11 August 2008
The key components of the new platform are the processor modules for the four different control disciplines. The control and communication tasks are shared by one PLC central processor and up to three other CPU modules. These modules exchange data cyclically via a new high-speed backplane bus, accessing a common memory with a capacity of 14,000 words. The bus communication is synchronised with the data processing clock rate of the processors, with a cycle period of 0.88 milliseconds. The iQ platform includes an interface module for the high-speed Gigabit Ethernet network CC-Link IE (Control and Communication Link Industrial Ethernet). Photo—The iQ controller combines four platforms in one. Starting at the left, next to the red power supply, is the high speed sequencer, or PLC; next the motion controller, CNC, and robot controller.STEP-BY-STEP OPTIMISATIONFor backwards compatibility, the new backplanes are equipped with two buses: the new high-speed bus and the same system bus used in the existing MELSEC System Q platform. This backplane bus enables the flexible expansion of the iQ platform with expansion and special function modules. Nearly a hundred different I/O, special function and networking modules are currently available. The existing standard, PC and process CPU modules—for example for redundant controller architectures and high-level language programming—also use this communication channel and are thus compatible with the new system, protecting existing investments in the Mitsubishi modular controller technology. The controller is programmed with a completely overhauled IEC 61131-3 GX Developer 2 software package, which is used for all Mitsubishi Electric’s compact and modular controllers. Mitsubishi says it has added many new functions and diagnostics and simulation tools make programming fast and efficient and to support smooth communication between the four different controller systems. THE UNIFICATION CONCEPTMitsubishi development engineers went through much ‘trial and error’ before the reality of the iQ Platform emerged. Control Engineering Europe recreates the development process through a discussion that was held by all the leaders in the process—and it involves a lot of passion and battles waged between ‘competing’ engineering camps.As is usually the case in automation products today, it was the customers who drove the development. Hikaru Kaneko, Chief of NC System Division, said a customer told him three years ago, ‘Instead of just NC, couldn’t one controller handle the sequencer, motion, and robot too? Wouldn’t Mitsubishi have what it takes to do that?’ That request, he says, was the starting point. ‘We initially did this only with NC, but they (the customer) said no, they’re expecting more from Mitsubishi Electric as a whole.’But there were the familiar engineering ‘cultural’ barriers. Kumio Saito, the leader of the project, said, ‘Each of us approached products differently and had different functions in mind. I guess we were coming from different cultures. At meetings, even if I spoke up, thinking I was right, everyone listening would each interpret what I said differently. So, we first started with understanding each other’s products.’‘And it didn’t make sense to keep talking forever about what we ‘will do’ and ‘will not do,’ so we set aside whether it was actually possible, and decided to look into the specifications of what we would want to make,’ said Hideaki Morita, who oversees the entire engineering sector of the Factory Automation system business.‘We forced the sharpest engineers from each department to come together, and concentrated on that for about a month,’ he said. ‘But they surprised us. The engineers involved were having a great time, their eyes sparkling while they said ‘let’s make a high-speed bus,’ or ‘an ASIC like this would be cool.’ That shocked us into realising something. We’ve actually never given them a place to discuss their dreams like this. Engineers actually enjoy getting together and talking about their dreams. That’s the starting point. Somewhere in that process, our cultural differences gradually melted away. OTHER ARTICLES ONLINE Control Engineering Europe presents an informal discussion of Mitsubishi’s development engineers as they talk about the iQ platform. To go to the discussion CLICK HERE For readers who want more specialised in-depth information about the iQ Platform from an engineer’s perspective, CE-E has put together this section that describes the positioning of the iQ Platform, its technical overview, and the specifications and characteristics of the compatible products. To go to the technical article CLICK HERE
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