Industrial Displays for Hazardous Areas
What is a Class I, Div. 1 industrial display? It’s a common question asked to our technical support experts. Another variation: What choices do I have for HMI visualization and machine control in a Division 1 area? One key element in answering this question correctly is to know if this is just a monitor or if there's a need for PC computing power.
There a few simple ways to get the desired monitor or HMI interface into the hazardous area. The most cost-effective solution is a small purged enclosure and a hazardous-rated LCD monitor. If a touchscreen is required, then it would also require an intrinsically safe touchscreen.
To explain in a bit more detail, a Class I, Div. 1 industrial display is defined as a visualization solution intended for use in hazardous "classified" locations. Class I, Div. 1 industrial displays can be used for monitoring processes in hazardous locations. This could be just a monitor with a DVI or VGA connection to a PC or server in a safe area, or a stand-alone panel PC or Ethernet monitor operating in the hazardous location.
Since a Division 1 location contains ignition-capable levels of gas-air mixtures on a regular basis, an industrial display intended for these areas must be protected by a suitable protection method.
The acceptable methods used in areas classified for North American Divisions are:
- Intrinsic safety
- Purge and pressurization
Due to the power requirements of LCDs, PCs, and other associated electronics, intrinsic safety is not suitable for these hazardous areas, and large explosion-proof enclosures are typically very bulky and expensive. Furthermore, explosion-proof construction would result in difficult design requirements for touchscreens, large windows, and keyboards.
The HMI and monitor solutions for Class I, Div. 1 are best suited for the protection method purge & pressurization, which protects the internal electronics from ignition hazards by providing positive pressure inside the enclosure with air or some other inert gas. This prevents the explosive gas from entering the enclosure and allows it to operate within the Division 1 hazardous location.
To learn more, download our VisuNet Industrial Systems solutions brochure that highlights many of our industrial and hazardous-rated HMI solutions.