IP67 I/O in Coal Production

In autumn 2006, the Shandong Electric Power Engineering and Consulting Institute (SDEPCI) began expanding the Yongchuan plant’s capacity with another two 135 MW units for processing lower quality coal. Extensive transport system run through the entire plant in order to transport the coal from its repository to the coal mills that precede the burning kilns. This is why the plant designers made great demands on the automation solutions being used. Ultimately, countless sensors and actuators spread all over the plant area have to be operated despite dust, dampness, vibrations, noise or electromagnetic interferences.

A conventional automation architecture would not have met these demands, which is why the plant designers chose a modern fieldbus system for the signal transmission between the PLC and sensors/actuators. The proper fieldbus system – featuring a modular design and IP67 protection – not only guarantees interference-free communication between all devices involved, but it also provides a high degree of data integrity, protection against vibration and extensive diagnostic functionality.

Defying dust and vibration

After analyzing fieldbus systems from different producers, the plant designers of Shandong LuNeng Engineering Co. Ltd. – entrusted with engineering and commissioning the new plant’s automation solutions – chose Turck’s BL67 series. In order to guarantee reliable operation in spite of dust and vibration, plant designers decided not to abandon IP67 protection – although each and every fieldbus station was to be installed in a control cabinet. Turck’s fieldbus system convinced the plant designers with another option: single I/O modules can be swapped in full operation. In this way, BL67 allows plant operators to replace broken I/O modules and avoid expensive downtime. Short-circuit protection and distinct diagnostic functionality that provide a quick status overview complete the system’s comprehensive safety equipment. Thanks to its modular design, the BL67 system can simply be expanded if necessary – whether digital, analog, temperature or other signals need to be integrated.

The modular I/O stations transfer all the analog and digital signals that reflect the transport system’s status – whether rate of feed, offset, distension, cracks or fill level data. The fieldbus stations are connected to the higher level PLC, Control Logix 5560 by Allen Bradley, via DeviceNet. After evaluating the obtained data, the PLC submits the plant’s status to the management information system (MIS). The plant designers implemented a total of two fieldbus networks – one covering 900 meters and the other covering 400 meters. Turck’s BL67 system absolutely convinced the planning engineer, Xiangyang Bai, ultimately ensuring future cooperations with Shandong LuNeng Engineering: “BL67 is a very good fieldbus solution that we are already planning to use in future projects,” says Bai.