Linux OS in Industrial Use

[BobLfoot 301]

Imagine my astonishment the other night to learn that our six major Windows 2003 Servers for Data Collection and HMI tag serving are actually Virtual Machines running a Xeon Box booting linux. I've been hobby playing with linux at home for some time but was intrigued to see it in a Production Application. The last time I ran into it was on an oem's proprietary control scheme for a conveying system that was using PC controls and no PLCs at the time. I was just wondering whar others were seeing in terms of PC Operating Systems in the Industrial/Controls Field.

[gleblanc 1]

I'm actually surprised that we don't see Linux used a lot more. Not necessarily as the underlying layer on PLCs, as it's not very good at Real Time, but certainly on HMIs. The AB PanelView stuff uses windows, and crashes a lot more than I think is necessary. As for backend stuff, my wife's office runs VMware ESX (which is a custom Linux machine, + apps) on all the physical hardware, and then several other virtual machines under that. It's a lot cheaper than buying and maintaining multiple physical servers (think power consumption, redundancy, etc). It also allows much easier reconfiguration in terms of adding ram, disk, and processor resources. The last benefit is that boot times on a virtual machine are a small fraction of the boot times on a physical machine with many SCSI (err, SAS) devices. Polling real hardware takes real time, while polling virtual hardware is limited only by the speed of the processing and ram.

[Nathan 7]

Gleblanc - I agree with your points. Regarding VMWare ESX/ESXi, surprisingly, it isn't running on a custom Linux machine. The "console" is a virtual instance of a Linux build, which makes it feel like you're running Linux. Their "hypervisor" is actually their own creation. However, Xen and probably others run on top of a Linux "host" operating system. You can even run Hyper-V on Windows servers or other products on other platforms. Contrary to what some here might argue, they all can be configured to run solid. In every case, virtual machines are still constrained to the physical hardware that they run on, although there are efficiency benefits to be gained. I also found it surprising that quite a number of Inductive Automation (Ignition) users run Linux machines on the plant floor. I'm a bigger proponent of Linux in theory than practice, but it makes sense. I also like using Knoppix or Ubuntu disks to boot a (Windows) PC that's had problems - to recover files from, for example.

[RussB 22]

Maybe it would not surprize you to know that a lot of newer PLC/PAC processors are Linux based OS's. They are proprietary in most cases but that is how it is relatively easy to do web publishing and other hosting type of activities. Wind River does a fair amount of this development.

[DannyMan 0]

Yes, definitely a shame Linux isn't used in more industrial devices. The only industrial Linux devices I have been working with are the industrial grade wires and wireless routers, with DD-WRT firmware. Very good products.