PLC Programming Software: The Pathetic Cash Grab

10 April, 2011 09:21PM · 3 minute read

One of the big parts of the automation industry that has always annoyed me is the seemingly pathetic cash grab for end-user and integrators money for PLC Programming software. Before we dive into that, a quick re-run of how the PC industry works.

The end-user/developer can buy a Mac or a PC for software development but if they want to develop for the Windows platform they also need to buy the Windows operating system (OSX comes with the Mac and is not licenced with keys etc like Windows but then, it only works on a Mac). That said, most PCs from major manufacturers (DELL, HP etc) come with Windows pre-installed and it’s part of the price of the PC hardware (effectively what Apple does). The hardware (the PC hardware itself) is useless without an operating system to tell it what to do. Hence both of these approaches makes sense: what’s the point of buying hardware that is useless without then buying additional software? If they tried it in the general consumer space the backlash would be immense. To the enthusiast though, building their own PC from parts and running Windows, the OS is an expense they understand they need to pay for separately. It also gives the enthusiast a choice - they could buy a version of Windows OS that would happily make any PC they assembled work just fine - the hardware wouldn’t matter.

In the PLC industry it’s more the equivalent of the PC hardware enthusiast market where PLCs don’t come in a made to order configuration but in pieces that must be put together: CPU, Power Supply, Digital I/O and Analogue I/O and Communications cards on rack(s). They also follow the Microsoft model selling the software needed to make it work separately¬†(programming software in this case).

The issue I have is this: PLC Hardware is proprietary such that the programming software used to program the PLCs is unique to that PLC (much the same way that OSX is locked to Apple hardware). In the case of OSX, this is fine since there is no additional licence for OSX. Yet for PLC programming software there is always an additional cost. In some cases upwards of $5,000 USD without which the PLC Hardware is useless.

The only reason that PLC hardware vendors get away with it is because the market is completely closed - they design and manufacture the PLC hardware, firmware and programming software. There is no open standard that allows one PLC Programming package to program them all. This lack of standardisation is fostering a lack of competition and a lack of innovation that has seen the PC industry take off into the distance while PLC/SCADA Automation technology is decades behind.

If the IEEE introduces a common PLC Programming interface standard (they’ve already been pushing open programming languages which is a good start) then some innovation might finally happen in this space. Until that time, prepared to be ripped off.