DJB Instruments

DJB Instruments UK Ltd has been manufacturing accelerometers, cables, instrumentation and accessories for over 40 years. We design, manufacture, assemble, test and calibrate every part of our products all in-house. We export all over the world via a network of distributors

We have been a British leader and manufacturer for over 40 years, proudly achieving a substantial range of quality accelerometers and vibration testing equipment whilst maintaining the unique Konic Shear design introduced by the company’s founder Don Birchall to better aid your needs.

We all have a care for the work we do at DJB, proud of its history and keen for its future. This is reflected in the products we have available and the services provided to support you in your testing needs all the way through your process. The company’s main focus is to manufacture piezoelectric accelerometers (IEPE and Charge), dynamic pressure transducers and analogue signal processing instrumentation.

Download Complete Technical Reference & Product Guide

Monoaxial Charge Output
  • Miniature Charge Accelerometers
  • General Purpose Charge Accelerometers
  • High Sensitivity Charge Accelerometers
  • Seismic / Micro G Charge Accelerometers
  • Industrial Charge Accelerometers
Monoaxial IEPE
  • Miniature IEPE Accelerometers
  • General Purpose IEPE Accelerometers
  • High Sensitivity IEPE Accelerometers
  • Seismic Micro G IEPE Accelerometers
  • Calibration Reference IEPE Accelerometer
  • High Shock IEPE Accelerometers
  • Industrial IEPE Accelerometers
  • DJB Impedance Head
  • Low Cost Industrial IEPE Accelerometers
Triaxial Charge Output
  • Miniature Triaxial Charge Accelerometers
  • General Purpose Triaxial Charge Accelerometers
  • High Temperature Triaxial Charge Accelerometers
Triaxial IEPE
  • Miniature Triaxial IEPE Accelerometers
  • General Purpose Triaxial IEPE Accelerometers
  • High Temperature Triaxial IEPE Accelerometers
High Shock

Voltage Output - IEPE Accelerometers feature an integrated circuit in the form of a built in charge to voltage converter (QVC), requiring minimal instrumentation to connect the accelerometer to a data acquisition system. The hybrid QVCs implemented in our IEPE accelerometers generate a low impedance, noise immune voltage proportional to the input charge. These hybrid QVCs allow for any kind of cable to be used with the Accelerometer. The high shock range of IEPE excels feature built in filtering at 10,000g and above to reduce high frequency ringing, the A/16X range can be used with our range of triaxial mounting blocks FB1 and FB2 for high shock triaxial measurements. Alternatively our A/130/V.1 triaxial accel with built in sensors can be used up to 5000g testing where installations are more restricted, this can also be provided with a mounting plate to allow for mounting on a curved or oddly shaped test surface A/130.Shim

  • High Shock Monoaxial IEPE Accelerometers
High Temperature

A unique device specifically developed for exhaust and turbo charger testing where surface temperatures can exceed 900°C. As the only fully integrated device on the market it offers unrivalled reliability and repeatability under the most extreme conditions. Using a simple water pump (usually a car windscreen washer pump) requiring just 0.5ltr/min flow the operation is both simple and effective.

With no reduction in operating temperature, even using the IEPE voltage output version, DJB leads the world in this application.

  • Triaxial Charge High Temperature Accelerometers
  • Triaxial IEPE High Temperature Accelerometers
DC MEMS Accelerometers

The AM range of accelerometers are MEMS (micro electro mechanical system) DC response voltage output devices for testing at low frequency vibration measurement from DC (0Hz) and above. They are single axis variable capacitance design and are available with a 2m integral cable fitted with a 7pin connector to suit the DJB DCM-03 MEMS signal conditioning unit or alternatively as bare wires.

Ideally suited to low frequency vibration applications including low level vibration where high sensitivity is required.
Due to their ability to measure DC response they can also be used to measure constant gravity application.

  • DC MEMS Monoaxial Accelerometers
  • DC MEMS Biaxial Accelerometers
  • DC MEMS Triaxial Accelerometer
Seismic, Micro G

Seismic accelerometers are generally much bigger and heavier than other test and measurement accelerometers. This is due to the much higher quantity of piezoelectric material and the large mass material required to create the high output (typically 10V/g or 9000pC/g) which allows for micro ‘g’ measurements. They are also limited on their higher frequency capability, usually limited to 500Hz to 1kHz. With a typical peak measurement range of just 0.5g their use is restricted to typical seismic applications.

