What is the oldest PLC system you have running?

The strangest thing was a control system made out of logic blocks (kinda like Lego blocks) with each block having an OR-gate, an AND-gate, or a timer. A nightmare to troubleshoot !


JesperMP


Were these MTE (I think) blocks that stacked on top of each other with screw clamp connectors sprouting all around, about the size of a cigarette packet. They stacked on breakable metal rods, if one failed in the middle of the stack then you had to disconnect everything above and slide them off to change hteone that had failed. I hated those.
 
SLC-100 2 expansion racks, just retired late last year.
Shark PLC retired in January
5-TI series, 2 retired one still in service. retiring in 3 months.
PDP-11 still in service. retiring in 3 months.
3 PLC 5-35 systems still in service.
 
Originally Posted by JesperMP View Post
The strangest thing was a control system made out of logic blocks (kinda like Lego blocks) with each block having an OR-gate, an AND-gate, or a timer. A nightmare to troubleshoot!

That reminds me of Cincinnati Milicron Mold Presses. If you wanted to change the logic you had to get out the wire wrap tool.
 
JesperMP
JesperMP said:
The strangest thing was a control system made out of logic blocks (kinda like Lego blocks) with each block having an OR-gate, an AND-gate, or a timer. A nightmare to troubleshoot !
Were these MTE (I think) blocks that stacked on top of each other with screw clamp connectors sprouting all around, about the size of a cigarette packet. They stacked on breakable metal rods, if one failed in the middle of the stack then you had to disconnect everything above and slide them off to change hteone that had failed. I hated those.
No was different. I dont remember the brand now. The system I remember was with little grey blocks 5mm x 20mm x 10mm, with the pins on one of the thin edges. The pins plugged into connectors that were soldered onto a circuit board. Worst time I had to try and fix one of these systems were when there was a hairline crack in one of the copper circuits on the circuit board. Intermittent error that only showed up at certain temperatures. And it was near impossible to get access to measure anything. And of course the logic was inverted (signal high = off), but that was the least inconvenience.
 
ianingram > I visit a site where they have a 1756-L1 processor, connected to a SCADA computer that is running RSview (can't remember exactly which version). The computer has windows 2000 as the operating system, which pre-dates Windows XP.

I think that it was installed around 1998. The PLC has version 8 firmware, and the PC also has RSLogix 5000 version 8 installed on it, so I can see the program file ok (for now), however this version cannot be installed on a new computer - and I don't want to risk a firmware upgrade.

>>>>

Ian,
First thing I would do is create a ghost image of the computer. Restore the image to
another computer (capable of Win-2000). Get the Windows 'fixed' so it runs and that should carry everything across - RSLogix 5000, RSLinx, and that precious license.

I did that to an IBM thinkpad. When the Thinkpad died, I was able to put the image on another (old) laptop and get it running. Including that funky card for allowing the laptop to interface with a PLC5/15. I still use it to access PLC-5, SLC, and an RSLogix 500 PLC.
Poet.
 
We have a whole building (commissioned in the mid 80s) with all the critical HVAC being controlled with TI-505 hardware (20 PLCs); the HMI is Intellution, running on a pair of NT4 boxes. We are slowly replacing them one by one with ASIC building automation hardware, with a pair of Schneider Tri-GPs to control the chiller plant. Migrating to Citect for HMI.
 
Originally Posted by JesperMP View Post
The strangest thing was a control system made out of logic blocks (kinda like Lego blocks) with each block having an OR-gate, an AND-gate, or a timer. A nightmare to troubleshoot!

That reminds me of Cincinnati Milicron Mold Presses. If you wanted to change the logic you had to get out the wire wrap tool.

Someone beat me to it. I wasn't sure if these were classed as PLC. We had several at my previous employer. Got a 1000 tonne "new" to us in early 2000's.
Mechanic and I spent 2 days troubleshooting a fault. You know how it goes...

Us: "Operator what happened the machine was running great."
Operator: "Nothing, it came closed then stopped."

After much head scratching the first day trying to read the prints we had, the second day became a jumper it out and and eliminate. Come to find out this machine, unlike our other smaller Injection Molders, had a pressure switch when clamping up, before it would continue its cycle. Someone had adjust the pressure valve, so it appeared to clamp up but then lost tonnage.
When both our managers came down to see what was going on I asked "can we change it to a PLC?" Right after that production run I was given 2 weeks to rip out the old and replaced with an Automation DL440.
 
Work for an Integrator all the plants that we support are finally up to CLX - L61 is the worst processor we have, and any new plants get the same treatment.



It's really nice :)
 
I installled dozens of FX on earlier 90s and also some big modular A Mitsubishi series,


The Mitsubishi A series are bullet proof.
Installed loads 25 years ago and they are still chugging away 24/7

Changed some relay output units but that's it.
I have some replacement Q series programmed and waiting, gathering dust but as they work 24/7 they don't want to do it until they have to.
 
The Mitsubishi A series are bullet proof.
Installed loads 25 years ago and they are still chugging away 24/7

Changed some relay output units but that's it.
I have some replacement Q series programmed and waiting, gathering dust but as they work 24/7 they don't want to do it until they have to.

Wait until they hit 30 years old. They start biting the dust. Regardless, 30 years is nothing to scoff at. They're not PLC5's, but they're pretty solid :ROFLMAO:
 

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