DirectShear™ PXI Control Unit

Capacitive Shear (CS) Series | CSU-1001-PXI


Product Description

The CSU-1001-PXI AC/DC Capacitive Sensor Unit (CSU) is a fully integrated analog synchronous modulation/demodulation system that provides the ability to measure mean and fluctuating quantities of interest, e.g., wall shear stress or pressure, using a capacitive sensor. The CSU provides low-noise power to the sensor head and conditions the analog voltage signal received from the sensor head for output to a data acquisition system. Capacitive sensing at DC is achieved by shifting the sensor baseband frequencies to a modulated signal and demodulating the returned signal from the sensor, enabling simultaneous real-time measurement of both mean and dynamic components.


Sensor Options:

This control unit pairs with the following sensor.

Features and Benefits

  • Ability to measure mean and fluctuating quantities using a variety of capacitive devices
  • Integrated rechargeable lithium-ion battery system minimizes power line noise
  • Multi-pin shielded sensor connector provides supply voltages and carrier signals
  • System status and battery voltage LED indicators

Additional Required Equipment

  • The following additional components and specifications are recommended for AC and DC testing/calibration with the capacitive sensor control unit:
  • CSU-compatible capacitive sensor head and cable
  • RG58 coaxial cable with BNC connectors
  • Data acquisition system (DAQ) – ac/dc measurement
    • Sensing Range: ±1, ±5, ±10V – sensor dependent (see datasheet)
    • Resolution: 18+ bits
    • Sampling frequency:
      • Sensor dependent w/ analog filter between sensor output and analog-todigital converter (ADC)
      • 100+ kS/s w/o analog filter
  • Digital multimeter – DC measurement only
    • 6.5 digits with power line cycle (PLC) integration
    • o DAQ or PC connection (e.g., GPIB)

What is the typical application for DirectShear-Capacitive Sensors?

DirectShear-Capacitive Sensors are typically used in low-speed wind tunnel testing applications. 

What other capabilities does the PXI card have in addition to powering the device?

This control unit only uses the PXI power and does not use other PXI features such as device control and use of backplane signals. IC2 offers the PXI option to reduce the overall footprint of the device for customers who are space limited. We are considering incorporation of advanced PXI capabilities in future generations of the control unit.

What is the difference between the H2U and PXI control units?

The H2U version is a standalone unit that runs on its own battery powered system and provides location flexibility, but is the larger and more expensive of the two options. The PXI model was developed to provide our customers a minimized overall footprint of the control unit, but does not utilize advanced PXI features at this time.

Does each sensor need its own control unit?

Yes. Each sensor requires a dedicated control unit and each unit supports a single sensor at a time; however, multiple sensors can be paired with a single control unit in cases where spares or different sensor types are desired. Engineering services are available for customers who desire custom configurations of control units to support multiple sensors.