MS-Dos SCADA on Pentium M platform

Good day all,

I'm looking for a ideas here - I have a customer with an old spiral freezer which is run by a Siemens S5. The operator interface for this is a DOS based package and custom built panel which emulates a keyboard for the PC. The industrial PC which was on this unit has finally let the smoke out and my customer is looking for a fix. Finding a working industrial PC with a 486 processor isalmost impossible so we are trying to do a work around with a new Pentium M IPC.
I have a Bernecker + Rainer PC which has a Intel Pentium M, 1,400 MHz, 400 MHz FSB, 2 MB L2 Cache.

Using a CF card I have loaded MS-Dos v6.22 and the custom SCADA package and all appears to boot OK.

The problem I have is that for some reason it does not communicate with the S5 serial port. We are using Com 1 which is the same as the old PC and I have the com set to the default setting of 3F8, IRQ4 but even if I set this to auto we still have no communications.

What I am begining to think is that there is an issue between using the older 16bit architecture and the newer 32bit system.

Any ideas / thoughts etc would be appreciated

Thanks

I would suspect you have a UART issue but I am not an expert.

If you get no responses etc, It may be worth installing XP and then creating a MS DOS virtual PC using say VM Ware or DOS Box. XP will then handle the serial port side.

Cheers

No answers for what you want but might be of use.

My understanding is that a 486 processor was a 32 bit architecture

This Wiki Link seems to back it up
http://en.wikipedia.org/wiki/Intel_80486

What is the HMI software package used.
The Keyboard what brand is it, sounds like an item we also have.

I may still have a workable ordinary PC that has a 486 chip, that we have kept stored until we are rid of all PLC,s that require DOS to run the PLC software.
In two weeks the last one is scrapped all going well a 25 year & a 29 year old PLC.

If its worth your while or you are interested let me know and I will see if its still a runner.

Hi Gil,

Opp's I stand corrected - read the Wiki.



The old "PC" is a Siemens PC32M which probably doesn't mean much but when you whip the top off it has a 486 chip clearly visible and runs off an IDE HDD.

Apparently I am told these were originally developed for some fighter aircraft but this one ended up in a freezer.



The keyboard is a custom built touch panel which provides arrow keys, tab, F-keys and numeric input to the PC. This can be substituted for a standard keyboard (AT or PS2) which works fine but may not last the wash down procedures



Thanks for the offer of the 486 & I may get back to you on that but for now I would like to see if we can use a new IPC. I have just downloaded DOSbox so will try this with WinXP and see where it gets me.



As an aside it is amazing just how many 30+yr old PLC's are still ticking away in various plants. On Tues I was stressing to a customer that it would be a "Good" idea to replace the old Omron S6 PLC he has running his main conveyor which was installed in the early 1980's - he’s "thinking" about it !!

I have an older program that was written in QBasic and runs on Pentium class machine now. It was originally ran on a 386. My program also had issues with the serial port, I found that the problem was timing. Compared to new processors, the serial ports are slow. So the software was going so fast on the newer processor, it was not getting the serial input.

I purchased software to slow down the processor, it can also disable FIFO buffering on the serial port (another potential problem)
http://moslo.info/deluxe.asp
Your problem may be different, but it might be worth trying, price is very reasonable.

Are you sure that you're using the same config.sys file? You might look for DOS utilities or other ways of testing the serial port. You might also disable COM2 on the new machine.

It's also possible that buying a serial card for your PC might help if it's an internal issue. Cards seem to overcome a lot of "internal" things.

Problem Solved

To all - thanks for the ideas - In the end we disabled all other com / LPT / LAN ports on the PC using the BIOS. Then added the MOSLO software to the DOS and using this disabled the L1 Cache and the FIFO buffer for the UART.

Everything is now humming again and probaly good for another 20yrs (assuming the S5 keeps ticking)