Capturing a DOS program from a 486

[mad4x4]

Impressive !
I sometimes ask customers for a video of the PLC IO when they cannot otherwise describe what is going on. Takes some effort, but surprisingly effective.

That sounds as an early Beckhoff software PLC.

And no outputs ? Does sound more like a datalogging PC.
Looking at the photo, it appears to be a mess, but clean. I have seen worse.

If its beckhoff then there is a good chance that you can get parts from Beckhoff for it. Hans Beckhoff has the philosophy of if we supplied it we can still supply it.

If its is a Beckhoff PLC then they will even have software for it.

 

[5618]

That looks like a STD (Simple To Design) backplane I know from the Polaris bagmaker. A bit of Google led me to a list of STD boards that seems to have some descriptions of your boards: https://www.gdca.com/products/bus-type/std/

 

[GaryS]

First you say it’s a DOS program well DOS is (Disk Operating System) the computer runs on that system, the program you want to dump in most likely Basic 6.0 That is just a ASCII file and it can be transferred or printed out whatever you desire.
Modern Windows based computers ( Panelview ) run on Windows operating system and they don’t like running the old Basic programs.
In your case I would just start over as if it were a completely new project with a newer currently available PLC. With a small Press you may be able to get away with a Micro 800 series controller. There are many options available to select for the HMI. So give it some thought figure out what your needs are and don’t forget to think about ant additional features you would like to add to enhance the operation. I have upgraded more than a few older system and I can tell you in most cases it better to just start over as a new project the outcome will be a better system

 

[Puddle]

Impressive !
I sometimes ask customers for a video of the PLC IO when they cannot otherwise describe what is going on. Takes some effort, but surprisingly effective.

That sounds as an early Beckhoff software PLC.

It wasn't perfect and took a few tweaks, but gave us enough of an understanding of the machine to blunder through from there. I was worried that there would be a pile of functions on the original controller that weren't used regularly and would therefore be missed so I kept it with the intention of extracting the original program. Unfortunately I never found time and decided to throw it away after the new controller had been running for about a year.

 

[mikeexplorer]

Brings back memories of a project I did years ago. Using a Tandy Color Computer 3 I built an environment control system by adding PIA chips to the address bus to have additional I/O. It controlled the temperature and daylight time of reptile cages and adjusted automatically for the time of year. This is going back to 1997 - 1998. The program was written in Basic09



Nowadays doing this with a PLC would be easy

 

[JesperMP]

If its beckhoff then there is a good chance that you can get parts from Beckhoff for it. Hans Beckhoff has the philosophy of if we supplied it we can still supply it.

If its is a Beckhoff PLC then they will even have software for it.

You are responding to my post. I was responding to Puddle in post #11.
ceilingwalker probably do NOT have a Beckhoff system.
All we know is the photo and this quote:

Looking at my pics the only input I see for sure is a pressure transducer input.

I am not convinced that the PC controls anything.

 

[Ken Moore]

I did not work on it, but once saw a gantry palletizer system that ran on a PC with Opto22 I/O. Late 80's early 90's. So it is possible.

 

[parky]

I once re-hashed an old wrapping machine, the "PLC" as such was a Zilog Z80 processor, it was a single board system, the customer managed to contact the original installer, he told them the company who manufactured it made their own boards, however, he was able to send me some drawings so it was easy to see what the I/O was, the original company no longer traded & the customer wanted some extra functionality, I replaced it with an S5-95U had it running in about 16 hours including writing the code. I have done a number of upgrades to existing bespoke systems ranging from relays to PC based or bespoke controllers & it is often better to start from scratch, however, having drawings makes it a lot easier. One of the worst was a cutting press with 9 cutting programs, it was all relays probably about 100 + my boss took the project on but we could not find any documentation & the operator who used to run it had retired & moved abroad, no one had any idea how it worked, the only thing we managed to find out was some idea of the programs from very well worn out switch labels & we guessed the rest based on the order we could see how the patterns seemed to work.
The biggest problem was a replacement hydraulic solenoid system, the replacement unit supposed to be identical the ports were out by quite a bit, we had an adapter plate made, struggled to get it to work until we found out that because it was some form of multiple hyd feed solenoid system the porting was different, turned out it was just a matter of moving grub screws on the ports to get it to drive the relevant valves, this was on new years eve, ended up there till 4:00 in the morning so missed the celebrations.

 

[drbitboy]

If you do not have the source code, it is impossible to know how the programming works.

While this is practically true i.e. effectively true in most situations, it is not absolutely true and depends on the intensity of the motivation. Cf. here: https://social.hackerspace.pl/@q3k/111528162462505087


[Update: maybe that topic is worth starting a new thread? I clicked the link to the report in Polish, and Firefox translate provided a very readable result.]

 

[lfe]

While this is practically true i.e. effectively true in most situations, it is not absolutely true and depends on the intensity of the motivation. Cf. here: https://social.hackerspace.pl/@q3k/111528162462505087


[Update: maybe that topic is worth starting a new thread? I clicked the link to the report in Polish, and Firefox translate provided a very readable result.]

The one in the link says to reverse engineer a PLC program, not a PC program running in DOS

On old and not so old PLCs there was a direct relationship between the content of the PLC memory and the program instructions.

Probably there is no need for reverse engineering, just download the contents of the memory and you will already have the instructions.

It is very different if you only have an .exe file generated by some compiler using a high level language like Basic, C, Pascal etc. which also calls other low-level routines, normally supplied by the I/O hardware manufacturer, to manage the input/output cards.
Languages that were not invented for automation.