But when the packaging company says Beckhoff is faster and cheaper, the bean counters eyes are going to glaze over. (more dollars per minute production)
"A PLC is a PLC right???" says the bean counter....
Yes, and downtime is downtime.
As others have said above, you could make good arguments for either AB or Beckhoff - but it takes more than a PLC to make widgets.
Have you factored in the cost of getting software and licenses for all the equivalent Beckhoff products? Are any of those software packages going to require updated PC's, newer versions of Windows, virtual machines, new technician laptops, etc? Have you factored in the time it will take to install, configure and test that software?
Have you factored in the cost of getting
everyone suitably trained and up to speed on a totally different, totally new platform? Not just the plant engineer, but everyone who ever looks at the stuff? Maintenance, night shift, projects team, etc?
Have you factored in the cost of obtaining, cataloging and storing all the spares required for another line of PLC's?
You buy a PLC once, so it's an upfront saving. But there are also a lot of upfront costs, and if you don't do it right, there are a lot of
ongoing costs that will wipe out your upfront penny-pinching in a heartbeat. How much does it cost to have the line down for even an extra hour because you couldn't find the laptop that has the Beckhoff software on it, or because you don't have that particular software package installed and licensed yet, or because the night shift guy didn't get trained yet and has to google how to get online with the PLC, or because that particular spare part is not in your stores, or is buried somewhere in a box in your storeman's office because nobody has given him a budget to buy more shelves to store all of this new hardware?
Even once you are all trained, until everyone has enough hands on experience to be as fast or faster than they are/were on the AB gear, every instance of downtime represents a net loss over AB, because it'll take you longer to diagnose the problem.
This is not to say "don't do it". Beckhoff is a valid choice, but if your bean counter's eyes are glazing over while their imaginary pile of beans gets bigger and bigger, you need to slap them across the face with a Beckhoff catalogue and make sure that they've factored all of the above into the bean pile. Do it PROPERLY, or don't do it at all.