  • Monoaxial Charge Seismic Accelerometers
  • Monoaxial IEPE Seismic Accelerometers
Industrial Accelerometers
  • Charge Output Industrial Accelerometers
  • Voltage Output Industrial IEPE Accelerometers
  • Low Cost Monoaxial Piezoelectric Accelerometers
Low Cost

The A/140 range of accelerometers are rugged low cost industrial units for use in a wide variety of applications including wind turbines, steel mills, oil pipelines, trains, machine monitoring, bearing analysis and many others. The A/140 series is manufactured from corrosion resistant stainless steel which is fully integrally sealed against environmental effects, with a Military style 2 pin Mil-C-5015 type connector side mounted it offers considerable benefits whilst ensuring a minimal cost per item.

With lower mass than many similar industrial accelerometers and industry standard ¼-28 UNF mounting screw which is supplied, it is a direct replacement for current devices on the market.

  • Low Cost IEPE Accelerometers
Piezoelectric Pressure Sensors

Dynamic pressure transducers based upon piezoceramics allow deflection of acoustic type phenomena including turbulence and cavitation associated with fluid flow and are produced in two basic packages.

For applications involving significant background vibration, accelerometer compensation may be included.

The high sensitivity and linearity of these devices allow detection of accoustic levels as low as 70dBA superimposed upon pressure fields up to 500bar.

DJB’s range of dynamic pressure transducers offer solutions for high temperature applications as well as vibration compensated options, full signal conditioning equipment is also available.

AF Impedance Head

The AF/50/5 and AF/100/10 IEPE Impedance heads integrates an IEPE accelerometer and force sensor into one device to measure dynamic acceleration and force simultaneously.

The AF impedance head is manufactured in stainless steel, has a mass of 30 grams and an operating temperature range of -40 to +121°C (-40 to +249°F). IEPE sensitivity options including 5mV/N and 10mV/N for measuring force and 50mV/g and 100mV/g for acceleration dependent on your requirements.

With a low impedance voltage mode and an effective anti-jamming facility the AF impedance head is ideal for use in modal and structural analysis. It can be attached to an input stinger that is itself driven by a modal shaker and also attached to the test structure via the two M5 tapped mounting holes. The use of IEPE sensors provides accurate measurement of applied forces over a wide bandwidth providing extensive excitation range for Modal testing, unlike other strain gauge sensors which are used for static and quasi-static environments.

As with all IEPE sensors, setup is easy and the AF can be connected directly to a data acquisition and analysis system equipped with IEPE signal conditioning within the range of 2-10mA and 18-28VDC. Cables of any length can also be supplied to suit all test set ups and the calibration certification supplied provides National traceability.

IEPE Signal Conditioning

IEPE Signal Conditioning and Voltage Source Amplifiers

MEMS VC 3 Channel Signal Conditioning

The DCM-03 MEMS DC signal conditioner is for use with DJB’s range of AM, AMB and AMT variable capacitance MEMS accelerometers. The unit has 3 channels and can be used with three single axis capacitive accelerometers or one triaxial capacitive accelerometer. Offering a wide range of features in a compact and powerful unit the DCM-03 is the perfect addition to your low frequency testing system.

Impact Hammers

The IH range of impact hammers offer a range of 7 hammers ranging from 50N to 50000N.

The hammers all feature IEPE integrated electronics force transducers for simple connection - direct to analysis front ends or to voltage source instrumentation.

The IH series IEPE impact hammer range features a rugged force sensor that is integrated into the hammers striking surface.The force sensor serves to provide a measurement of the amplitude of the energy stimulus that is imparted to a test object. A variety of tips supplied with each hammer permit the energy content of the force impulse to be tailored to suit the requirements of the item under test. Using multi-channel data acquisition and analysis software, the test engineer is able to ascertain a variety of mechanical properties leading to an understanding of an objects structural behaviour. Items analysed can include resonance detection, mode shapes, transfer characteristics, and structural health, such as crack and fatigue detection.

IH series impact hammers can be applied for Structure Health Testing, Resonance Determination, Modal Analysis etc.used in association with DJB’s wide range of accelerometers full response data can be captured during impact testing.

All IH Impact Hammers come in their own case with cables and tips.

Junction Box

DJB Instruments UK Ltd provide a fully custom service for the design, build and testing of junction boxes for the use in vibration test facilities.

Junction boxes also referred to as patch panels are often used to provide a connection between vibration control systems or data acquisition systems located in a remote control room or next door safety area and the test chamber itself which may contain an electromagnetic or hydraulic shaker or other noisy or potentially dangerous test rig.

From many years of experience we have found that no two customer requirements are quite the same due to connector types, channel count, cable lengths, box requirements, labelling etc. so we create a custom drawing and configuration plan for every customer. We can provide a wide range of bulkhead mounted sockets fitted into the junction box (10/32 microdot and BNC
are the most common) connected via low noise or non low noise cable of any length via a cable gland and cable sleeving to breakout connectors of almost any sort (BNC plugs are the most common selection).

