No longer do security providers face the problems that used to be inherent with mechanical hardware such as moving parts becoming fatigued. Electric products don’t wear out. But, today, with electronic, solid-state computer peripherals, they nonetheless still have their issues, albeit new ones.
Moisture, insulation and vibration, among other variables, to say nothing about exposure to caustic materials, can provide false alarms as well as damaged results and other failures.
Other problems include heat dissipation, electrical insulation, shock resistance, chemical protection, environmental influences, enhanced mechanical strength, corrosion protection and the effects of water, gases, dirt and grime. The big question for manufacturers of security equipment, and other electronic instrumentation, is how they can eliminate costly repairs or replacements for their end users and let their integrators avoid annoying service calls.
The results they are seeking for their customers are a lower cost of ownership and a greater return on investment over the lifespan of their access control systems.
Potting: a mature, cost-effective way to protect electronics
Potting is simply the practice of covering a component with a resin to guard against potential environmental threats. Potting protects against water and moisture. It insulates key components electrically. Likewise, potting also defends sensitive printed circuit boards and other critical components from thermal and physical shock, chemical attack and tampering, as well as being a shield that protects intellectual property and consumer information. Using potting is recommended to guard sensitive electronic components from impact, vibration and loose wires. In fact, customers should beware of security products that are not potted.
Although typically black, the potting material can be created in any colour. Many companies prefer a colour that will help them drive brand imaging.
Also, today’s potting is not the nasty material from the past. Potting substances are normally RoHS (Restriction of Hazardous Substances) compliant and do not contain any known carcinogenic components. RoHS Directive 2002/95/EC originated in the European Union and restricts the use of specific hazardous materials which may be found in electrical and electronic products (known as EEE).
The terms ‘potting’ and ‘encapsulation’ are often used interchangeably, but technically, potting refers to a shell or ‘pot’ that is filled with resin which becomes a part of the finished component.
Think about it. When we ‘pot’ a plant, we steady and protect the vulnerable root system. We fill the pot with soil and nutrients to hold it in place. When it comes to electrical components, we do much the same thing. Electronic components are also ‘potted’ in suitable enclosures and with appropriate compounds that not only protect against shock and vibration, but also against the formation of moisture. In this scenario, vulnerable electronic parts are kept from any kind of harm.
This explains why potting should be applied over the entire circuit board. If access is required to sensitive serial ports, such as the debug pins on the rear of the reader, they should, at a minimum, be sealed against weather and not available to any outside elements.
In the potting process, specifically, an electronic assembly is placed inside a mould (i.e., the ‘pot’) which is then filled with an insulating liquid compound that hardens, permanently protecting the assembly. The mould becomes part of the finished article and may provide shielding or heat dissipating functions in addition to acting as a mould.
Another major mistake, simply sealing joints with silicone, is not adequate for a security-oriented product. These joints will fail with time or if placed under pressure. This can occur when the reader is not installed on a flat surface. Potting can be thought of as the first ring of good cybersecurity defence.
How does electronics potting work?
There are other solutions that can get the weather-resistance job done, such as conformal coating, which applies a thin protective coating to an entire circuit board. But, depending on the application, they may be less cost-efficient than potting, and neither conformal coating nor full enclosures can address the issue of trapped hot air and the damage it can do. Thus, potting is often the best and most cost-efficient solution.
Among the advantages of ‘potting’ electronics is that it is a very flexible solution. We can apply potting only to high-risk parts and components, as well as to complete boards and assemblies. Conductivity, electrical and thermal isolation and protection against various environmental conditions and threats can all be met by the many available potting materials.
What does all this mean to security access control hardware managers? Most importantly, install only readers that are fully potted and that do not allow access to the reader’s internal electronics from the unsecured side of the building. An immediate upgrade is recommended for readers that fail to meet this standard.
Such vandal resistant, contactless card readers are ideal for installations where more durability is required than with a standard reader. They are becoming big hits at schools, universities, correctional institutions, housing authorities, factories, hospitals and other locales where RFID proximity and smart card readers can take a beating.
The impact of the added vandal resistance that potting provides cannot be underestimated. Essentially, potting helps in making a reader, especially one installed on the unprotected side of a door, more tamper resistant. And, after all, that is where readers should be commonly installed as well as simply out of doors.
With potted readers, protection is greatly enhanced because the electronics are sealed in weather- and tamper-resistant epoxy potting for both indoor and outdoor operations, providing an IP67 rating, which assures the electronics are protected from water, steam, detergents, dust, sand, tools and other elements which could be used to impede data collection.
Scott Lindley, general manager, Farpointe Data, is a 25-year veteran of the contactless card access control industry. He can be contacted at [email protected]
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