FBCon distributors enhance seamless communications

In a number of industries including food processing, primary industry and chemicals, field devices capture a variety of process data and send the information over Profibus PA to a controller or control system. The FBCon fieldbus connectivity system helps minimize the amount of time and material that is needed for installation, and it supports connection and monitoring of multiple instruments or sensors on Profibus PA via a fieldbus distributor. Two current examples are the new sugar factory located near Cumra (Turkey) and the adjacent bioethanol plant.

Konya Seker is Turkey’s largest private sugar producer. The company has invested heavily in state-of-the-art production facilities in recent years, and it is currently carrying out the largest investment project in the European sugar industry. The new sugar plant went into operation at the end of 2004.

Bioethanol plant

Every day, the facility processes 14,000 tons of sugar beets to produce about 1,800 tons of sugar. It is located near Cumra, a small city with a population of 40,000. At the end of 2007, an integrated bioethanol production facility was erected at the complex (Fig. 1) to make animal feed and bioethanol from the waste products that accumulate during sugar production. The facility currently has an annual capacity of 84 million litres.

During construction of the new facility and especially during design of the automation systems, the development team concentrated on achieving two goals that for a long time were considered to be mutually exclusive. They wanted to deploy cutting-edge technology which sets new standards in the sugar industry, but they also wanted to establish new business performance benchmarks and achieve a level of production efficiency which surpasses existing plants by a wide margin.

The decision to use Profibus for plant-wide automation was an important step in the right direction. Profibus provides seamless integration between the control system level and about 600 field devices, about half of which are PA devices. The bus carries process data traffic as well as all of the calibration information. This solution significantly reduces the engineering workload. The systems and control stations are connected to an internal Industrial Ethernet network. The plant has an Internet link to the main facility in Konya which is 30 km away.

The Profibus PA variant (PA = process automation) is designed specifically to meet the needs of process engineering, including power distribution on the bus and intrinsic safety. Profibus PA supports connection of multiple sensors and actuators to a single bus line. Power is distributed to the devices over a 2-wire cable, which minimizes installation effort.

All of the fieldbus devices in the sugar plant and the bioethanol facility are connected to the Profibus via Weidmüller FBCon fieldbus distributors.

The distributors are part of a complete Profibus DP and Profibus PA connectivity system which includes a large range of accessories. FBCon fieldbus distributors support various process automation bus topologies such as line, tree and star. Trunk lines branch off into multiple spur lines. Field devices which have the appropriate port (Profibus DP or Profibus PA) are attached directly to the spur lines. A terminator is installed at the end of each segment.

The fieldbus distributors have a trunk input and a trunk output for looping through on the trunk line. A selection of cable glands and connectors (M12) is available for the branch lines.

The distributor is connected to the higher-level Profibus DP network via a segment connector. In explosion hazardous areas, segments can be up to 1000 meters long, and maximum spur line length is 30 meters. The bus can be wired in a line, tree or star configuration. Up to 10 Profibus PA devices can be attached to one segment.

The fieldbus distributors are supplied in a rugged aluminum or stainless steel case, and they have connectors for 1-2-4-8 field devices. A limiter on each spur line automatically shuts down the line if the current exceeds a predetermined level (can be set to 20, 40, 60 mA) or a short circuit is detected. This prevents a total communications blackout on the segment if a fault occurs, and the system can continue to run.

Being equipped in his way, FBCon distributors enhance seamless communications in the sugar factory as well as in the adjacent bioethanol plant.