Explosion protection thanks to intrinsically safe barriers

In hazardous areas, there are a range of protective measures to prevent the formation and ignition of an explosive atmosphere. The intrinsic safety type of protection plays an important role in process automation. Intrinsic safety requires us to consider the entire electrical circuit, which consists of a current/voltage source, consumers and cables. This means that in order to use intrinsically safe field devices such as sensors, transmitters or valves, intrinsically safe barriers are also always required. These barriers create a failsafe limit for the amount of energy within the electrical circuit so that no ignitable spark or thermal sources of ignition can be created. The intrinsic safety type of protection significantly simplifies the installation, handling and maintenance of field devices, as these activities can be performed during ongoing operation.

The following information will explain more about the functions, applications and advantages of isolators and safety barriers in hazardous areas.

ISOLATORS

The function of an isolator

In process technology-related systems, isolators – also known as isolated barriers – can be used to integrate field devices in automation systems. Point-to-point connections with conventional isolators are a proven and easy-to-use solution. These devices are based on the galvanic separation of intrinsically safe and non-intrinsically safe circuits. This ensures a high degree of safety as there is no conductive connection between the hazardous area and the "normal" world.

A good isolated barrier needs to be multi-talented. It has to provide reliable Ex i isolation, precisely transmit signals and accurately display error messages. They also need to be long-lasting and easy to install. They must therefore be suitable for a number of applications in hazardous areas. R. STAHL's ISpac isolator range is easy to use and boasts an impressive range of functions and a long service life. See for yourself!

Our products and their advantages

Only R. STAHL allows you to install all ISpac devices individually, in groups or in a pac-Carrier. Our comprehensive module range already covers a variety of applications and different uses, including functional safety (SIL). Evaluation according to SIL2 and SIL3 also encompasses devices with a trip amplifier function. With a combination of isolators, HART multiplexers and termination boards, HART signals are efficiently transmitted to asset management systems.

Isolators stand out thanks to their versatile application options and high compatibility with automation systems from well-known manufacturers. For transmitters, proximity sensors, indicator lamps or horns – we have the right solution for every application. Our range includes all signal types, from simple switching repeaters and supply units for HART transmitters to high-functional temperature transmitters with trip amplifier functions. The range of functions therefore covers the requirements of process technology systems and machine building applications.

The new modules are only 12.5 mm wide and offer the option for both 1- and 2-channel connections. This saves up to 30% more space, thereby maximising the available space inside the cabinet. They are particularly energy-efficient and suitable for use in a wide range of temperatures. Our isolators enable the safe operation of field devices across all sectors. They perform their tasks reliably even when directly surrounded by machines, on ships or in any high-vibration environment.  What's more, R. STAHL separating barriers can be used all over the world. The ISpac isolator system has been granted approval in accordance with IECEx, ATEX, FM, UL, EAC TR and a number of additional international standards.

Will everything work together? - Here, you can choose any compatible field devices from individual manufacturers or of specific types. Test whether your field devices are compatible with ISpac isolators or get an overview of the features and highlights of the ISpac isolator range:

SAFETY BARRIERS

The function of a safety barrier

Safety barriers, also known as Zener barriers, connect intrinsically safe circuits to non-intrinsically safe circuits such as Ex i field devices and control technology. A suitable barrier will always be found – an individual barrier or a combination of barriers – for standard signals such as 4 to 20 mA and for less common signals.

The barriers use a combination of Zener diodes, resistors and fuses to limit the electrical energy that enters the hazardous area. This means that there is no risk of ignition due to sparks or thermal effects. The cost-effective safety barriers protect the electrical circuits (cables and equipment) that are installed in hazardous areas. Unlike with isolators, however, this does not involve galvanic separation between the intrinsically safe and non-intrinsically safe circuit. A wide range of sensors is used for the automation of machines. In doing so, there are many things to consider. Every device requires the appropriate solution for Ex i protection. INTRINSPAK covers this spectrum with a range of more than 70 variants – with a footprint of just 12 mm.

As one of the pioneers in the safety barrier sector, R. STAHL places great importance on easy installation and maintenance. Installation is also incredibly simple. All you need to do is snap the barrier onto the DIN rail – this action also equalises the potential between the conductive parts. What's more, only one PA collective connection is required for each rail. An easily interchangeable back-up fuse protects the internal fuse and the barrier itself, thereby simplifying storage and maintenance. Details such as the combination of assembly and equipotential bonding connection or a uniform, exchangeable backup fuse make INTRINSPAK unique. See for yourself!

Our products and their advantages

Intrinsic safety with single or dual channel safety barriers. These safety barriers from R. STAHL enable you to operate HART transmitters, potential-free contacts, temperature sensors, solenoid valves, indicators and much more equipment in an intrinsically safe manner. What's more, R. STAHL safety barriers are approved for global use and are certified for UL, EAC, KGS, IECEx, ATEX and much more.

R. STAHL's 9004 series INTRINSPAK safety barriers are ideally suited to supplying field devices with intrinsically safe auxiliary power due to their electronic current limiting. Zener barriers are available for all application areas in automation technology and for all signal types, such as transmitters, control valves, solenoid valves, LED indicator lamps, vibration sensors and resistance temperature detectors.

Download our extensive product data sheet for all application areas. Or contact us directly. We are always happy to provide expert, professional advice from experienced specialists. We can also help you to choose from the range of suitable barriers or to assess simple electrical equipment.