There are times when you need only an intrinsic safety barrier or surge protection to get the job done. But what if you need more than just a component, something more customized, something like a complete system solution—including documentation and certification? Sure, you could always build your own and have it certified yourself. But it's time consuming, and the number of approval standards and certification bodies is enormous. You really need to be focusing on keeping your plant running.
The Internet of Things is an up-and-coming technology which is set to transform the way we live. Simply put, it allows machines to communicate directly with each other over the Internet. This connection between machines will lead to greater convenience and efficiency based on a more rapid exchange of information. Everyday examples might include a car telling a garage door when to open or close, a stove turning itself on to boil a pot of tea that will be ready for you when you come home from work, a timer setting thermostats, and your refrigerator letting you know when you’re running low on groceries.
Customized, certified solutions for hazardous locations
In Pepperl+Fuchs lingo, “SEC” stands for Solutions Engineering Center. Our newest SEC location is in Houston, Texas. Other SEC locations include one in Twinsburg, Ohio as well as international locations in England, Germany, Singapore, and Australia.
Purging a Class I/ Div. 2 HMI for Div. 1 applications is practicable
We get many questions about whether it is acceptable to put a Class I/ Div. 2 rated HMI into a purged enclosure for Class I/Div. 1 installation. It is certainly possible, but there are a few requirements.
Q. We have an industrial cabinet (1.2 m x 0.8 m x 2 m) that is segregated into two halves with a door on the front and back. We want to properly configure a Type X purge system for this enclosure. Air has the ability to freely flow between the two compartments. Our concern is related to this segregation/separation of the two compartments. We believe there might still be hazardous gas trapped inside after the purging process is complete.
We assign the term fieldbus junction box to an enclosure mounted in a remote location, near the process, containing some type of electronic distribution module for use in a digital ‘fieldbus’ application.
The module mounted within the enclosure typically provides short-circuit protection, current limitation, isolation, and other electronic monitoring to the connected field instruments/sensors and to the control system.
In a digital fieldbus network like PROFIBUS PA or FOUNDATION fieldbus, it is very important to provide protection against inadvertent shorts or other faults. FF and PA fieldbus networks share a single shield twisted pair for power and communication, so a fault of this type could potentially affect the entire network if the individual instruments are not isolated. This is the main reason it is NOT recommended to daisy chain PA and FF devices.
A Class I Div. 1 purge system is typically called a Type X purge. A Type X purge system is used to provide, control, and monitor instrument air or some other inert gas in an enclosure containing electronic equipment intended to be mounted within a Division 1 hazardous location.
...while located in the hazardous (explosive) atmosphere?
While maintenance/live-work on intrinsically safe field-wiring circuits is often confused with maintenance on intrinsically safe equipment, IEC/EN 60079-17 Electrical apparatus for explosive gas atmospheres – Part 17: Inspection and maintenance of electrical installations in hazardous areas (other than mines) provides some information on this topic that can be useful to the reader.