Buy a 36-year-old programmer in 2023 and not experiment? In the article, we will consider the stages of restoring the functionality of the Siemens Simatic programmer, see the main nodes of the hardware component, and even install the MS-DOS 2.11 and CP/M-86 operating systems.

Below is an overview of the programmer, photos of retro boards, stages of prevention, the inclusion procedure, photos and videos of downloading operating systems.

Welcome. 🙂

Brief content.

• A bit of history;
• hardware analysis, keyboard, prevention;
• inclusion;
• Installing MS-DOS 2.11;
• Installation of CP/M-86;
• Conclusions.

❯ A bit of history

According to

Wikipedia

the device described below is a PLC programmer (the abbreviation in translation means – controller with programmable logic).

Information from this source was emphasized during the writing of the article.

I was upset by the phrase, I quote: “This machine is NOT compatible with PC, so it is not used.

The programmer was purchased at a well-known flea market. At the moment of transfer, the owner put “this suitcase” in front of me with a roar. I shuddered to know the contents: old MFM hard drives are especially afraid of shocks. The only thing that reassured me was that the device was turned off, and the hard drive heads were parked.

❯ Hardware analysis, prevention

Constructive execution of the monobloc programmer with a folding QWERTY keyboard.

The beginning of operation was cleaning electronic components from dust by blowing and brushing. To avoid damage to electronic components by static electricity, blowing was carried out in the bathroom due to the presence of light humidity. Then the device was transported to the country and blown with an industrial compressor.

On the back of the case there is a forced cooling fan. A look at the other components of the rear end below.

The real-time clock and calendar use two power cells that date back to 2004.

Unfortunately, from time to time, the flow of electrolyte and oxides got into the battery compartment, but fortunately – it turned out not to be terrible, the battery compartment is isolated from other electronic components of the system.

The disassembled battery compartment looks like this:

The components were cleaned of oxides – a dremel with a metal brush, the contact areas were completely tinned, and new wires were soldered to them.

And everything is assembled in reverse order:

Inside the programmer consists of blocks that can be conditionally classified by purpose.

CRT unit (electron ray tube) with accompanying electronic board. Monochrome display. An interesting feature of the display was noted – when it is turned on, the flicker frequency does not interfere with its photography, there are no stripes.

The power part of the power supply unit is located in its own housing to avoid electric shock:

The connecting (motherboard) board and TEZ modules (typical replacement element) are installed to it. Securely fixed with a rocker from sliding out of the slots:

Here, in fact, pay.

The board containing the RAM is represented by the dipp chip set km-41256 with the possibility of expansion. The photo shows an empty bank, free panels.

Board with Intel P8088 CPU and ROM:

A board containing peripheral chips:

Storage controller board:

And a nice chip closer:

On the back of the boards, you can see the jumpers made by hinged assembly, which indicates manual “proofing” of the boards:

All the key chips (CPU, ROM) installed in the collet panels (beds) were carefully pressed into place to avoid slipping over time. 4 free connectors for expansion boards were found on the motherboard:

Connector of the front panel of the programmer:

As I mentioned at the beginning of the article, the programmer is equipped with an MFM-accumulator made by Tandon, model TM252. According to the sticker with the make and model, the capacity of the disk is 10Mb, the size is 5.25”.

and FDD, for writing 5″ diskettes, with a capacity of 720KB:

The back of the programmer contains a number of interfaces, a button and a power connector, as well as a connector for connecting a monitor.

Interfaces include V24, RS-232 (Recommended Standard) serial port interface in db25 connector design and db25 printer port.

I made conclusions about the date of the device (exemplary) based on the date markings found on the soldered chips (the chips in the panels could be changed later). They date back to 1987. After physical prevention, the boards are carefully installed in their places.

The keyboard of the device has a QWERTY layout, it looks very nice and attractive – rounded buttons with soft pressing and a color range of functional keys indicate a well-thought-out design. I want to work on such a keyboard. Due to the construction of the case and the fact that the keyboard hid its buttons when folded, they have survived to the present moment in good condition.

❯ Enabling

The programmer is turned on by the power button located on the back of the device. There is no BIOS as the usual configurator. Changing parameters and diagnostics is carried out using a 5.25″ diskette with a system utility.

When you press the skip button immediately after switching on, you get to the test menu:

For the initial boot of the operating system, “Disk A” is polled for the presence of a system diskette. In its absence, the hard “Disk B” is referred to. When the programmer was turned on, the screen lit up with the following inscription, indicating the absence of an operating system on the hard disk:

I did not have system diskettes. For conducting experiments, a new box of diskettes with a capacity of 360 Kb was purchased:

Two operating systems were tested – MS-DOS 2.11 and CP/M-86

❯ MS-DOS 2.11

The MS-DOS 2.11 system disk image found on the Internet 211PG685.DSK was 737 KB in size, which exceeded my 360 KB floppy disk. I had to hastily assemble a computer with a 5.25″ disk drive with a capacity of 1.2 Mb, capable of formatting and writing diskettes, including 720 Kb. Using an auxiliary computer, the 360 ​​Kb floppy was formatted to 800 Kb by the format command with the specified parameters and the resident pu_1700.com utility loaded:

Then the image was written to a diskette using the rawrite2 utility.

rawrite2 -f 211PG685.DSK -d a:

Booting from drive A was successful.

Next, the procedure for creating a single partition of the hard disk in its entirety, in one volume, was launched:

The next step is to make the created partition active. You can see the status change from Passive:

On Aktiv:

After creating a hard disk partition and making it active, a final formatting procedure is required for further use. The duration of formatting was 5-7 minutes. Decent considering the volume.

Downloading the programmer from MS-DOS 2.11 was successful.

❯ CP/M-86

The CP-M/86 operating system was loaded using a system diskette.

Deployment of the diskette image was carried out by the following command.

rawrite2 -f cpm86.img -d a:

After creating the system diskette and subsequent booting, you can install the operating system on the hard disk.

Results of installed OS CP-M/86:

After the programmer is finished, before turning it off, it is necessary to park the HDD heads with the HDPARK command. The resulting message indicates a potential transport.

The work is completed, you can turn off the device.

❯ Conclusions

The programmer is an industrial and specialized device, and although there is information about incomplete MS-DOS compatibility (at the beginning of the research I did not know about this), in the future you can try to install simple, old, but nostalgically attractive retro games. Such as, for example, Digger, Sopvich, Tower, and I think of Prince of Persia, I definitely remember that, albeit slowly, it worked on the XT architecture. System requirements, the presence of an Intel P8088 processor, a sufficient amount of RAM of 512 KB and the presence of a 10 MB storage device allow us to hope for this.

One of the goals of the article is to organize and record one’s own knowledge, as well as to collect comments with hints in which direction of non-target use this device can be applied.

In general, the feeling after using the programmer is approximately as follows: everything in this device is excellent, starting with the quality of performance and ending with the wonderful sound of loading the MFM hard drive (I heard it on the video, I tried not to make noise). As if I had visited in the past.

Thank you for your attention.