what so special about Allen Bradley?

[berserkfan]

http://www.ebay.com.sg/itm/Allen-Bradley-PLC-3-Keyboard-1770-FEC-Ser-Firm-G-A-/140516951718?pt=BI_Control_Systems_PLCs&hash=item20b77686a6#ht_1849wt_910

Asking price: $2.3k. It's obsolete, comes with no manual and accessories or whatever console it was supposed to work with.

Is that some kind of magical device, or is it of interest only to wealthy collectors?

[jcrouse]

AB, Allen Bradley, is big in the PLC, programmable logic controllers, arena. They make many automation devices. My old company, actually in the same town as the seller, used them in all the machines they built.

John

[jdcarpe]

It's not obsolete, just a specialized piece of equipment. It's a device for programming PLCs (Programmable Logic Controllers). PLCs are used in industrial control and automation. That device connects directly to an Allen Bradley PLC, and allows you to change the programming without connecting the PLC to a computer console.

[alka5eltzer]

I remember this bad boy years ago .. it was used with an Allen Bradley PLC 3 & 5 Rack Mount Industrial PLC system. That price isn't far off what it was new lol.

It was normally Mounted on to a Control cabinet with a CRT inside behind a glass panel... we used it to change programs or generally control the machine... the machine was the length of a Tennis court... beast of a thing it was.

[berserkfan]

I posted this, and within 10 minutes, the combined brains of Geekhackery have replied with so many edifying answers.

This keyboard used to control a behemoth the size of a tennis court? OK, at least I now understand why it costs so much.

But I don't really understand what a PLC is. Isn't that outdated already, since modern computers can be used to control almost everything? I'm just an ignoramus, please edify me.

[TheProfosist]

Specialized equipment, hardware, software, and technology is still used in most cases to run equipment on this or any industrial level. In many cases the hardware is quite old and very specialized when compared to current PC tech

[rootwyrm]

Specialized equipment, hardware, software, and technology is still used in most cases to run equipment on this or any industrial level. In many cases the hardware is quite old and very specialized when compared to current PC tech

Ayup. Old has nothing to do with it. Specialized and still in use is why it's expensive as hell.

What, you think when you're dealing with hundreds of tons of moving machinery that can kill a man, or explode, some desktop PC or x86 box is acceptable to control it? Yeah. No. These are systems which cannot and do not fail ever. Because when they do one of two things happen: you lose tens of thousands of dollars every second, or people die.  Making hardware that meets these requirements is very expensive and very complicated.

[OldDataHands]

Making hardware that meets these requirements is very expensive and very complicated.

On the other hand, back when I worked with Allen Bradley equipment, we had a saying for it:
"You can buy better, but you can't pay more."

[jabar]

I remember the storeroom in a friend's old AB office which had oodles of ancient computer equipment from the 80s (on top of all their industrial control samples)... that place was full of Model Ms. You can see some AB branded keyboards sold through clickykeyboards.

[rootwyrm]

Making hardware that meets these requirements is very expensive and very complicated.

On the other hand, back when I worked with Allen Bradley equipment, we had a saying for it:
"You can buy better, but you can't pay more."

Well, I didn't say A-B particularly met the requirements...