The junction boxes can be flanged or with mounting holes, painted or powder coated and can include engraved labelling for channel numbers.

Handheld Vibration Meters

The VS1 is a compact, rechargeable, handheld Vibration Meter designed to conform to ISO10816-3 and operates with a constant current IEPE accelerometer providing accurate vibration measurement.

Features:

  • Storage of up to 100 time-stamped readings.
  • Vibrant colour LCD Display.
  • Rechargeable Lithium-ion battery with worldwide charger.
  • RMS, peak, peak-peak, crest factor readings in acceleration, velocity or displacement modes.
  • Bearing condition mode (acceleration and velocity).
  • Industrial Rubber Case.
  • Adaptive amplifier for high accuracy.
  • AC output.
  • Audio output for listening to vibration directly.
Accelerometer Calibrators

The VC-01 Handheld Calibrator is a low cost reference accelerometer device that allows the user to quickly check the response of accelerometers at a known fixed frequency and level. Ideal for use in the field or in a lab. Its simple one button operation ensures all the user needs to do is fix the test accelerometer to the top of the calibrator either using the supplied stud or via adhesive/petro wax and press the button. The output can be monitored on any signal analyzer or scope and the level checked against the known excitation level.

Features:

  • Battery powered with auto shutdown
  • Lightweight, simple one button operation
  • Stud adaptor included
  • Rugged black anodized aluminum case
  • Battery level indicator
Modular Signal Conditioning Systems

Data derivied from Piezoelectric Accelerometers is in the form of electrical charges proportional to the mass applied, and requires further processing in order to extract specific information. The widely used IEPE Accelerometer features an inbuilt QVC - converting the charge to a voltage prior to signal transmission. Where the signal is strong enough, minimal instrumentation is required to interface with the accelerometer. However, in some cases it will be neccesary to amplify the signal with a voltage source amplifier.

IEPE Accelerometers are not suitable for some applications, and a charge output accelerometer will be required. Charge output accelerometers are able to withstand higher temperatures, and are generally more rugged, with the downside being the requirement for extra instrumentation. DJB's 04 Series provides a comprehensive range of instrumentation covering most applications, conveniently housed within module housings, with integrated power supplys.

The 04 System features Accelerometer signal processing, and signal conditioning equipment. The signals from the accelerometer can either be displayed on a screen housed within the system, or connected with front end hardware. Signals from the accelerometer can also be converted to displacement and velocity with high accuracy analogue modules.

IEPE Sensor Simulator

The 8401 installs in place of an IEPE accelerometer (or other sensor) and accepts signals from a voltage function generator. This allows the user to verify signal conditioning settings and cable integrity, the 8401 uses the power from the IEPE signal conditioning to complete the checks.

Features"

  • Input Voltage: ±5V
  • Output Bias: 11V ±3VDC
  • Amplitude Linearity: <2%
  • Power Supply: 2 to 20mA / +18 to 28VDC
  • Noise: <40mV
  • Size: 60mm x 26mm x 60mm
  • Mass: 120gms
Connectors & Joiners

Connectors and cabling are typically the weakest part of any measurement system. Thus, choosing the right cable is of critical importance for any test system.

Our range of connectors are available pre-fitted to cable or as loose connectors to fit yourself, we also supply fitting tools and instructions.

For applications requiring cables running over a long distance see our range of line drivers.

DJB Instruments offer a wide range of variations on standard, as well as custom connectors.

  • Microdot
  • TNC
  • E - Epoxy
  • UNF
  • BNC
Cables

It is important to use the correct cable when using accelerometers.
Do you know the difference between low noise and non-low noise cable other than the price? Do you know about triboelectric noise effects?
DJB Instruments hold a huge stock of different cable types and sizes to suit all accelerometers. We make all cables to order and can turnaround urgent orders within 24 hours. We also have a cable repair service with a majority of failures occurring at the connector.

Petro Wax

For use with accelerometers for modal testing or other applications where a temporary installation is required, ease of removal is a considerable benefit when using petro wax however temperature of the unit under test must be considered, petro wax is not recommended for high temperature testing.

Available in 25mm square boxes.

Color — Purple

Magnets & Mounting Blocks

Accelerometer mounting is a critical part of the testing process and one that is most commonly overlooked having little attention paid to it. To maximize data accuracy, the accelerometer must be closely coupled with the test item and a poor mounting method can introduce significant errors into the data, particularly as frequency levels rise. Please see our Mounting Guide for more information on the types of mounting available or feel free to contact us should you need further advise. These mounting blocks can be used with a range of accelerometers for vibration and shock testing, including high shock tests up to 25,000g.