Eddy Current Array

A more advanced form of eddy current testing, eddy current array uECAses multiple eddy current coils, typically of the same design, arranged in an organized pattern in a single probe. This allows users to cover a larger area in a single pass. ECA can be deployed for tube testing (condenser tubes, for example) and for surface applications (welds, for example).

Eddy current array uses multiplexing which involves activating and deactivating coils in specific sequences to minimize the interference between the coils that are in close proximity to each other. Doing so, it is possible to use coils as transmitters and receivers while avoiding mutual inductance.

ECA is a computerized technique, which comes with multiple advantages. One of them is the ability to display data in a form of a C-scan. C-scan imaging (2D or 3D) is a very intuitive way to present data and generally makes analysis faster and/or easier.

ECA_C-scan_example1 ECA_C-scan_example2

Replacing Traditional NDT Methods with ECA

Eddy current array is increasingly being used to replace traditional methods like MT (MPI), PT (LPI) and ACFM for surface inspections, increasing speed of inspection, reducing downtime and eliminating any needs for harsh chemicals.


  • Increased inspection speeds & detection capabilities
  • Increase in surface area that can be scanned
  • Less operator dependent
  • C-Scan imaging allows for an easier assessment of the results meaning less experienced technicians can perform acquisitions
  • Environmentally friendly
  • Result traceability & post process analysis
  • Array probes can easily be designed to be shaped to specification

Main portable instruments available for surface ECA Inspections

For obvious reasons, portable solutions offer a number of advantages where mobility is essential, such as in rope access applications, scaffolding access applications, long weld inspection and in-service inspections in general.



Olympus OmniScan® MX ECA

Launched around 2004, the OmniScan MX ECA is a compact inspection instrument. Its two Li-ion batteries provide up to 6 hours of autonomy. The OmniScan MX comes bundled with an embedded software.

Features Pros & Cons
• 321 × 209 × 125 mm (12.6 × 8.2 × 5.0 in)
• 21 cm (8.4 in) TFT LCD, 800 × 600 pixels
• 32 ECA channels
• Live impedance plane
• 2D C-scan imaging
• Encoded scanning
• Compact
• Relatively light
• Limited probe catalog for surface applications (mainly aerospace)
• Limited to 32 channels (needs external multiplexer to support up to 64 channels)
• No export tools for the PC/desktop software
• Limited reporting capabilities
• Small screen with limited resolution


Eddyfi Reddy®

Launched in 2015, Reddy is a rugged instrument designed to meet the unique in-service eddy current array (ECA) surface inspection needs of the oil & gas, power generation, and aerospace industries. Its two Li-ion batteries offer up to 8 hours of autonomy. Reddy comes bundled with the Magnifi GO software.

Features Pros  &  Cons
• 355 × 288 × 127 mm (14.0 × 11.3 × 5.0 in)
• 26.4 cm (10.4 in) multi-touch TFT LCD, 1024 × 768 pixels
• Up to 96 ECA channels
• Configuration wizards
• Live impedance plane
• 2D C-scan imaging
• Encoded scanning
• 100 GB internal solid-state disk drive
• Technology available to enable crack depth sizing
• Large touchscreen with high-resolution and anti-glare
• Extensive catalog of standard surface probes for ferrous and non-ferrous applications
• User-friendly inspection setup with configuration wizards
• Desktop analysis capabilities enables 3D C-scan imaging, more
• Defect table and full reporting capabilities• Wi-Fi Bluetooth not yet activated
• Not very lightweight

Side by Side Comparison 

OmniScan MX ECA
Design Year 2015 2004
ECA Support Yes Yes
Channels 96 32
Frequency Rate 5 Hz–10 MHz 20 Hz–6 MHz
Generator Output Max. 20 Vpp Max. 12Vpp
Sampling Rate ≤50 kHz ≤15 kHz
Display 26.4 cm (10.4 in) multi-touch, LCD, 1024×768 px 21 cm (8.4 in) TFT LCD, 800×600 px
Sealed/Fanless Enclosure Yes Yes
Wi-Fi/Bluetooth Yes(not enabled) No
USB Ports 3×2.0 3×1.1
Internal Storage 100+ GB None
Encoders 2 2
Export to Desktop Software Yes No
Reporting Complete Partial
Multi-Touch Yes No
Setup Wizard Yes No
Live Impedance Plane Yes Yes