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Dakota Ultrasonics MiniMax

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Dakota Ultrasonics MiniMax
Product Description
Additional Info
Product Literature

MiniMax Bolt Tension Monitor

The MINI-MAX Ultrasonic Bolt Tension Monitor defines state of the art in the measurement of the actual elongation produced by tightening a threaded fastener. MINI-MAX can measure the elongation very accurately in fasteners of virtually any material from 1/2 inch to 4 feet in length. The measurement is achieved by determining  the change in the transit time of an ultrasonic shock wave along the length of the fastener, as the fastener is tightened by any method.  The on-board microcomputer automatically interprets this time measurement to display the time(nanoseconds), elongation, load, stress or strain from stretching a fastener.  Through the use of high speed digital signal processing and automated diagnostics, the MINI-MAX minimizes the requirement for extensive operator training.  With built in data recordation and reporting through an RS232 interface, the MNI-MAX offers an easy to use and reliable solution to the most difficult bolting problem.


  • The first cost effective ultrasonic solution available on the market.
  • Effectively monitors your bolts during periodic shutdowns over the service life of the fastener.
  • Visually compares the unloaded to the loaded waveform.
  • Measurement quanities – Time (nanoseconds), Elongation, Load, Stress and Percent Strain.
  • Display Options – RF, Rectified and Large Digits with Limits Bar.
  • Display Resolution – 1/8″ VGA 240 x 160 pixels.
  • Stores 8000 readings and waveforms in multiple groups.
  • Built-in Linear regression or vector, for optimizing load measurements.
  • The Auto Set feature automatically optimizes detection and adjusts display.
  • Hi/Lo alarm tolerance limits work in conjunction with the data port and external pump shut-off device.


Physical Attributes:

  • Size:
    • Width: (2.5in/ 63.5 mm)
    • Height: (6.5 in/ 165 mm)
    • Depth: (1.24 in/ 31.5 mm)
  • Weight:
    13.5 ounces (with batteries).
  • Keyboard:
    Membrane switch pad with twelve tactile keys.
  • Operating Temperature:
    14 to 140F (-10C to 60C)
  • Case:
    Extruded aluminum body with nickel-plated aluminum end caps (gasket sealed).
  • Data Output:
    Bi-directional RS232 serial port. Windows® PC interface software.
  • Display:
    1/8in VGA grayscale display (240 x 160 pixels). Viewable area 2.4 x 1.8in (62 x 45.7mm). EL backlit (on/off/auto).


Ultrasonic Specification Measurements:

  • Modes:
    • Pulse-Echo: (standard)
    • Pulse-Echo w/Gate: (fine adjust)
  • Pulser:
    Square wave pulser with adjustable pulse width (spike, thin and wide).
  • Receiver:
    Manual or Auto Set gain control with 40dB range.
  • Timing:
    10 bit 250 MHz digitizer.



  • 2 year limited


Power Source:

  • Three 1.5V alkaline or 1.2V NiCad AA cells
  • Typically operates for 150 hours on alkaline and 100 hours on NiCad (charger not included).
  • Auto power off, if idle for 5 min.
  • Battery status icon



  • Range: From 1″ to 48″ (25.4mm to 122cm) bolts.
  • Time – Nanoseconds.
  • Elongation – Change in length (inches/millimeters).
  • Load – Force load applied (pounds kIP or kN Kilonewtons).
  • Stress – Force for unit area stress applied (pounds kPSI or megapascals MPa).
  • Strain % – percentage strain applied (inches per inch or millimeters per millimeter).
  • Resolution:
    +/- .00001 inches (0.0001 mm)
  • Velocity Range:
    .0492 to .3936 in/ms (1250 to 9999 meters/sec)
  • Fixed, Single and Two point zero calibration options.
  • Select bolt material types from a preset or custom list.
  • Units:
    English & Metric / Fahrenheit & Centigrade.



  • A-Scan – Rectified +/- (half wave view) or RF (full waveform view).
  • Large Digits – Display and toggle between nanoseconds, elongation, load, stress and strain.
    Digit Height: 0.400 in (10mm).
  • Limits Bar(alarm limits) - Set High & Low alarm limits for displaying an acceptable tolerance range.
  • Repeatability Bar Graph – Bar graph indicates stability of measurement.


Data Logger (Internal)

  • Total of 8,000 readings in multiple bolt groups. Stores both waveform views, nanoseconds, elongation, load, stress and strain for each reading.



  • 16 megabit non-volatile ram Transducer


Transducer Types:

  • Single Element (1 to 10 MHz & 1/8″ to 1″diameters)
  • Locking quick disconnect “00″ LEMO connectors
  • Standard 10 foot cable
  • Custom transducers and cable lengths available on request.
  • Temperature probe for automatic temperature compensation.



  • Setups: 64 custom user defined setups. Factory setups can also be edited by the user.
  • Gate: The Gate is used to fine adjust where the detection point occurs.
  • Alarm Limits: Set high and low tolerances with audible beeper, viewable scan bar and visual LEDs.
  • Auto Set: Locates the detection signal, optimizes the gain setting and adjusts the overall display, to show the waveform and detection point automatically.
  • Field Calibration:
    • Vector & linear regression
    • Certification
    • Factory calibration traceable to national standards.

Standard MiniMax Kit Includes: MiniMax, 3 AA Batteries, 4oz Bottle of Couplant. RS232 Transfer Cable Lemo to DB9, Carrying Case, 10' Lemo to Microdot Transfer Cable, Windows Utility Software, Operation Manual and Certification.

**Transducer not Included

Please Note: To add an item/multiple items to your shopping cart, check the corresponding box/boxes and click "Add To Cart"
Part #
Product Name Part # Price Qty
MiniMax Kit without Temperature Connector – External temperature source used, or user will be measuring fasteners one time only. UT-DU-Z-156-0001 $3,025.00
MiniMax Kit with Temperature Connector – Included only with the purchase of a temperature sensor # A156-8001. UT-DU-Z-156-0002 $3,025.00
Single Probe, Magnetic, 5 MHz, 1/4", Microdot, Top Mounted, T-702-2405 UT-DU-T-702-2405 $765.00
Single Probe, 2.25 MHz, 1/2", Microdot, Top Mounted, T-5043-1855 UT-DU-T-5043-1855 $290.00
Temperature Probe UT-DU-A-156-8001 $525.00
3" & 6" Steel Calibration Bars UT-DU-X-000-0010 $575.00