The 4CTA measurement system is a 4-channel hotwire anemometer. Up to 4 hotwire probes can be operated simultaneously. Due to the extreme short response time, the system is particularly suitable for measurements of instationary flow processes. The system is shipped with calibrated and balanced hotwire probes and is ready to use out of the box.
The integrated USB data aquisition reads the sensor signals and sends them to a connected PC, where the raw data is instantly converted to the appropriate velocities.Furthermore additional sensors like microphones or acceleration sensors can be connected. The integrated 5 kHz  lowpass filter avoids alias-effects. Through the implemented barometer and the front connectable temperature sensor a determination of the air density is possible.

By high pass filtering of the velocity fluctuation signals the flow can be made audiable in real-time, giving an intuitive impression of the flow conditions. Since the ear is the best frequency analyser, the systems represents one of the most efficient methods to analyse aeroacoustic problems.

Technical Data
Velocity range 0.1 – 50 m/s in air (calibrated) higher velocities possible, depending on temperature
Frequency resolution 0…5 kHz with 3dB lowpass, unfiltered up to 10 kHz is optional
Ambient conditions for hot-wire probes
Fluid Air, different non-corrosive gases are possible but must be calibrated separately, no particles, no air pollution
Temperature 10…50°C within factory calibration, -10.60°C possible
Humidity Non-condensing
Data acquisition card (option 4CTA-DAQ)
National Instruments USB-6211 (different data acquisition card optional on request)
Analogue inputs 16 channels, 16bit, 250kHz total sampling rate
Analogue outputs 2 channels, 16bit
Digital in- and outputs 4+4 channels, including 1 counter
Further intern components
PT100 amplifier 0…300°C default, configurable
Barometric pressure sensor 800…1100 hPa
CTA-Mainboard Supply and signal conditioning eCTA/eCCT, per hot-wire probe
Power supply
AC 110…264 V, 47-63 Hz, 100 W
DC 11…18 V, min 4 A, 40 W (Binder 712 2 pin)
Configuration of signal inputs and signal outputs – connections front side
1x PT100 temperature sensor Binder 712, 2 pin
up to 4 hot-wire probes Binder 712, 7 pin
Audio volume and channel selection switch
Earphones 3.5 mm audio jack
up to 10 analogue inputs BNC or customized
up to 2 analogue outputs BNC or customized
Digital in- and outputs D-Sub 9 pin or customized
Ambient conditions for electronics
Temperature 5…40°C
Humidity Non-condensing
case (H x B x T) 134 mm x 234 mm x 333 mm
(19’’ 3HE 42TE)