S7 PPI cable Connections

hi
Can anyone tell me the pin connections of the S7 Siemens PLC Pin connections. I need to develop an interface to the Com port of PC.

fahim

MPI/PPI/Profibus/Serial

I'm assuming that you're wanting to use the MPI port on an S7 PLC. This is not a serial port but is RS485 with the MPI protocol. If you're wanting to talk to a com port on a PC, you'll need a serial module for the PLC, though this will not allow you to poll or poke data directly on the PLC. To use the MPI/Profibus port on an S7, you would need an interface card for the PC plus you'd have to setup an OPC server, which will allow you direct access to the memory on the PLC.

Missed the PPI part

I missed the PPI part in your subject line. Even if you have the adapter to link your PC's serial port to the PPI port on the PLC, you'll still need Siemens OPC software to grab data off the PLC.

Fahim,

Remember not to directly connect your CPU to the PC serial port so as not to damage your PC's port because of the difference in voltage levels between the two ports.


Cheers
Hagos

The PPI issue has been handled already in this post. MPI pinouts can be found in this and this posts. All were found using the search function of this fine site. The last one is very interesting, because it shows what the consequences are when using the wrong cable.

Kind regards,

Thank you very much to everyone taking the effort to reply.
I am very grateful to all of you.
what I really need is just a PPI cable to connect my Laptop to the S7-200. I have the V3.2 siemens software to load logic programs into the PLC, I just lost my cable and cannot find a new one in the local market. so I thought instead of buying a new one why not just build onr for myself.
I understand that I need a RS232 to RS485 converter. was just wondering if my HONEYWELL Converter would work or not though the connections are different, and maybe the Honeywell converter is not RS485 most probably its RS422 ( this one I made for myself too...)

best regards.
Fahim Baig
Kinetics Engineering

Take into account - PC/PPI adapter isn't a stupid RS232/RS485 converter... It's catalogue price is 119 EUR. Even with delivery it will be cheaper for you...

Gambrinus said:

Take into account - PC/PPI adapter isn't a stupid RS232/RS485 converter...

Click to expand...

Indeed, it isn't a stupid one, it's a data-driven one. I have communicated with an S7-200 using an Allen-Bradley 1761-NET-AIC, which is also a data-driven RS232-RS485 converter, simply because it was available and the S7-PPI interface wasn't. It's something completely different when you're talking MPI.

Kind regards,