The September technology evening was held at Umhambi lodge where Beckhoff managing director, Kenneth McPherson, gave a presentation titled ‘EtherCAT, the Ethernet Fieldbus’. Kenneth kicked off with the principle of operation of the EtherCAT technology and then touched on performance, topology, benefits, diagnostics, interfaces and openness.
A comparison with other Ethernet based fieldbuses like Profinet and Modbus TCP and Ethernet/IP was also given. Kenneth explained that in conventional Ethernet, a complete Ethernet frame has to be sent even for small data quantities creating a common Ethernet problem of bandwidth. He explained that with EtherCAT, each EtherCAT slave controller reads the data relevant for the device while the data frame passes through it. Kenneth used the analogy of a bus slowing down for slave devices to load and offload packets located on specific seats without actually stopping the bus; he called it Ethernet on the fly.
With EtherCAT, the Ethernet remains intact down to the individual I/O which means there is no additional sub-Bus required. Because of the EtherCAT technology, update times of less than 30 μs for data from a 1000 distributed I/O could be achieved. The evening was well received by the members and guests that attended.
Additional technology evening
The technology evening originally scheduled for 8 August had to be moved to September due to a public holiday that fell in the same week. Evan Dent, strategic business manager Endress+Hauser South Africa, gave a presentation on the 12 September at the usual venue.
The issue of energy management is always taken for granted because people do not understand what is involved. Evan introduced the five utilities common in any plant and he called them WAGES – water, air, gas, electricity and steam.
The most important thing Evan stressed was to install the right equipment to measure what each section of the plant is consuming. It would then be easy to monitor any trends in consumption and also to determine the biggest consumers or users. Evan gave an example of how much energy is lost by a small air leak running throughout the day, if the leak continues for a week, a month or a year the loss can easily run into hundreds of thousands of rands.
Evan then introduced what he called the three key elements in an automated monitoring and targeting system. The three element system consists of the utility metering (which he again stressed as the most important element), the data collection and the analysis. Nowadays, a number of software applications are available for data collection including scada systems and data loggers. The presentation was followed by an open discussion over snacks and drinks.
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