Wireless in the Ex Environment A Safe Way of Wireless Process Automation via the GSM Network

Editor: Dr. Jörg Kempf

Seamless documentation of all process values is required in order to further optimize processes and systems. Previously, far-away systems such as tank farms and pump stations could only be incorporated into the process automation with a large investment or not at all. The GSM network offers a simple solution to this problem if the safety criteria for areas subject to explosion are taken into account.

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The Ex-box is certified according to Atex and IEC-Ex and can thus be used worldwide in Ex zone 1. (Pictures: Wago Kontakttechnik)
The Ex-box is certified according to Atex and IEC-Ex and can thus be used worldwide in Ex zone 1. (Pictures: Wago Kontakttechnik)

Wireless technologies are a wide- spread transmission medium in the process industry. WirelessHart, radio, Bluetooth, and GPRS are used for data transmission. Since in the meantime GSM/GPRS cellular telephone networks are available in more than 200 countries, they make it possible to transmit data worldwide. Country-spanning communication is significant precisely in the process industry with production locations around the world, but also anywhere where long distances must be bridged. Wireless technologies are a very economical and safe alternative to wired transmission. On the one hand, no cables have to be laid, which saves time and money. On the other hand, wireless technologies offer the advantage that they are largely independent of the explosion protection type of the sensor in question. Thus it is possible to construct intrinsically-safe systems and systems with increased safety without wires without having to use additional cost-intensive Ex barriers.

Certified complete system

Wago’s To-Pass product line uses the GSM network for communication and incorporates field-side signals via wires or Bluetooth. To-Pass modular is an especially scalable toolbox for remote applications. From this, Wago has developed a complete solution for the Ex area together with Ori Abwassertechnik. Ori is not just a specialist in battery-supplied Bluetooth sensors, it has also gained extensive experience in explosion protection. Together, the companies decided on a solution in an encapsulated, pressure-proof housing, the so-called Ex-box. It is certified according to Atex and IEC-Ex, which means that it can be used worldwide in Ex zone 1. The box is already completely equipped and includes a 24 V power supply, a 2-port Ethernet controller, a 2-channel relay output module (for switching warning lights), a 4-channel analog input module (4-20 mA), two serial interface cards, and the Ori EMBT 2.2 Bluetooth module.