National Instruments Hardware

National Instruments data acquisition hardware has a modular design; various combinations can be arranged to satisfy a wide range of customized experimental setups. The signal path starts at the sensor. Sensor output is obtained by a module- a computer card designed to read some number of channels from one or more sensor types. Modules are housed in a chassis, which reads data from all modules. Finally, the chassis passes the data to the computer. Signals are sent and acquired through National Instruments LABVIEW software.

Signal conditioning and calibration options can occur at the module or programmatically in the LABVIEW code. All NI DAQ carts have LABVIEW.

For any piece of hardware, specs and manuals are freely available on National Instruments website. The lab can assist in the creation of plugs and connectors for sensor wires; clients are also welcome to consult the relevant module manuals for the pin-out information needed to prepare their own.

Each module listed comes with its corresponding shielded terminal block- a box with screw terminals that makes connecting sensor wires easy.

Although many of the listed modules are generally available, use varies, and additional modules may be required for an experiment. For new hardware, price-sharing/ownership agreements are negotiable; direct inquiries toward one of the lab contacts.

NI PXI Chassis and modules

  • Chassis: PXI-1042Q (quantity: 1): This chassis is housed on a portable cart and typically available for general use. It is equipped with the following modules:

  • Module: PXI-8187; embedded controller (quantity: 1): This module combines with the PXI-1042Q chassis to form a PC.

  • Module: PXI-7833R; configurable I/0 (quantity: 1): This module communicates between LABVIEW and various signal paths via its 8 input and 8 output channels (16 bit res, ±10V). Typically, it is used in conjunction with the NI-SCB 68, a shielded terminal block with 68 pins (screw terminals).

  • Module: PXI-6251; reads SCXI chassis (quantity: 1): Although it can be used otherwise, this module is typically used to connect the PXI-1042Q to the SCXI-1000 (a 4-slot sensor module chassis). The PXI 6251 has 16 analog input channels (16 bit res, ±10V).

  • Module: Systran compact PCI; fiber-optic link combines with MTS daq (quantity: 1): This module converts signals into fiber-optic output which allows for the combination of the PXI-1042Q daq with the MTS daq.

NI SCXI Chassis and modules

  • Chassis: SCXI 1000; 4 slots (quantity: 1): This chassis has 4 slots that can hold any SCXI module. It is typically paired with the NI PXI-1042Q.
  • Chassis: SCXI 1001; 12 slots (quantity: 1): This chassis has 12 slots that can hold any SCXI module. It is paired with a PC on an independent cart, which is commonly used for the 1000 kip (454 metric ton) load frame, but can be repurposed when the load frame is inactive, or within proximity to the existing setup. Note: For most purposes, the SCXI 1001 needs either a 1520 or 1540 module on-board as a communicator.
  • Module: SCXI-1520; 8-chan. universal strain with SCXI-1314 terminal block (quantity: 2): This module can simultaneously sample up to 8 channels. It accommodates quarter, half, and full bridge completion. It has programmable excitation (0-10V), gain (1-1000), and filters. Designed to read a voltage range, this module can also satisfy other functions, such as reading a DC LVDT.
  • Module: SCXI-1540; 8-chan. LVDT with SCXI-1315 terminal block (quantity: 1): This module can read up to 8 AC LVDTs. It has programmable 1-3 Vrms excitation for various frequencies (2.5, 3.3, 5, 10 kHz). It has programmable, per channel input ranges (.05 to 6 Vrms). It supports multichannel synchronization.
  • Module: SCXI-1102; 32-chan. TC & voltage with SCXI-1300 terminal block (quantity: 1): This module reads up to 32 open-thermocouple or voltage channels. It has 2Hz lowpass filtering per channel, and overvoltage protection to ±42 V. A few channels are dedicated to the 1000 kip (454 metric ton) load frame.
  • Module: SCXI-1141; 8-chan. low-pass elliptical filter with SCXI-1304 terminal block (quantity: 1): This module is ideal for anti-aliasing applications, and has 8 channels with programmable gain (±50 mV to ±5 V). It also has a programmable filter per module (10-25 kHz), and can apply 8th-order elliptical filters.
  • Module: SCXI-1121; 4-chan. isolation amp. w/ excitation, SCXI-1321 terminal block (quantity: 3): This module had 4 channels available for amplifying isolated analog input signals from millivolts up to ±250 V. It also has lowpass filtering and shunt calibration capability.

MTS Hardware

The MTS Structural Testing System (STS) data acquisition system has similar capability to NI, but with different components and advantages/limitations. The STS has a wire network that accommodates a variety of sensors (26 strain, 10 LVDT, 3 encoder, and 3 accelerometer channels) and can reach any location in the lab.

Sensor wires

For strain, the sensor wires have a ‘completion box’ that can be fitted with shunt resistors and gage resistors in order to shunt calibrate (in the software) and to accommodate the various bridge completion circuits.

Encoder, LVDT, and accelerometer wires are configured and plugged for lab sensors.

All sensors have adequate length (shielded) to reach anywhere in the strong floor. They are routed in the basement and brought up (through passages in the strong floor) near the test, which helps greatly with organization.

For all sensors, pin schematics are available upon request. The lab can also assist in making plugs.

Controller

The sensor wires link into modules on the MTS controller. These modules can be swapped to customize an experiment; however, it is favorable to swap/expand modules with the NI equipment.

The controller has signal conditioning and calibration options that are operable at the desktop (in the center of operations, known as the control room).

Maximum capacity (combining systems)

Presently, using the fiber-optic module to combine the NI and STS DAQ systems would provide 42 strain gage, 18 LVDT, 3 encoder, 3 accelerometer, and 3 actuators. It is possible to increase the number of certain types of channels with additional NI modules.

Note: strain channels can be exchanged to read DC LVDTs, accelerometers, etc.

Equipment and Instrumentation List

The following equipment is generally (depending on suitability or current use) available for any visiting tester:

LVDTs

  • ±0.25 inches, 0.64 cm (3)                                   
  • ±1 inches, 2.54 cm (7)                                   
  • ±3 inches, 7.62 cm (2)                                   

All are plugged, configured, ready for use, non-cert. calibrated in lab. 

Encoders

  • 14.5 inch (36.8 cm) range (3)

Plugged, configured, ready for use

Accelerometers

  • 8G (3)
  • 20G (2)

Plugged, configured, ready for use

Extensometers

  • Circumferential (1)                                   
  • Normal, 4.5 and 6 inch (11.4 and 15.2 cm) ext. kits (1)

Plugged, configured, ready for use, non-cert. calibrated in lab

Load Cells

  • 1 Kip (4.45 kN) shear (4)
  • MT 200 Kip (890 kN) (1)

Plugged, configured, ready for use, non-cert calibrated in lab

Plugs

28 male 6-pin military connectors (enough to connect to all STS strain channels).