counts

− 50 °C = 22.6 °C

2 If the current pressure is required in another physical unit, we suggest calculating the current pressure value in mbar as

described above and converting the value into the required physical unit then.