Allen Bradley History - Was there a PLC1?

CaseyK

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CaseyK
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I first used Allen Bradley PLC's in 1988.

PLC2's, SLC100's, and the "NEW" SLC150.

Were there any AB products before the PLC2 and SLC100?

My only source of PLC info at the time was an old Modicon guy. We learned AB together. All he new was the one model of Modicon that he had used.

Any AB oldtimers got some insight into their early products, and when they arrived on the PLC market?

thanks.....kc
 
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I worked on one of the predessors at Ford's Dearborn engine plant back in the mid 80s and for the life of me I can't remember the AB series number. I do remember that the cards had to have been about 18" tall and about 3" thick and could handle 8 points(?). I don't recall what the processor looked like but I know it wasn't a PLC2. It was an engine head machining line and it wasn't too many years later Ford replaced the whole line for a different model.

There was also a PLC4 around the same time as the PLC3. I took my first AB class in 1984 and trained on the PLC3s and I believe the 4s were already history. I worked on them briefly later in the 80s and you could set them up in a distributed fashion but it was very fragile.
 
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Yes there was. I am a little hazy on the details because it was before my time with AB. The CPU was an external box and the IO was on a parallel bus to enormous 4pt modules. The Bulletin No was 1774.

Some years ago I did a conversion at a tyre plant ( a Banbury mixer) converting and old 1774 CPU with 1771 IO to an SLC500 retaining the existing IO on Remote I/O. The evolution between the PLC1, through to the PLC2, 3 and 5 was quite obvious.

(Yes there was a PLC4, and I did actually see one in a bakery once on an imported dough mixer...but the PLC4 had a very short commercial life and was dropped in favour of the SLC100).

The other poster here who will know more about all this is Gerry, who really does know his older AB hardware far better than I do.
 
PhillipW, thanks for jogging the memory with the series number (1774). PLCCenter has a pic of what I remember seeing (or something similar:

ALLBRADLE-1774LP3L.jpg


It wasn't called PLC1, just PLC.
 
And of course the good old PLC3

ALLBRADLE-1775A1L.jpg


Still find them in automotive paint plants built back in the late 80s early 90s where redundancy was required and at the time AB only had it in the PLC3 (hot backup). The plant also required core memory which was outrageously expensive.

Please excuse the rambling.
 
The other poster here who will know more about all this is Gerry, who really does know his older AB hardware far better than I do.
Click to expand...
...granddad here...

I do remember that the cards had to have been about 18" tall and about 3" thick and could handle 8 points(?).
Click to expand...
You're thinking about the 1778 series I/O - I believe they were 16-point.

The CPU was an external box and the IO was on a parallel bus to enormous 4pt modules.
Click to expand...
The I/O was all "remote" and serial. A separate 'distribution panel' was used to connect to up to four chassis. There was a separate 4-wire connection for each chassis. A maximum of two distribution panels was allowed. There were adapters for 1778 and 1771 I/O (177x-AR).
The 4-point modules that Philip describes are the 1777 series that was introduced with the first PLC2's.

I never saw a PLC4, but I did hear about them.

Must of only been a handful made.

Must guys I've talked to never heard of them.
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Early 80's stuff. After building the biggest PLC (PLC3), they decided to make small ones. Cleveland came up with the PLC4 aka Microtrol?? and Milwaukee came up with the MAC (Modular Automation Controller). Neither one was very small (except in capability) and neither one caught on.

What's next? PLC6?
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There would have been, but it got re-badged as PLC5/250.
 
There was an early PLC called the black box mounter on a metal back plane with 8 bit IO cards and programmed using a Boolean Terminal
 
I remember and old rack system bulletin 1771 during the 80's, we used updoc for documentation, I don't remember if online programming was possible, only that to up/download to it a cassette tape deck was used.
I do remember the old T3 programming unit with exchangable keypad overlays.

Steve
 
Started with the GEC Gem 80 in the mid-80s, using the Black Box "portable" programmer, then the Yellow Peril Programmer but eventually I saw the light...

from 1988 : PLC5, PLC3 and we replaced a PLC3 with a PLC5/250 which was a scary beast. Eventually ControlLogix too...used AFE IC2X and IC2000 as well as DOS Factorylink.
Used ASCII cards for talking to the Dataliner DL40 and DL10, which took some programming.

Now many years later, back to many PLC5 systems, some Siemens S5/S7, Klockner Moeller PS3, SLC 5/03....DOS, WinNT, Win2000 with InTouch 7.0 upwards to 2014, and modern PLCs as well as Micrologix, CompactLogix and ControlLogix..
 
The plc4 was short lived for a reason.
This is from my distributor and I am citing what he said as best as I can.

The plc4 was a good plc as a stand alone unit.
The unique thing about this unit was that it could use the memory of other plc's. The problem was that when it was connected to other plc's, it used its memory and failed to tell that processor.

in short, the plc4 used a plc2, 3, or 5 memory, but they didn't know it and then wrote over that memory creating havoc in the plc4 code.

regards,
james
 
James Mcquade said:
The plc4 was short lived for a reason.
This is from my distributor and I am citing what he said as best as I can.

The plc4 was a good plc as a stand alone unit.
The unique thing about this unit was that it could use the memory of other plc's. The problem was that when it was connected to other plc's, it used its memory and failed to tell that processor.

in short, the plc4 used a plc2, 3, or 5 memory, but they didn't know it and then wrote over that memory creating havoc in the plc4 code.

regards,
james
Click to expand...

I was involved with some PLC-4 jobs back in the 80s used for grinders re-manufacturing bearings. IIRC, we used 3, one just to handle the servos. They were unique in that they featured distributed processing, hence the shared memory between CPUs. The grinders shipped somewhere deep in China. About 4 years ago the OEM was asking about getting some support for one of them (still running after all this time) but the lead engineer had long since retired.
 
No one said PI

Remember the AB Pyramid integrator? Or was that also the PLC5/250.
As for old AB - T1 terminal and PLC2 with tape backup is as far back as I go. But I did convert A GEM 80 to PLC5 for AB as a sub if that is older.

How about the old AB HMI's advisor. Drawn in pixel level with a whole 5 meg of disc space and running at 6MHz, I did some of them
 

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