Cygnus Instruments

Cygnus 1 Intrinsically Safe

The Cygnus 4PLUS is a small and tough multi-mode ultrasonic thickness gauge which features an A-scan display, simple to use sequential data logging and manual and automatic gain control.

Designed for the harshest of environments, with a simple to use keypad, intuitive menus and a colour LCD display which can be viewed in all lighting conditions.

The twin shot injection moulded enclosure has a soft but durable TPE outer skin which is comfortable to hold and protects against bumps while the hard internal shell offers maximum strength and environmental protection certified to the demanding US MIL STD 810G standard.

The unit still relies on Multiple-Echo to provide simple and accurate measurements, with the added benefit of Echo-Echo and Single-Echo using twin crystal probes for extreme corrosion. Echo-Echo for measurements on painted metals but with heavy back wall corrosion / pitting and Single-Echo for measurements on uncoated surfaces with heavy front face and/or back-wall corrosion and attenuative materials such as cast metals or plastics / composites.

Winner of the Red Dot Award: Product Design 2015 (Click for more details)

Cygnus 4+ General Purpose Brochure  Enquire about the Cygnus 4+ General Purpose


  • Multiple-Echo for reliable, accurate through coating measurements
  • Single-Echo and Echo-Echo measuring modes with twin crystal probes for extreme corrosion and back wall pitting
  • A-scan display
  • Manual and automatic gain control
  • MSI™ (Measurement Stability Indicator) used in Single-Echo and Echo-Echo measurement modes
  • Simple linear data logging
  • Large bright colour LCD screen with back light
  • Deep-coat mode, measure through coatings up to 20 mm thick
  • Wrist mountable
  • Min/max measurement limit functions with visual and vibrate alert
  • Intuitive easy to use menu
  • Extremely rugged enclosure – shock and impact to US MIL STD 810G
  • Environmental sealing to IP67 – US MIL STD 810G
  • Cygnus echo strength bars to assist quick measurements
  • Buttons integral with the TPE moulding and designed for minimum 100,000 depressions.

Data Logging Key Features:

  • Versatile data logging which allows measurements and A-scans to be saved
  • 5,000 measurement points (including A-scan) per record
  • Records are saved to a removable SD card
  • Selectable auto-log feature
  • Records easily transferred via gauge USB port to CygLink software where they can be exported to a .CSV file or a PDF report.


Cygnus Probes and Cables

Cygnus Stainless Steel INOX Probes (Single Crystal Probes)

The INOX probes have an updated ergonomic design and easier to read frequency, identification and serial number. All frequencies of INOX probes have a black face and a colour coding system to identify probe frequencies. Used in Multiple-Echo mode, these probes require no zeroing, have a high linear accuracy, are ideal for general thickness gauging, for use on pipes and have replaceable wear membrane for long life.

Cygnus Stainless Steel INOX Probes (Twin Crystal Probes)

Used in Echo-Echo and Single-Echo modes for a focussed ultrasound beam for improved measurability on extreme back wall corrosion and pitting.

Cygnus Cables

Using standard industry connectors the probe lead uses a custom made over moulded cable that offers superior flexibility and resistance to oils and ultraviolet light. The cable will not stiffen after exposure to ultraviolet light.

Flexible Handling

Along with the wrist and neck straps supplied in the kit there is also an optional belt clip, offering a range of flexible handling solutions for all types of applications.

