Advantage of PLC
Despite the growth of alternative management solutions, the acceptance of the PLC endures. Mitsubishi Electric product manager Hugh Tasker provides 10 reasons you nonetheless have to have a PLC.
There seemed to be a period, not far back, when the PLC stood as the only practical choice for influence in manufacturing automation applications. Today engineers have much more choices in the form of manufacturing PCs, soft PLCs, and panel PCs which are the performance of the PLC/HMI combination. Engineers might, in case they felt so inclined, assemble their very own customized controller around a Raspberry Pi board.
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Despite the growth of these brand-new control options, you may still find many compelling reasons to use a PLC. Here are only 10 of them.
1. Peace of mind
Both PCs and PLCs came quite a distance since their humble beginnings of theirs but there’s a huge difference in the way these unique control alternatives continue to develop and this has ramifications that are significant for extended support. The managed evolution of the PLC suggests that vendors can easily and do support their products over extended periods, both regarding software programs and hardware. This implies, with Mitsubishi Electric for instance, we might use the application plan for instance, from a twenty-year-old FX PLC and import it directly into a new FX5U. A person can set up the very latest controller and also have the application back all set up very quickly. Would you contemplate doing the same with a desktop-based solution?
There are lots of industries where that degree of assistance isn’t just desirable but a baseline requirement. There’s a conversation in the water business, for instance, of framework suppliers being forced to have the ability to guarantee support of control devices for as many as twenty years. The control hardware is going to change over that time but PLC computer users hold the reassurance of realizing that the application will port to the most recent controller.
2. Reliable and robust Inherently
The modern industrial PC offers a healthy computing platform it will be unfair to claim it locked up and crashed with the unerring regularity of a desktop PC. Nevertheless, it’s not on equal terms with a PLC.
The actual time operating system which runs alongside Windows on an ordinary industrial PC is created to attempt to offer a similar degree of robustness that you receive from a PLC CPU.
If a desktop operated in total isolation, perhaps that could be the conclusion of the dependability debate. However no controller does; there are peripherals to connect, I/O to other elements, and a network to speak to, each one needs its very own drivers being packed into the PC. Will the drivers for every one of these items be evaluated together and completely proven? It appears to be unlikely. Clashes will and do occur and difficulties may be exacerbated every time those owners are updated.
It’s just about unavoidable, then, that an industrial PC will crash and also what might that mean for the management process? By comparison, when did you last pick up of anyone having to reboot a PLC after a program crash – probably never…
3. Scalability
The largest selling PLCs by volume covering the biggest spread of uses are those offering forty I/O or perhaps less. In such programs, the PLC represents a very inexpensive solution, more so than an equivalent PC-based system. Nevertheless, the same important platform is scalable to tens of thousands of I/O, with owners ready to port management plans to bigger PLCs, benefit from a similar programming atmosphere, and also get the advantage of completely modular hardware.
The customization potential of the PLC is huge, with several ways to grow the performance but all without having to leave a typical platform.
4. Programming
To this day, for every engineer coming from faculty who’s fluent in set-up text programming plus for each more comfortable engineer, you’re in C++ or C, you will find likely 10 much more who just need to make use of ladder logic, especially at the low I/O conclusion of the application spectrum.
In between, you will find all those apps which could begin small, possibly authored in the ladder but next develop as the software evolves – benefiting from the scalability of the PLC platform – benefiting from the capability to create the management software in the text that is set up also to drag and drop software function blocks which will take away most of the setup effort.
At Mitsubishi Electric we provide a C++ programming alternative for our PLCs, therefore we marry a flexible hardware platform to higher-level language programming capability Of course these identical programming choices are readily available for a PC platform, though the amounts of modularity and also scalability that PLC software tools offer – in very much the same fashion like the hardware – just are not there.
5. Integration of some other automation equipment
For a lot of automation engineers, there’s no need to go outside of the product portfolio of one merchant, with vendors like Mitsubishi Electric in a position to deal with each requirement from HMIs, drives, servos, motion control, robotics, and brilliance to very low voltage power distribution solutions, energy management meters and also CNC systems. Because every one of these parts is created to work in concert, engineers benefit from’ plug and work’ integration.
Several automation vendors will provide industrial PCs who could state they give a broadly similar product portfolio but surely very few. Nevertheless, the true problem comes when engineers have to look outside of one manufacturer and incorporate third-party components.
