PLCs – Mitsubishi’s new Generation X
November 30th 2005 Mitsubishi launched its next generation compact PLC in October, billing it as the culmination of quarter of a century’s R&D efforts.
Faster, more powerful and with increased functionality, flexibility and connectivity, the FX3U is the result of customer feedback, according to business development manager Hugh Tasker. “We like to think that we lead the market, which means we must listen to our customers – and also other manufacturers’ customers. So what do customers want? Peace of mind – a reliable product that is flexible and easy to use for a variety of applications,” says Tasker. “They also want profitability, therefore it has to be quick, easy to learn, high specification but low cost – so we have to continually up the spec of the product or the same price.” Tasker claims it is hard to make the PLC any more reliable: “The level of failure is so low that it’s extremely difficult to measure. But we can make them more profitable.” According to Mitsubishi, the FX3U’s performance benefits enable this.
Specifications
FX3U’s specifications have been improved from between four to eight times. For example, the processor, at 65nS, is four times faster than its predecessor (“faster than most larger PLCs – including our own,” according to Tasker) while memory has been increased to a whopping 64k. “In PLC terms that’s huge,” says Tasker. “Effectively it means customers will never have to worry about memory again.” Along with 75 new instructions, I/O increased to 384, an easier to use analogue I/O and new Ethernet plus Profibus modules, Mitsubishi hopes not only to serve existing customers, but take market share from other manufacturers simultaneously: “We’d be pretty disappointed if this only attracted existing customers,” says Tasker.
However, that’s not to say the company doesn’t value its current customer-base. With over 6,000,000 PLCs sold globally to date, there is a huge replacement market for the FX3U – hence the system’s high backwards capability. “We don’t want to ignore existing customers which is why there is such a degree of backwards capability,” says Tasker. “For example, it takes only six clicks to upgrade from gen 2 to gen 3 and customers will also be familiar with some of the hardware and software.”
Mitsubishi is also keen to promote the system’s programming simplicity, and says its PLCs are used by colleges and training centres because of their ease of use. Developer software with 1000 steps is provided free of charge, as is a virtual PLC training module.
Because of the increased memory, structured modular software can now be made, so software becomes reusable: “Customers can develop building blocks to be used for unlimited applications – write once use infinitely with no more memory concerns,” says Tasker. “Also structured test means Ladder no longer has to be used which appeals to the next generation of engineers – which are our future customers. And it also allows more sophisticated applications.”
Along with reduced scan times (meaning this is no longer an issue in complex processes), system design time is on average 18% lower than with the FX2U. Mitsubishi says this is down to the 75 new instructions which allow the user to manipulate data much faster while direct addressing of analogue modules mean analogue control code is reduced 50%.
Combined with increased connectivity options (it now supports Profibus, DeviceNet, CCLink, ASI, CANopen and Ethernet – plus an optional USB interface) Mitsubishi believes the FX3U will appeal to a broader spectrum of users than the previous model. “Especially with the addition of Ethernet,” says Tasker. “To a man our customers asked for it. Because people feel very comfortable with Ethernet, they understand it – which opens up your plant to so many more users because they are not afraid of it. So you can extract the data that has always been there but until now, has not been used.”
Mitsubishi claims it is the only compact PLC with a Profibus master – which enables it to link with other systems. “In all,” says Tasker, “the FXU3 gives unrivalled flexibility for designers and process engineers. “It is a platform that encompasses a vast range of applications, both OEM and end user, for automation positioning, process control and networking. With such speed, memory and standard features, users are only limited by their imaginations.”
The company also announced that all its PLC products will be RoHS compliant by the year end. More articles from Mitsubishi Electric Europe: | 
