Comunication and wiring

Good evening forum,

I was at a client today who has a simatic s5 plc (photo) and i need to monitor online the ladder diagram to see why his machine is not working.

My question is what is the program to comunicate with this plc and also what is the pinout from the cable?

Thank you in advance

Hello Jackaress;

S5 PLCs of the S5-100U family (like most of the S5 PLCs) used a programming port with AS511 protocol on a TTY (current-loop) interface. The cable proposed by Siemens to interface a COM port on a PC to these CPUs was the 6ES5734-1BD20 (see the screenshot below).

Getting this cable is already difficult, being that it is a spare part since 2000. And it is a 15-pin (COM Port) to 25 pin (CPU) cable, which means at least a 9 pin-to-15 pin adapter, and in some cases an additional gender-changer-adapter for the PC side. The cable ended being quite clunky in your toolbox...

As you can see for this discussion, the cable has a very old design, from the 1980s.  There are also difficulties in building your own adapter cable, or finding a USB-to-RS 232 adapter that works well with the adapter cable:

https://support.industry.siemens.com/tf//ww/en/posts/i-need-some-help-for-made-an-adapter-s5-100u-db-15-female-to-sinumerik-810-db25-male/54598/?page=0&pageSize=10

A very complete design for a RS-232 to TTY cable can be found here:

https://www.amsamotion.store/2019/12/pc-tty-wiring-diagram.html

I would suggest that for a more modern PC, which generally has no RS-232 port, but has USB connections available, you could look at this offering from IBH Softec; the USB-S5 cable. It works quite well, with Step 5 v7.x or with IBH Softec's S5 for Windows (a very interesting alternative to DOS-based Step 5) and it has the merit of being much cheaper than other solutions.

https://www.ibhsoftec.com/epages/63444704.sf/en_GB/?ObjectPath=/Shops/63444704/Categories/Produkte

Hope this helps,

Daniel Chartier