With the modern-day PLC, integration of 3rd party hardware is a breeze; could precisely the same be said for integration holding a computer platform? Will be the drivers for all those third-party modules guaranteed to the office? Just how much configuration effort will be needed? Maybe much more notably, will there be the same assurance of ongoing compatibility via the operational lifetime of the management platform?
6. Performance
With regards to effectiveness as well as power, Moore’s law of computational ability is equally as relevant to PLCs as it’s to PCs – a lot of people fail to remember that the modern-day PLC is a great pc in its own right. The newest incarnation of the Mitsubishi Electric FX PLC, for instance, is 150 times faster than the initial.
Just how effective the modern PLC is just actually becoming obvious whenever you glance at the pace of execution of directions, with the newest designs offering sub-nanosecond performance. You may be ready to pimp’ a computer to give functionality that is similar but the PLC provides you with that straight from the package. After that there’s the enhanced capability and bus speed to synchronize many I/O in a highspeed system, giving you a more responsive management system. Once again, this’s a lot more difficult to obtain outside the PLC environment.
7. Security
The appearance of high-profile viruses including Stuxnet has created people to realize that automation devices are becoming targets, as malicious hackers look to damage the operations of crucial utilities or maybe great businesses. With their usual operating system and inherent network vulnerabilities, the PC can stand for the soft underbelly of the management system for anybody attempting to get broken in. The OSs of PLCs, by contrast, are less noticeable to the external world which has usually sold a level of insulation against malicious intent. This doesn’t mean, nonetheless, that PLC manufacturers take protection as a given. Mitsubishi Electric, for instance, allows applications to be password protected, with various levels of access granted to various levels of consumers.
Further remote access preferences might be established including entry just being given to particular IP addresses, protecting the PLC software program plus the broader automation system while in heavily networked applications.
8. Intellectual property
Extending the security argument, an issue for businesses with worldwide development teams or even where the conclusion product can be fitted overseas would be that the management program is copied by unscrupulous third parties and very quickly produced as a competitive, less expensive item.
Exactly where this’s a legitimate concern across all control platform choices, the PLC producers have taken considerable steps to handle the issue. With Mitsubishi Electric products, encrypted code embedded in CDs and hardware could be placed to perform at a certain period. That may suggest the method is ready to accept installers and developers through to the conclusion of commissioning of the application program, however, switches on to defend the device from further interaction.
9. Maintenance
Every automation process, regardless of platform, requires regular maintenance; probably to handle hardware or maybe software upgrades, as part of scaling up the device because the software evolves, or maybe, to swap out faulty components. The simplicity with which this could be achieved is the main appeal of the PLC. Programs and also configuration settings for almost some connected portions could be saved to an SD card via a slot within the PLC CPU, simplifying any maintenance requirements.
Certainly, even if the PLC CPU itself were failing, a brand new device might be snapped onto the backplane and also the first system loaded directly from the bootable backup on the SD card, getting the device back all set up straight out.
At the same time, there is not one of the demands for ongoing firmware updates that will plague PC-based methods, with the regular worry that any one of those will conflict with another and bring the device to its knees. The very fact that the PC is a multi-purpose program is among the most notable weaknesses of its automation environment.
10. Reduced IT requirements
Among the questions in virtually any automation process, much more so as integration between the plant floor and greater level techniques is into the situation, will be the allocation of duty between the automation engineering group and also the IT staff. This may be a supply of friction but maybe more importantly there’s the nearly inevitable lack of knowledge from each about the demands of the different.
With PLC-based automation, the demarcation between engineering and It’s apparent, with very little or maybe no demand for the IT staff to need to engage on the plant floor. Additionally, with items like Mitsubishi’s Electric’s MES module – which plugs into the PLC backplane and also has an immediate link with level higher databases – whole tiers of PC solutions could be removed from the automation process altogether, making the demarcation between automation which more clear.
We can see, then, which you can get a lot of great reasons the PLC continues as the mainstay of automation process management and that is before we have also considered problems for example redundancy, brilliance, and much more, and also the ability of the modern-day PLC to do a lot of the intricate maths capabilities that may when have just been done in a PC based system.
Of course, the demands of every automation system must result in the number of the appropriate command solution on merit although PLC provides factors that many to become the platform of preference.
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