ND Series

Industrial Middle Pressure Sensors

www.SuperiorSensors.com

7

9 System Overview

The ND Series pressure sensor is a fully integrated pressure acquisition system in a sensor module. The acquisition system includes

anti-alias filters, data acquisition, 50/60Hz notch filter, sensor compensation, bandwidth limiting and I/O functions. Refer to the

figure below for the ND Series block diagram.

There are also two user controlled registers that tune the sensor to the specific user requirements. The first register is the Mode

Control register that determines the output pressure range, the corner frequency of the bandwidth limiting filter and enables or

disables the 50/60Hz notch filter.

The second register is the Rate Control register which

controls the rate at which the Data Available (DAV) pin is

asserted. The internal sensor data update rate of 444 Hz

is often much faster than industrial requirements so the

Rate Control register can throttle down the rate at

which the Data Available pin (DAV) is asserted. The DAV

is reset upon each read of the pressure sensor. An

internal model of the Rate Controller is illustrated in the

figure to the right.

Pressure

Sensor

Δ-Sigma

Modulator

Δ-Sigma

Modulator

SAR ADC

SAR ADC

Decimation

4

50/60Hz

Notch

(Sinc1)

4

26 Term

Compensation

Coefficients

4

SPI/I2C

Interface

Va

To

Vs

MCU

DAV

nRST

Rate Control

User Control Registers

Mode Control

1b

Enable

3b

BW

Control

3b

Range

Control

BW Limit

IIR

(2nd Order)

Compensation

FPU with

Linearization

Anti-Alias

Filter

Rate

Controller

HW

Interface

Anti-Alias

Filter

MISO/SDA

MOSI/SCL

SCK

nSS

Down Counter

Rate Control

Register

S

R

Q

Zero

Reload Value

Internal Update

(fUPDATE)

Data Read

DAV