PLC life span
PLC life span
(OP)
In number of years, what is the average life span of a common PLC? In other words, how long will they work before they need to be replaced?
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RE: PLC life span
The problem comes when in 9 years something blows and then you have troubles finding the particular replacement card.
If you have really benign conditions room temp, no inductive loads, clean power, short connections, low cycle times, and clean environment then a PLC could last for 20 years.
RE: PLC life span
Generally, something in the system gets upgraded and the PLC requires updating before its reached the end of its life (hardware wise), which very well could be 20 years or more.
RE: PLC life span
I would say: Plan to change the whole thing every tenth year. That will keep your systems serviceable and also user friendly. And try to stick to one set of hardware during that period. It makes everything much easier.
Gunnar Englund
www.gke.org
RE: PLC life span
I know that this particular machine is STILL in production today. Just remember to keep a DOS capable (not psuedo DOS like XP) laptop around so you can run the application software. Oh, and get ready for the lightning quick file transfers at 4800 baud. (And we thought dial-up was slow!)
There is some proof for the 20+ year pudding.
Hope this helps,
Scott
In a hundred years, it isn't going to matter anyway.
RE: PLC life span
We are not adding additional IOs to it. We can still get IO modules that work with it (the new ones are backwards compatible), just not necessarily the original models (but then, the old model is probably not so good anymore).
I guess we are hoping it will go another 12 years ... so the life span is about 20 - 25 years?
RE: PLC life span
Unfortunately for those users, I killed off those brain cells long ago... I usually just recommend they bite the bullet and upgrade for performance issues anyway.
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: PLC life span
I have the same situation when it comes to old analogue control systems. I am the only survivor from the seventies that still is mobile enough to actually help people with these dinosaurs (like Modulpac, Transidyn, Combiflex and so on). It gives me a lot of interesting travel to all five continents. But on the whole, I think that it would have been a lot more cost effective to replace them with modern ones.
Gunnar Englund
www.gke.org
RE: PLC life span
LOL.
RE: PLC life span
Gunnar Englund
www.gke.org
RE: PLC life span
RE: PLC life span
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I don't suffer from insanity. I enjoy it...
RE: PLC life span
And it will only cost you $49.99 with a 10 year service contract.
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: PLC life span
I have five A-B PLC-2 racks installed circa 1985, and think we've had one legit hardware failure (a bad input module) maybe a year or so after installation. Just remember to change out the memory backup batteries on a reasonable schedule.
It may be that the overall limiting factor is how long it takes for the electrolytic capacitors to start drying out, and failing.
RE: PLC life span
I/O is usually the hardware that dies,,,, I'm trying to think if I ever ran into a CPU failing without having had major damage as the cause!
The problem is kinda like backing-up your hard drive; when it crashes you find out how good your backups were. Sure, it's possibly cheaper to replace a PLC than keep repairing it after some point, but if your prog and doc's are 20 yrs old, you MAY have a huge project on your hands. ....and I LOVE those kind of projects!
A PLC is very well capable of outlasting it's "manufacturer", like Sy/MAX, T.I., GE, Allen Bradley.... Oh yeah, AB still supports all those oldies,,,, just like Schneider and Siemens and Fanuc do.
My bet is that 10 yrs from now AB will still be making and selling some SLCs, and along with the rest of the major players they'll be doing systems with a CPU unit and all I/O will be remote or "smart". PLCs direct, and a Chinese company will be making cheap "old style" PLCs, and you'll get one with 64 discrete I/O (10-300V AC/DC) and a bunch of high-speed timer counters, for $100.
Of course there will also be a Linux based "open architecture" standard by then......