DEWESOFT SIRIUS User Manual

SIRIUS®
Digital filters
A digital filter is a system that performs mathematical operations on a sampled, discrete-time signal to reduce or
enhance certain aspects of that signal. In comparison to analogue filters, digital filters require complex electronics (i.e. a
digital signal processor – aka. DSP) to calculate the filter-results.
There are 2 types of digital filters that will be used in the following discussion:
IIR filter
In theory the impulse response of an IIR (Infinite Impulse Response) filter does not become exactly zero past a certain
point, but continues indefinitely. In practice, the impulse response even of IIR systems usually approaches zero and can
be neglected past a certain point. IIR filters can have the same characteristics as analogue filters.
The main advantage that digital IIR filters have over FIR filters is their efficiency in implementation. A disadvantage is
that linear phase is difficult to achieve.
FIR filter
A FIR (Finite Impulse Response) filter, is a filter whose impulse response (or response to any finite length input) is of
finite duration, because it settles to zero in a finite time.
An FIR filter has a number of useful properties which sometimes make it preferable to an infinite impulse response
(IIR) filter. FIR filters:
require no feedback: i.e. any rounding errors are not compounded by summed iterations
are inherently stable: since the output is a sum of a finite number of finite multiples of the input values
can easily be designed to be linear phase
The main disadvantage of FIR filters is that considerably more computation power is required compared to an IIR filter
with similar sharpness or selectivity, especially when low frequency (relative to the sample rate) cut-offs are needed.
However many DSPs (digital signal processors) provide specialized hardware features to make FIR filters
approximately as efficient as IIR for many applications.
6.1.1.7 Oversampling
Oversampling means, that the sampling rate of the ADC is significantly higher, than its output rate. Oversampling
improves resolution, reduces noise and helps avoid aliasing and phase distortion by relaxing anti-aliasing filter
performance requirements.
EXAMPLE 1
When we want to measure a 1kHz sine-wave signal, the Nyquist theorem dictates, that we
need at least a sample rate of 2kHz. When we now sample the signal with 4kHz (instead of
the minimum required 2kHz), we oversample by the factor of 2.
6.1.2 Filter Design
Since ideal filtering is not possible, we need to carefully design our filters to achieve the desired results.
One important goal is that want to have a very sharp damping, so we need a high-order filter, which in turn means, that
we will use a digital filter. Moreover we want to have a linear phase, so we choose a FIR filter (the performance of the
DSP in Sirius® is powerful enough to handle this demanding computation).
Another important goal is to minimise errors introduced by aliasing. So the FIR filter alone will not be sufficient (since
digital filters are subject to aliasing).
In the following examples, we assume that we want to measure a signal between 0 and 800Hz and we will consider how
higher-frequency components in the input signal affect the measurement result.
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DEWESOFT SIRIUS Specifications

General

Resolution	24-bit
Isolation	Channel-to-channel and channel-to-ground
Interface	USB
Software	DewesoftX data acquisition software
Bandwidth	DC to 50 kHz (depending on module type)
Humidity	non-condensing
Analog Inputs	Voltage, IEPE, Charge, Current, Strain Gage, Thermocouple, RTD, Resistance, LVDT, Bridge

Summary

Notice

Safety Instructions

Critical safety guidelines for operating the SIRIUS system.

Getting Started

Software Installation

Guide to installing DEWESoft software for the SIRIUS system.

DEWESoft Installation

Step-by-step instructions for installing DEWESoft software.

Connecting a Single Slice

Instructions for connecting a single SIRIUS slice to a PC via USB.

Analogue Channel Setup

Troubleshooting

Common issues and solutions for SIRIUS device detection by DEWESoft.

Enclosure Overview

SIRIUS-SBOX2 Overview

SIRIUS-SBOX2 Specifications

Technical and physical specifications for the SIRIUS-SBOX2.

SIRIUSf-SBOX Overview

SIRIUSf-SBOX Specifications

Technical and physical specifications for the SIRIUSf-SBOX.

SIRIUS-R2D Overview

SIRIUS-R8 Overview

SIRIUS-R8 Specifications

Technical and physical specifications for the SIRIUS-R8.

SIRIUS-R8D Overview

SIRIUS-R8D Specifications

Technical and physical specifications for the SIRIUS-R8D.

SIRIUS Measurement Modules

Data Transfer Overview

USB Data Transfer

SIRIUS Dual Core Technology

SIRIUS HD Series Technology

SIRIUS HS Series Technology

SIRIUS Slice Configuration

Options for configuring SIRIUS slices with various modules.

SIRIUS Dual Core Specifications

Detailed specifications for SIRIUS Dual Core modules.

