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High Channel Count to a Single Channel,a Scalable PXI Based Dynamic Signal

Acquisition System2009 NI Week – August 4th

Doug WilsonStephen MasulloPVI Systems, Inc.

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System OverviewSingle or Multiple Chassis w/ControllerGPS Synchronization

Excitation DevicesTransducers

GigESwitch

Host Computer

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Development Overview• Scalable Data Acquisition System

Designed for a Government Lab Advanced DAQmx Help from NI S&V Support Group

• Design Goals Flexible Data Acquisition Engine Scalable Reconfigurable to Support Multiple Test Programs Geographically distributed

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Functional Capabilities•Channel Configuration Management •Hardware Setup and Control•Data Quality Checking•Data Monitoring•Data Streaming•Frequency Processing•Data File Management•Automated Acquisition

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NI Hardware – PXI or PXIe

Chassis with Controller

Timing Card(s) Data Acquisition Modules

Embedded

Or

External

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Timing Synchronization Options

GPS

Master/Slave Configuration

Master Slave #1

Slave #2

GPS

All Master Configuration

External Clock

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High Channel Count Expansion Options

Slave #2

Slave #6 Slave #7

Master

Slave #1

Slave #4 Slave #5

Slave #3

Slave #8 Slave #9

Master/Slave Expansion

Chassis #1

GPS

Chassis #2

GPS

Chassis #3

GPS

Chassis #4

GPS

Chassis #N

GPS

All Master Expansion

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Software Flow Diagram

Host Main

Server Main

Source Control

Acquisition Control

Data Monitoring

Data Plotting

Data Export

Data File Download

Acquisition Hardware

TCP Messaging

Channel Config Utility

Data Streaming

Host Side Server Side

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Acquisition Control Initialization

• NI-Sync Timing• DAQmx Init• Trigger Init• Sync Pulse Init (on Master Chassis only)• Connect Start Trigger

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Acquisition Control - Acquisition

Init Circ BufferStart DAQmx TasksIssue Start Pulse

Acquisition Loop

Data Monitor Loop

Circular Buffer→ RMS→ Peak →Host→ Waveform

DAQmx ReadWrite to Circular BufferWrite to TDMS (if logging)

AI Start

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Data Formats• Time Data – TDMS File on Each Server

Configuration for All Servers Scaling Coefficients Raw Data Recorded Errors

• Frequency Data – TDMS File on Host Configuration for All Servers Selected Frequency Data (PS, PSD, FRF) Recorded Errors

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Software Design – Host Main

• Acquisition Functions• Configuration Utility• Source Control• Acquisition Control• Signal Monitor

• File Functions• Data Plotting and Freq Processing• Download / Merge Data Files• File Export• File Configuration and Error Display

• Utilities Functions• View Time of Master Chassis• Reset Communications

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Configuration Management• Defines All Test

Parameters• System• Frequency• Analog Input• Analog Output

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Source Control• Output Waveform• Output Amplitude

Master Per Channel

• Sine Output Frequency• Coordinated Digital

Triggering with Analog Output

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Acquisition Control

• Data File Path• Acquisition Mode

Continuous Finite Frequency

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Signal Monitoring• Bar Graph Indicator

Max RMS Instantaneous Peak

• Range Setting Per Channel Auto Range All Chan

• Per Channel Time or Frequency Display

• Multi-Plot• Error Indicators

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Frequency Processing• Time Data Streamed to Disk• Frequency Processing on Servers

• Results transferred to Host• Display Parameter Control

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Time Data Display• Playback from TDMS File• Full Time History• Windowed Time Display

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Frequency Data Display and Processing• Playback with

Frequency Processing• Selectable Parameters

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Automated Acquisition Control• Programmatic Control - Active-X• Update Front Panel Controls• Generate Events• Control entire experiment

multiple acquisition & source setups

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Future Development

• Expanded Range of Validated NI Hardware• Enhanced User Interface• Integrated Post Processing Tools• Interface to Third Party Post Processing Tools

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System Demonstration

• Demonstrates Multiple PXI Chassis Configuration• Live Linear Acoustic Array Data Streaming• Live Processing

See the live demo atPVI Systems Booth # 433