Background
Based in Keelung, Taiwan, original equipment manufacturer Afatek Industrial Consultants, Inc. is helping port material handling operators get cargo off ships faster and more safely.

Taiwan's harbors are very busy. More than 740 million 20 foot containers moved through Kaohsiung harbor in 2000, making it the fourth most productive container harbor in the world at that time. And Keelung Harbor is the second most active and productive harbor in Taiwan. Afatek has been a key contributor to the success; the company worked closely with its customers (for example the Keelung Harbor Bureau, Taichung Harbor Bureau and OOCL), to ensure that the cranes in use run as efficiently and safely as possible.

Maintaining that high level of activity requires precision and dependability. "For crane operations, safety and reliability are keys," said D.C. Wu, engineering manager for Afatek. "Consider the movements in unloading a ship. The crane's boom, moving up and down, is across the ship. The hoist operation is just above the trailer and the trolley operation is actually carrying the operator." With each article being moved from the container being very heavy, financially disastrous and potentially fatal repercussions accompany any significant error. That's why Afatek relies on Rockwell Automation PLCs, drives, motors and other automation components to maximize speed, yield and safety.

Challenge
Unloading with uninterrupted operation is the best way for Afatek's customers to get the highest return on their investment in cranes and the systems that control them. Consequently, maintenance is critical. Downtime for the cranes averaged 25 hours per month. Afatek sought to reduce that downtime. Plus, increasing the number of "moves" a crane can make each hour results in increased productivity. With the right control system in place, speed can be increased without neglecting safety.

As a result of advances in shipbuilding technology, the ships that Afatek's customers unload carry more cargo and have increased in both width and height. Consequently, the cranes need a higher gantry and longer boom than before. When Afatek assessed the task of refurbishing and increasing the size of the cranes, they realized that even though the upgrade would require replacing virtually everything (including the wiring), the first thing they needed was a flexible, reliable, easy-to-obtain PLC with easy-to-learn programming software.

The 17 cranes that they service incorporate products from a variety of suppliers, including Siemens and GE. As a result, the system that provides enterprise control, monitors the throughput and system status, as well as the machine diagnostics, needs to be able to communicate seamlessly with the heterogeneous mix of devices.

Also, incorporating new controllers into the system would make post sale support and training necessary.

Solution
Afatek chose the Allen-Bradley PLC-5 to serve as a major component in the control system. With mean time between failure averages o more than 300,000 hours, the PLC-5 is incredibly reliable, which helps Afatek's customers meet their goal of uninterrupted operation.

According to Mr. Wu, "The PLC in the system is mainly for safety interlocking, which is so important to crane operation due to life and property associated. Monitoring and controlling the DC drives for each motion are also incorporated in to the PLC functions."

As part of the solution, Afatek chose to use RSLogix5 and Rockwell Software's 6200, the most powerful, friendly programming software running under DOS and MS Windows. In addition to communication with the PLC, the software's broad networking capability enables it to interface with non Allen-Bradley components in the system.

Rockwell Automation Taiwan's Global Manufacturing Solutions group provided training, technical support and parts exchange and remanufacturing services. Because Allen-Bradley's PLCs are so popular, they are readily available. Also, being very modular PLCs can be swapped into place and easily programmed to provide the control.

Results
Fast delivery and strong post sale support have helped Afatek to refurbish their customer's cranes rapidly. And, so far, no failure has been reported on account of Rockwell Automation equipment. The bigger cranes have more capacity as a result of their size and the speed of their operation has increased from 25 moves/hour to 30 moves/hour.

Perhaps the most significant result is dramatically reduced downtime. Downtime averages 10 hours/month now, compared with 25 hours/month with the old control system. Technical support, when needed, is provided quickly, maximizing productivity.

Finally, the "transparent" new system has been very easy for operators to use. With a minimal amount of training, Afatek's customers have increased productivity, reduced downtime and maintained the highest level of safety possible.