Instrumentation for Fast Hybrid Testing at CU NEES

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Instrumentation for Fast Hybrid Testing at CU NEES

• Robb Wallen
• Instrumentation Engineer

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Data Sources
SCRAMNet Deterministic Optical Network (14)
Gigabit Ethernet LAN (2 x Cisco 3550 Switches)
(13)
Data Sources
Neespop.Colorado.Edu Remote Collaboration Host (1)
NI Supplementary Data Acquisition and Control
System (11)
Real-time Computation Target (OpenSEES/ETS or
Simulink) (5)
Test Specimen (12)
A/Ds
Neestp.Colorado.Edu Telepresence Portal
and Robotic Camera Control (2)
Realtime Simulation Target (Simulink) (6)
D/As
FPGA
Additional Computation Resources (7)
Videoconference / Telepresence Hardware (3)
MTS Digital Control System (9)
A/Ds
High-speed Actuators (10)
Neesdaq.Colorado.Edu Data Turbine Server Local
Data Repository (4)
Real-time Hosts (8)
Valve Drivers
Video/Still Image Sources (13)
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Network Infrastructure

• Two Networks
• Gigabit Ethernet for non deterministic
  applications
• Shared Common Random Access Memory Network
  (SCRAMnet) for deterministic applications
• Low latency (sub micro second)
• Reflective memory (low host overhead)
• Supports synchronization through network
  interrupts

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MTS Digital Control and Data Acquisition System

• Integrated 48 channel data acquisition for
  conventional transducers (LVDTs, strain gages,
  accelerometers, etc)
• Controls the three high performance
  servo-hydraulic actuators
• Accepts commands from, and writes acquired data
  to SCRAMNet
• Synchronizes hosts on SCRAMNet by generating a
  network interrupt every millisecond

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MTS Channels

• Six channels for each actuator (Command,
  Displacement, Force, Delta P, Valve Command,
  Valve Position)
• 26 Channels with Digital Universal Conditioners
  (DUCs) used for strain, voltage inputs
• 10 LVDT inputs (4 x 0.5 in, 4 x 1.0 in, 2 x 3.0
  in)
• Three accelerometer channels (- 8g)
• Three linear encoder channels
• All data is digitally down sampled and anti-alias
  filtered
• Sampling rates up 1024 Hz with 16 bit resolution

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MTS Transducers
LVDTs
Linear Encoders
Accelerometers
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National Instruments

• PXI/SCXI based data acquisition system

National Instruments PXI Chassis/Controller
FPGA
D/As
SCRAMNet Network
A/Ds
SCRAMNet
Test Specimen
SCXI Modular Signal Conditioner
LVDT Cond 1
LVDT Cond 2
Strain Cond 1
Strain Cond 2
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National Instruments

• PXI Equipment
• 2.4 GHz Embedded Controller running LabVIEW
  Real-Time or WinXP
• SCRAMNet Interface Card
• 3 Million Gate / 40 MHz. Field Programmable Gate
  Array Card with 16 bit Analog IO and Digital IO
• 300 K Sample/Sec. Multifunction IO Card
• 40 unconditioned analog IO channels, 112 digital
  IO channels
• SCXI Equipment
• Two Eight Channel AC LVDT Conditioners
• Two Eight Channel Universal Strain Conditioners
  with Programmable Excitation, Gain, and Filters
• Currently configured for 32 channels of
  conditioned analog input, can be expanded to 96
  channels if necessary

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NI PXI System Special Features

• Flexible, modular instrument and signal
  conditioning architecture
• Real time operating system for deterministic
  program execution (LabVIEW RT)
• FPGA Hardware-In-The-Loop card translates
  LabVIEW software into hardware for parallelized
  operation at 40 MHz.

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NI PXI/SCXI Applications

• Hybrid Data Acquisition System
• Records data from variety of sources
• MTS controller channels
• Numerical model real time data recorder channels
• Onboard data acquisition channels
• Anything else connected to SCRAMNet
• Synchronizes all data with MTS generated SCRAMNet
  interrupt
• Capable of capturing over 500 channels at 1024
  Hz.
• Supplementary Control System
• Route SCRAMNet memory values to analog and
  digital outputs
• FPGA card for special control needs
• Desktop Hybrid system development platform
• Robotic PTZ Video Cameras

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VIC 2D Image Correlation System

• Uses image correlation algorithms to provide
  full-field non-contact displacement and strain
  data for planar specimens
• Up to 30 frames/second at 1024x768 pixels
• Strain and displacement resolution determined by
  distance from specimen and lens configuration,
  down to 1/20 pixel
• Supports virtual strain gages and extensometers
• Captured image data is synchronized with analog
  or digital input signals
• Acquired data is currently not available for
  real-time viewing

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• Thank You!
• Questions?