Product Enquiry: Cygnus 4+ General Purpose

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Materials Sound velocities between 1000 - 9000 m/s - covers virtually all common engineering materials
Accuracy ±0.1 mm or 0.1% of thickness measurement, whichever is greatest, when calibrated in accordance with Cygnus Instruments calibration procedure
Resolution Multiple-Echo mode - 0.1 mm or 0.05 mm
Single-Echo and Echo-Echo modes - 0.01 mm
Probes Single crystal probes:
  • 6 mm - 5 MHz (S5A)
  • 13 mm - 2.25 MHz (S2C (standard)), 3.5 MHz (S3C) or 5 MHz (S5C)
  • 19 mm - 2.25 MHz (S2D)
Twin crystal probes:
  • 5 mm - 7.5 MHz (T7A)
  • 8 mm - 5 MHz (T5B (standard))
  • 13 mm - 2 MHz (T2C (for attenuative materials such as cast metals, plastics and composites))
Measurement Range in Steel Single crystal probes in Multiple-Echo:
  • 3 - 250 mm with 2.25 MHz probe (S2C/D)
  • 2 - 150 mm with 3.5 MHz probe (S3C)
  • 1 - 50 mm with 5 MHz probe (S5C/A)
Twin crystal probes in Single-Echo:
  • 2.5 - 250 mm with 2 MHz probe (T2C)
  • 1 - 200 mm with 5 MHz probe (T5B)
  • 0.8 - 50 mm with 7.5 MHz probe (T7A)
Twin crystal probes in Echo-Echo:
  • 5 - 50 mm with 2 MHz probe (T2C)
  • 4 - 50 mm with 5 MHz probe (T5B)
  • 3 - 25 mm with 7.5 MHz probe (T7A)
Connector Twin Lemo 00
Power 3 x AA batteries
Battery Life 10 hours minimum
Electronics Dual channel pulser
Display 2.4" quarter VGA LCD
Size 132 x 82 x 34 mm
Weight 300 grams (inc. batteries)
Operating Temp. -10°C to 50°C
Data Logging Capacity up to 5000 points including A-scans
Computer Software CygLink allows remote logging and viewing of A-scan graphs.
Survey and report generation to PDF file.
Data can be exported as a .csv file.
Graphic analysis of data and statistical calculations.
Designed for Windows 7 and Windows 8.
Environmental Rating IP67 (dust tight and immersion - 1 metre for 30 mins)
Explosive Atmosphere: Safe operation as defined by Class I, Division 2, Group D, as found in the National Fire Protection Association Code (NFPA 70), Article 500, and tested using MIL STD 810G Method 511.5, Procedure I
MIL STD 810G Method 501.6 (high temp +55°C)
MIL STD 810G Method 502.6 (low temp -20°C)
MIL STD 810G Method 507.6 (humidity 95%)
MIL STD 810G Method 512.6 (immersion - 1 metre for 30 mins)
Shock and Impact MIL STD 810G Method 514.7 (vibration - 1 hour each axis)
MIL STD 810G Method 516.7 (shock 20g - 11ms half sine shock pulse, 40g 11ms in each axis)
MIL STD 810G Method 516.7 (26 drops - transit drop 1.22 m)
Compliance CE, British Standard BS EN 15317:2013
Environmental RoHS, WEEE compliant
Warranty 3 years on gauge and 6 months on probe

Kit Content

Cygnus 4PLUS UT gauge; padded carry case; operating manual; adjustable neck strap and loops; wrist strap; accessory pouch; spare membranes; surface and membrane couplant; test block; 3 x AA batteries; mini USB - USB cable and instruction manual optional Krusell® belt clip.

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Product Reviews

  • 24 May 2017
    Rated 5 out of 5
    We approached Cygnus in late 2016 as a result of discovering areas of corrosion in our vessel Lord Nelson in an area specific to the design allowing for disabled access - the watertraps. These areas act to prevent the ingress of water into the vessel given that we can't have door sills due to the flat sill required for wheelchairs.

    Given the age of Lord Nelson, now over 30 years old, it was agreed that to have our own NDT test instrument, while not negating the need for formal Lloyds' testing, would allow us to keep a check on corrosion and give us a level of confidence as and when areas were discovered. Cygnus kindly offered advice and supplied a Cygnus 4+ Ultrasonic Multi-Mode Thickness Gauge kit including both single and dual crystal probes.

    Despite our own relative inexperience in such testing, the results we obtained were confirmed by professional spot testing and proved easy to achieve, the device being simple to calibrate and use, with both probe types.
  • 02 December 2015
    Rated 5 out of 5
    We tested the New Cygnus UTM Instruments 2+ and 4+ using single & twin crystals probes.

    Tests carried out in our premises and in real working conditions on a 15 years old cargo ship of 10.000 M.Tns.

    In our premises we used the following samples, which have been obtained from ships’ cropped plates and we use them in our premises for practice purposes.

    1.New Coated Steel Plate 10.0 mm.
    2.Extremely corroded on both sides Steel Plate, with thickness variation from 4.6 mm to 9.7 mm. Taken gaugings were verified with Outside Callipers.
    3.Gray Cast 12.0 mm.
    4.Aluminium 6.0 mm.

    On the Cargo Ship we focused our tests on the non-coated Inner Bottom Plating of 16.0 mm original thickness.
    We got about 100 gaugings which varied between 15.8 mm to 14.4 mm.

    All readings, in both tests, were obtained instantly and it should be mention that the new measuring experience with MSI System gave to us a real confidence that the reading we see is the real remaining thickness on that spot.

    Apart the user-friendly, high analysis coloured LCD screen and the very easy menu we consider quite important to mention that once we took the instrument in our hands we got an immediate impression of the unit being very rugged. Its tight case together with the strong cable and its twin lemo locking connector allow the operator to focus only to the gauging without worrying at all about the machine.

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