SIRIUS HD and HS Specifications

Specifications for SIRIUS High Density and High Speed modules.

General Specifications

ACC and ACC+ Modules

Details on ACC and ACC+ modules for sound and vibration IEPE.

ACC Module Specifications

Technical specifications for the SIRIUS ACC module.

ACC+ Module with Counter

CHG and CHG+ Modules

Details on CHG and CHG+ modules for charge measurements.

CHG Module Specifications

Technical specifications for the SIRIUS CHG module.

HV Modules

Information on HV modules for high voltage measurements.

HVv2 Module Specifications

Technical specifications for the SIRIUS HVv2 module.

LV and LV+ Modules

Details on LV and LV+ modules for voltage and strain measurements.

LVv2 Module Specifications

Technical specifications for the SIRIUS LVv2 module.

LV+ Module with Counter

MULTI Modules

Details on MULTI modules for multi-purpose analogue/digital I/O.

MULTI Module Specifications

Technical specifications for the SIRIUS MULTI module.

STGM and STGM+ Modules

Information on STGM modules for strain gauge and voltage measurements.

STGMv2 Module Specifications

Technical specifications for the SIRIUS STGMv2 module.

STGM+ Module with Counter

STGM-DB Module

STG and STG+ Modules

Information on STG modules for strain gauge, voltage, and resistance.

STGv2 Module Specifications

Technical specifications for the SIRIUS STGv2 module.

STG+ Module with Counter

HD-ACC Modules

Details on HD-ACC modules for high density applications.

HD-ACC Module Specifications

Technical specifications for the SIRIUS HD-ACC module.

HD-LV Modules

Details on HD-LV modules for high density low voltage measurements.

HD-LV Module Specifications

Technical specifications for the SIRIUS HD-LV module.

HD-STGS Modules

Details on HD-STGS modules for high density strain gauge measurements.

HD-STGS Module Specifications

Technical specifications for the SIRIUS HD-STGS module.

HS-ACC and HS-ACC+ Modules

Details on HS-ACC/ACC+ modules for high speed sound/vibration.

HS-ACC Module Specifications

Technical specifications for the SIRIUS HS-ACC module.

HS-ACC+ Module with Counter

HS-CHG and HS-CHG+ Modules

Details on HS-CHG/CHG+ modules for high speed charge measurements.

HS-CHG Module Specifications

Technical specifications for the SIRIUS HS-CHG module.

HS-CHG+ Module with Counter

HS-HV Modules

Details on HS-HV modules for high speed high voltage measurements.

HS-HV Module Specifications

Technical specifications for the SIRIUS HS-HV module.

HS-LV and HS-LV+ Modules

Details on HS-LV/LV+ modules for high speed low voltage measurements.

HS-LV Module Specifications

Technical specifications for the SIRIUS HS-LV module.

HS-LV+ Module with Counter

HS-STG and HS-STG+ Modules

Details on HS-STG/STG+ modules for high speed strain gauge measurements.

HS-STG Module Specifications

Technical specifications for the SIRIUS HS-STG module.

HS-STG+ Module with Counter

Measurement

Filtering Capabilities

Covers filtering capabilities of SIRIUS modules and DEWESoft software.

Aliasing in Signal Processing

Filter Design Principles

Sampling and Digital Filtering

Oversampling and Digital Filtering

Analogue, Oversampling, and Digital Filters

Combined effect of analogue, oversampling, and digital filtering.

SIRIUS DualCore & HD Anti-Aliasing

Strategies used by SIRIUS DualCore/HD for anti-aliasing.

SIRIUS ADC Oversampling

SIRIUS Digital ADC Filter

SIRIUS Anti-Aliasing Filter

Overview of filters and sampling rates for anti-aliasing.

DEWESoft Custom Low Pass Filters

Advanced Topics

Wireless Connection Setup

Hosted Network on Windows 7

Android WiFi Connection

Android VNC Connection

Data Synchronization

Importance and methods of synchronizing data from multiple channels.

Synchronization Options

Synchronizing Multiple SIRIUS Chassis

Synchronizing Across Multiple PCs

Firmware Upgrade Procedure

Guide on how to upgrade the firmware of SIRIUS measurement systems.

Firmware Upgrade Preparation

Steps required before performing a firmware upgrade.

Downloading Firmware and Tools

Instructions for downloading necessary firmware and upgrade tools.

Extracting Firmware Files

System Firmware Upgrade

Process for uploading system firmware to SIRIUS.

Module Firmware Upgrade

Process for upgrading firmware for individual SIRIUS modules.

Firmware Upgrade Troubleshooting

Solutions for common issues during firmware upgrades.