What do I need to talk to a AB PLC-3?

I've gotten a call to go out in the morning to a new customer and download a program to an Allen Bradley PLC-3. 3rd-hand intel says:
1. The PLC "Lost it's memory"
2. They have a backup on diskettes
3. They have the programming software on diskettes.

I'm trying to do my homework but it seems this stuff is so old, there is not much info floating around to read. My investigation suggests the correct software is called 6200-PLC3. Correct?

What are the system requirements? I have VMWare but never tried running DOS in it. Do I need an XP VM running a Win 3.1V VM running a DOS box? I don't even know where to start. What version of DOS does it need to be?

What cable do I need? Research suggests 1770‑KF2 which appears to be a box bigger than a phone book (ironic reference to other obsolete thing). Can't I just make a serial cable? I can't find a pinout.

Any pointers greatly appreciated!

Alternatively, if anyone has a speech prepared for "the Big Letdown" where you have to tell a customer that his precious moneymaker has exhausted all 9 lives, I'll take that.

now you are trawling the memory banks...

IIRC the PLC3 is "usually" on Data Highway, which requires the 1770-KF2 to convert from DF1 to DH...used to love these boxes way back in the late 80s, then I discovered companies still using them about 6 years ago..

if they have the software on diskettes, they may be 5 1/4" diskettes, if lucky they will be 3 1/2" floppies

surprised if they don't have programming facilities.

there are others on here better qualified than I am, so hopefully they can help..

I ran DOS on a VM but had issues getting files in and out of it as you can't map a folder in your native hard drive. I'm thinking now and I'm sure I would have tried a USB stick too... but can't say for sure if I did however the result was the same. This being said, I didn't spend too much time on it as it was more of a proof of concept for a colleague of mine than for me.

As for the speech, get the actual date that Rockwell discontinued the product, mention that the PLC family that replaced PLC3 had a long life of 30 years or so and that too has been replaced and leave on a positive note by highlighting that the replacement today will be far cheaper than when it was installed as a lower range CPU nowadays can do the same thing as the PLC3.

PLC-3 had no onboard serial port. You need a computer with an ISA-slot DH+ card, or a serial/DH+ interface.

There was the desktop style 1770-KF2, as well as rack-mounted 1771-KE and 1785-KE. You would use the RS-232 DF1 driver in the old software.

But... anything newer than Windows NT or Windows 2000 is very unlikely to let the serial port drivers on 6200-PLC3 or AI-3 (the ICOM version) connect to serial hardware.

Ask some question about their engineering workstation; maybe they lost it at the same time as the PLC-3 crashed, or it failed before. I think you might find that they lost their engineering capabilities about the time they stopped paying their local gray-haired guru's invoices.

If I had your problem here . . .

I'd go looking for a very old PC. One with floppy drives - both 5-1/4 and the 3-1/2.
And the DOS operating system . . . Plan on taking apart the floppy drives, and cleaning
and lubricating them. Also get some spare floppy disks so you can test out the
drives.

I'm thinking it might be possible to get away with windows 95 . . . . But that would be
determined more by what software you can find that can communicate with the PLC-3.

If I'm understanding what other, more knowledgeable folks have already said, it
will also be necessary to acquire an interface card for the computer.

Poet.

DosBox worked for me in the past for Dos programs communicating to PLCs. Not a PLC-3 though! Enjoy the trip to the museum.

Or, Go looking for a 1784-T45 Portable Terminal. Allen Bradley type.

I know of one (which will not be sold or let go of . . .) Which runs DOS and
has something called '6200 Programming Software' on it. This rig says it
can do PLC-2, PLC-3, and PLC-5 PLC's. It has a 3-1/2 floppy disk in the side of
it and a cable 1784-CP 96746402 is used to connect it to a PLC-5 (still in use -
which is why 'they' won't let the beast go).

Poet.

way back when - I used to work for an Allen-Bradley distributor - we kept a couple of the old "programming terminals" on the top shelf ... we'd lend them out once or twice a year to customers who had a desperate need ... you might try asking - if you're on friendly terms with your local reps ...

good luck with your project ...

this was one example.....if you see one, blow the dust off and crank the starting handle.....

strantor said:

Alternatively, if anyone has a speech prepared for "the Big Letdown" where you have to tell a customer that his precious moneymaker has exhausted all 9 lives, I'll take that.

Click to expand...

IMHO, I think that you have to go down this path.
I had to recently, and it was with much newer hardware.

At one customers' site that I visit, the building had been hit by lightning. A Mitsubishi PLC survived only because it ran off a 24VDC Power Supply, and the 240VAC/24VDC power supply died instead of the PLC.

On another machine, a Micrologix 1500 PLC that had 240VAC connected to the base unit also died. Apparently, these are not made anymore, so we cannot purchase new units off our distributor.
I guess that we could have tried eBay or something similar, but my boss made the decision that we could only offer a new PLC (Micrologix 1400) and the customer agreed (he was a bit more than desperate to get his machine going again).

Ian

The PLC-3 have an RS232 serial port for programming
it's a 25pin din on the front of the processor I use a 9pin to 25pin null cable
Also they can be configured for up to 4 Remote IO or 4 Data highway or a combination of them. You have to get online to see the channel configuration.
Also the original programming terminal has no provision o upload and save the program they are for online programming only, they used a tape deck to save the programs.

Good Luck

The AB PLC software only runs in DOS or a VM DOS machine

Gary's right... I was mis-remembering elements of the PLC-2s unusual port. We always used a 1771-KE to go online with them.

The PLC-3 is a monster even for people familiar with the old controllers. A plant where they've lost their program and their engineering tools runs a very high chance of not having the correct program backups at all, so "just come and load the PLC" can turn into "spend a couple weeks getting the control system running" in a hurry.

Good luck !

GaryS said:

The PLC-3 have an RS232 serial port for programming
it's a 25pin din on the front of the processor I use a 9pin to 25pin null cable
Also they can be configured for up to 4 Remote IO or 4 Data highway or a combination of them. You have to get online to see the channel configuration.
Also the original programming terminal has no provision o upload and save the program they are for online programming only, they used a tape deck to save the programs.

Good Luck

The AB PLC software only runs in DOS or a VM DOS machine

Click to expand...

Aren't channel config, etc. available via the front panel keypad and display?

OP - it'd be nice too to know whether they have a mode switch on hand.

This customer needs to work quickly to get that PLC-3 replaced with something newer. The last time I saw a 3 was in the dumpsters behind the Rockwell office north of Detroit - about 15 years ago.

There are handful of PLC-3 controllers still operating in my region that I am aware of.

One was scrapped when a local paper mill was closed and decommissioned. It was intentionally run well past its service life because of the mill's imminent demise.

Another is running on purpose in a bigger, better mill because they have chosen to migrate all the PLC-3 functions into their growing DeltaV DCS. All those projects are at least ten years behind schedule, but I'm not the one who convinced them to go DeltaV.

Another is running on Johnston Atoll in a closed loop incinerator system. Don't look for those parts on eBay unless you own a Geiger counter.