Ethernet products improve industrial safety
28 August 2008
Ethernet products are increasing in popularity, especially where their use can improve process safety They are finding particular applications in areas where conventional methods may not work. Mining is an industry where special controllers are needed to be both safe and rugged.
Ethernet products improve safety
Coal is a valuable resource and is used as a low cost, quality fuel for many power plants. Mining operations are being equipped with sophisticated industrial controls and sensors for safety and operations efficiency. In many mining applications, live video data is joining with information from sensors and industrial controls, pushing the bandwidth requirements up and causing serial technology to be upgraded to Ethernet over fibre media. Ethernet is preferred for its interoperability, flexibility, and cost effectiveness.
PacifiCorp operates the Deer Creek Mine, an underground coal mine located in the Wasatch Plateau in Utah. The mine extends for about 18 miles and has used serial technology for information. In designing a systems upgrade, PacifiCorp ran into limitations in both distance into the mine and the total number of serial end-devices that could be supported.
The environmental controls system is a seven-days round-the-clock operation that is critical to keep the mines safe and also for management of the control systems. Using the system, PacifiCorp evaluates underground air quality and whether it is safe for workers to enter the mine. Carbon Monoxide (CO) sensors and Methane sensors are used underground to monitor the air quality. PacifiCorp also needed live video data to monitor the equipment in the mine, instead of sending manned vehicles to the equipment location to get operations status data. All of the mine equipment and environmental information needed to be available without interruption in order to support operating decisions and to avoid compromising safety.
Ethernet technology opens up the ability to have an industry-standard common network for all of the real time information that is crucial for safe operation of a mine. Shared Ethernet media readily handles bandwidth and a number of end-devices limits, which had been considerations for serial lines. Fibre media is future-proof for speed, and single-mode fibre easily handles the huge distances. For high availability, PacifiCorp implemented a single-mode fibre loop in the mineshaft to establish a ring structure that can provide self-healing fault recovery.
PacifiCorp chose GarrettCom’s Magnum switches and the Magnum S-ring Redundancy Management Software to meet their application requirements. They chose GarrettCom because of its cost-effective range of managed Ethernet products, fibre port configurability, industrial rating, AC and DC power options, and proven track record in industrial networks. PacifiCorp has different network Scada systems and VLANs to keep track of PLCs, environmental conditions, Longwall mining machines, Beltline conveyors, and pump stations. In addition, they are in the process of adding many IP phones and video cameras. All these networks are connected via the Magnum switches. Magnum 6K25 Managed Fibre Switches are used in the main office to interconnect with other switch brands. Magnum 6K16V switches are used in the underground control stations and are attached to end devices. Magnum mP62s and HMI units in NEMA enclosures are in the mining area.
The use of Ethernet products in the Deer Creek coalmine has provided PacifiCorp with safe mining operations. The S-Ring Redundancy Manager Software with Magnum Switches allows PacifiCorp to eliminate network downtime inside of the mine, keeping information flowing at all times and informing them when the mine conditions are safe for workers to enter the mine. The sealed case of the Magnum mP62 Switches is ideal for the mining environment, providing protection for the switch’s internal electronics from dust and dirt. The per-port configurability of the Magnum 6K product line provides PacifiCorp with flexibility and cost-effectiveness should future expansion be required.
Ethernet products are also being used to improve safety in tunnels across Europe. Fires can be lethal in road tunnels, where heat can build up extremely quickly. Across Europe, tunnel fires have killed over 90 people in the last ten years. This was one of the driving factors in the set-up by the European Commission of EuroTAP – the European Tunnels Assessment Programme. EuroTAP was established to test tunnels across Europe, and to make recommendations for safety systems and procedures.
Among the many measures identified by EuroTAP was the need for an effective network of emergency telephones throughout a tunnel – not only to provide fast warnings to emergency services in the event of a fire, but also to provide reliable communications points for the public in the case of accidents or breakdown. The integrity of this SOS telephone system is paramount, since mobile telephones are unlikely to work deep in the heart of a tunnel. Yet the failings of conventional technologies were visibly demonstrated to the world in May this year when, in a 22-car pile-up in the Harvey Tunnel in New Orleans that saw 24 people injured, none of the emergency telephones were found to be working.
In Italy, the Mont Blanc incident provided the stimulus for a series of research and development projects aimed at optimising safety conditions in tunnels. Recent years have seen a host of Italian companies and universities active in ITS research and development projects associated with tunnel safety, focusing on innovative components and integrated systems.
Much of this work is already coming to fruition in both new tunnel projects and in reconstruction projects on existing tunnels. One example is the installation of a new VoIP (voice over internet protocol) emergency telephone network, installed by Italian system integrator Fort Fibre Ottiche, using VoIP phones from Teleindustria in conjunction with hardened Ethernet switches from GarrettCom Europe.
The ES42H is an industrially hardened version of the standard ES42 Ethernet switch, using high-grade components and constructed using a ruggedised metal case to deliver absolute reliability in the most demanding environments. A key feature is the use of patented thermal techniques which mean that no airflow is required for cooling, allowing the switches to be constructed impervious to dust, dirt, moisture, smoke and insects. These features make the ES42H an ideal choice for use in tunnels, and were a key factor in their selection for this application.
The compact design provides six Ethernet ports including up to two 100Mb fibre ports. The fibre port choices cover all multi-mode and single-mode fibre connector types. For use in the tunnel, ES42H models were selected suitable for operating directly off the mains power supply, and offering the highest speed and bandwidth over single-mode network.
The switches are linked over fibre on twin ring networks – with the VoIP phones divided evenly over the two rings. Both rings connect ultimately to a GarrettCom 6K8 managed Ethernet switch which connects the VoIP phone network to an IP-PBX (internet protocol private branch exchange), and from there through a gateway to the normal public switched telephone network (PSTN).
The hardened switches ensure the highest degree of operational reliability, but the ruggedness of the network itself is further enhanced through the use of GarrettCom’s S-Ring technology, delivering high speed fault detection and correction. The S-Ring software runs on the 6K8 switch and monitors the ES42H switches on the two VoIP telephone rings, offering fast recovery in the event of a network break. Should the ring be interrupted, S-Ring acts immediately to change the ring into two topological strings, ensuring that there is a path through the two strings for all normal data traffic. Where the commonly used network recovery technologies offer recovery in around 3 seconds, S-Ring ensures network recovery in just 250msec.
Following numerous accidents due to poor safety standards GarrettCom has highlighted that Ethernet products are necessary to raise levels of safety, particularly in areas such as mines and tunnels where mobile phones are unlikely to work.
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