Data collection from Siemens SIMATIC S7???


Thread Starter

Pavel Horak

I'd like to collect the data from my PLC (SIMATIC S7, MPI protocol). Not too many, max 20 variables. The collected data should be stored and than when the remote PC will be connected downloaded into the PC. I don't want (I cann't) to use a standard PC (price, hard disk,) as HW for data collection. I'd like to make a simple solution with minimal HW and SW. The SW for data collection management I'm able to write by myself (C, C++, VB). But I need to use some 'interface' SW for MPI probably. Could somebody recommend me HW and SW suitable for such application?
I may help you with alternate solution but need that you answer this questions:

Which S7 PLC are you using? S7-200, S7-300 or S7-400?

Are you need collect 20 samples or many samples of 20 variables?

How many byte or kbytes you will for the storage? what data type need you to collect float, uint16, int, etc.?

How many bytes or kbytes of memory your PLC program use?

Luis Rios
[email protected]
One such 'interface' that comes to mind is SIMATIC Computing. This is an ActiveX control that has an access point added to the PG/PC
interface (MPI/Profibus or TCP/IP). This control has various read/write methods that a user can evoke inside VB or VC++. Of course if you
have a TCP/IP module you can use winsock. Hope this Helps.

Roger Hill
Software Geek
If the information is more important that the media storage you can use a old serial printer and make a PLC program that print the data
stream that you need. For a S7-200 it is easy because you can use the FreePort mode for put the data byte through port and Siemens have
many application notes that explain how do that. For a S7-300 and above you will need to use the MPI protocol. I know a source of
information about MPI in "": that you may use for you application. The MPI information in not complete but maybe is the unique tha ones can find until now.

If you have enough memory you can storage the data in the PLC memory and periodically download it to PG/PC using STEP7 and the porting to
Excell. What you must do to export from STEP7 to Excell is explained in

Use a PC is more easy because there exist many tools that you need for your application, but you have written that you can't use one.

The above sugestions are not so elegant but i think that is better than no solution.

Luis Rios
[email protected]