Testing regimes demand careful consideration

Testing is a very important - and sometimes under appreciated - aspect of bringing a new product to market that needs careful consideration, notes Paul Beardsworth, HBM’s Sales Manager UK & Ireland:

Imagine you’ve just arrived at the most fantastic idea that could highlight the sheer brilliance of British engineering and manufacturing with its stellar sales performance. Among the many challenges before it reaches market is to thoroughly test your various concepts. This can ensure that desired performance criteria and operational functionality is met while the necessary visual impression is created.

There are a number of things that need to be considered before embarking on a testing regime. In broad terms these aspects break down into three broad-based areas: measuring any variables, accurately capturing the measurements, and finally, analysing the data so that coherent feedback can be given enabling design engineers to identify alternative solutions.

Measuring the different variables requires careful consideration about what information is needed and how that can best be measured. For example, sensors might be needed to measure a wide range of temperatures from ambient conditions that can subsequently be compared with the range of operational temperatures at various points throughout the design.

Strain gauges of various designs might be required to measure different levels of strain through the design and its component parts so that structural integrity can be assured. Other measurements that can impact on a design’s performance include torque, pressure, displacement and force.

When specifying sensors for any type of measurement the possible upper and lower limits of the likely measured range need to be considered as different sensors can perform differently. The rate at which measurements might change might also be worth considering; you need the most appropriate sensors for your particular testing regime.

In some cases it may be possible to specify dual-purpose sensors to increase testing flexibility. Another factor is the ease with which any sensors can be fitted and used. For example, all of HBM’s sensors are TEDs (Transducer Electronic Data Sheet) equipped to simplify installation and facilitate communication with the data acquisition (DAQ) system.

To accurately capture all of the measured data for subsequent analysis demands a DAQ system that is capable of operating under specified test conditions and that lends itself to easily transferring data to analysis software or - where suitable - providing a simplified initial assessment to quickly identify areas that might benefit from additional rigorous testing.

For most measurement tasks a universal and highly flexible DAQ such as HBM’s QuantumX and MGCplus provide suitable solid support. QuantumX is a modular device with various specialised units within the family to ensure that virtually every measurement task can be successfully undertaken.

These include, for example, the CX22W that is primarily for mobile or stationary uses as a stand-alone device or the 8-channel universal amplifier, MX840A. Every model in the range provides 24-bit A/D (analogue to digital) converter on each channel as well as supporting for all existing transducer technologies.

Another DAQ system suitable for many testing regimes is HBM’s MGCplus although this is best suited to applications such as laboratory, test stand, experimental stress analysis and durability testing rather than field-testing.

Specialised DAQ devices might be needed for some testing regimes. You might, for example, need to gather a lot of data from a structure such as a bridge where the data is not changing rapidly and needs to be gathered from a widely distributed array of sensors.

For such applications a device like HBM’s CANhead can simplify the data gathering exercise.

The advantage of CANhead is that it is a distributed amplifier system removing the need for long confusing cabling. Cables from the measuring point to the CANhead module are short - saving time, effort, and cost while simplifying the management of vast numbers of measuring points in a test.

By contrast, it might be necessary to test a component or sub-assembly to destruction and this might require a wide array of strain gauges and other sensors to detect and isolate key critical areas of failure. To meet these needs, HBM has developed the Genesis HighSpeed family with sample rates of up to 100 MS/s per channel to where mid- and high-channel data counts are needed. Genesis HighSpeed is a modular platform so that configuration for the precise needs of any application is simplified.

Often mobile testing, in particular, needs to be undertaken in very tough environments and HBM has developed its SoMat eDAQ and eDAQ-lite products to meet this need. For example, the SoMat eDAQ is a sealed stand-alone data acquisition system for testing in the harshest of environments with leading-edge signal conditioning and the capacity to perform a broad range of on-board data processing.

Hundreds of synchronous channels are possible in a single system, with virtually limitless channel counts when networking these Ethernet-based systems.

Equally, your product may be need testing where larger measurement systems would be prohibitive because they are too complex and expensive. For these situations HBM has developed the espressoDAQ series of USB-based measuring amplifiers that reliably acquire virtually all measured quantities. The modules offer very high quality and performance capability, such as carrier frequency technology and A/D converter with a resolution of 24 bit.

Finally, to analyse the results, HBM offers its powerful catman® software for configuring, visualizing and analysing measurement and data acquisition systems.

Alternatively, HBM’s Perception software processes huge amounts of data swiftly and reliably making it ideal for high-speed data acquisition: up to 10 gigabytes of data can be visualized in 10 seconds.

Similarly GlyphXE is innovative and powerful analysis software that handles vast amounts of data from acquisition through to the final test report while HBM’s nCode software is optimised for test and design analysis, fatigue analysis and web-based analysis and collaboration.

There is one other consideration that is often overlooked; sourcing the equipment needed for the wide range of tasks required.

One way is to buy equipment on an ad hoc basis. While it might be possible to realise marginal cost savings with this approach it does mean working with a number of different suppliers and there can be challenges with different equipment communicating with each other.

Alternatively, it might be more sensible to source equipment from a single manufacturer, such as HBM, that can supply the complete measuring chain providing greater reassurance of data integrity.