Displaying important real-time information clearly in hazardous environments
16 June 2021
Being aware of critical process variables is important in most manufacturing environments. In the past, measurements were limited to true physical variables, such as pressure, temperature, weight, and speed.
ExnR display being tested for offshore installation in the Gulf of Oman.
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Nowadays, many modern production processes also rely on teams being aware of computed variables, such as OEE, Takt time, Down time, Actual Total versus Target etc. This awareness allows teams to respond quickly to events which could affect the plant's ability to achieve target performance. But the team needs to be able to see the information in order to act upon it.
Most existing display systems have limited viewing distance
Most industrial PCs, annunciators and touch screens for hazardous areas have a practical reading distance limit of a few metres. This means that operators who need to know an important value must walk over to a display, which could be an appreciable distance away from their working position.
If they are busy, they may not have time to go to the display, so could miss important changes in process performance. This is becoming increasingly important as plants reduce workforce size; fewer team members are available to access the data, so the chance of missing important changes becomes even higher, if data is not easily accessible.
Making data clearly visible over long distances
Typical 6-digit numeric ExnR rated displays, awaiting installation.
Display technology for hazardous areas has advanced greatly in the past few years, with the introduction by various manufacturers of Atex En nR rated large digital displays and large message displays.
These large format displays can be mounted in prominent locations and have a choice of character heights to suit viewing distances up to 200 metres.
They are often suitable for indoor and outdoor use, with a choice of colours, thanks to the latest high contrast, high brightness LED display technology.
Flexibility of signal types
Recent versions of Atex EXnR large digital and text displays can accept most industrial sensors directly. They tend to be fully self-contained, which makes installation, commissioning and maintenance simple and economical.
For example, most displays only need power and a sensor in order to display weight, total, speed, takt, temperature, time etc.
They can also act as slave displays, if preferred, accepting RS485, TCP/IP, Ethernet/IP, Profibus etc., allowing safety information and other important news items to be shared with the staff.
Modular systems allow multiple displays in one ATEX enclosure
Graham Laming, London Electronics
Every process is different, with different key requirements, so displays which can be configured to each installation's needs are becoming more readily available and more affordable.
Bright, clearly visible large displays attract attention
By their very nature, large format ATEX displays are intended to be attention-grabbing.
They ensure staff know what is happening on the plant so that they can act quickly in response to critical process changes.
Whilst ATEX rated large displays were something of a rarity in the past, mainly being custom-built and quite costly, the current state of technology means that almost any process in an ATEX Zone 2 environment can benefit from readily available real-time large display technology.
The benefits help to ensure that the process operates to peak efficiency, maximising profitability and competitiveness for the owner.
About the author:
Graham Laming is Technical Marketing Manager at London Electronics, a designer and manufacturer of digital panel meters, large digital displays, electronic text displays and custom factory efficiency monitoring systems. Graham has been in his current role for 29 years, designing and managing new product development. He is the patent holder for the company’s latest core instrumentation technology and a qualified Electronics Design Engineer, member of the IET, and Fellow of the Chartered Institute of Marketing.
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