Dots make the difference

“Industrial Process and Control Engineers want something very different when they are making electrical measurements from the average commercial or domestic electrical contractor. Because they are endeavouring to predict the life span of electrical equipment such as motors and relays, they need more and better information” says Brendan Beaver, UK manager of Metrel® Ltd, the innovative provider of electrical test solutions.

“Dot matrix touch-activated displays have revolutionised the portable electronic instrumentation by permitting large amounts of information to be displayed simultaneously on a high resolution screen.”

“Until recently test measurements made on installations were displayed on custom produced LCD screens. The advantage of using these screens on multi-function testers, was that they were relatively inexpensive and tough. The disadvantage was that they are have limited amount of space to display useful information and they are totally inflexible. Should the regulations change and require a new test, the firmware in the instrument can change, but the screens cannot display the result.”

“Metrel pioneered the use of dot matrix displays, realising their flexibility both for displaying information to the user and their potential for change, making updating products easier and keeping customers happy.”

Initially Metrel introduced mono-chrome screens. Customers, not just in Britain but in Australia and New Zealand, took to the idea quickly as the testers did not just display results but other useful information like test parameters expressed in simple English.

Even more exciting, help screens were also available to assist when the memory failed. Even engineers welcome a reminder of the conventional measurement connections.

The simplest and most obvious example of flexibity of these dot matrix products is that of language, in the UK the testers display in English, in Sweden Swedish. And one might think obvious, but few if any quality instrument manufacturers can manage this in a single tester.

With the arrival of tough full-colour, dot matrix, touch screens testing has never been so good!

Tests are clearly colour coded to make it easier for the operator. The parameters for the tests can be shown throughout the test, to reduce the risk of mistakes such as testing a Type AC RCD as a Type A because a tiny icon was not noticed. The results for a sequence of tests, such as the AUTO RCD test, can be displayed on a single screen with a clear pass or fail indication, so the numbers can be quickly identified and saved on-board; avoiding the slow scrolling process that normally follows such a test.

Let’s look a bit closer at the flexibility Metrel instruments like the industrial engineers’ favourite multi-function tester MI3155 gain from the unique screens. Back in 2015 Amendment 3 of the 17th Edition of the wiring regulations included mention of the measurement of voltage drop and of the assessment of power quality in its appendix.

In response to the potential change in the Regulation requirements; having confirmed the hardware could supply the measurements required, Metrel modified the instrument firmware introducing a voltage drop measurement and for the first time on an instrument in this class a suite of power quality measurements such as THD to the 12th harmonic. Metrel’s policy is to allow users to up-grade their own firmware, direct from the Metrel website themselves.

The easy-view graphics and full QWERTY keyboard makes the use of on-board memory a realistic proposition for the first time. By allowing the engineer to produce schematics of the system under test, and saving the test results and the test parameters to the object on the system that represents the point where the results were measured.

It makes using a downloading tester the easy option when working in confined or awkward locations.

For more information contact Brendan Beaver at Metrel UK Ltd. on 01924 245000 or or visit

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