Transferring Data between a PC and S7

[jholzer]

Hi! I´m totally new to S7 and have the following problem: From a custom-GUI I need to transfer some data between a PC (with Step7-Software) from a custom GUI (written in C++) to a S7 and one or more controlers connected to it. In detail I need to access the OB1, FBs and DBs to "find" my datablocks I want to manipulate, the overwrite one DB and set another bit in another DB. Also I need to query some variables in other DBs for current values. But I have no idea how to do this! So I read some post in this forum and found some hints to access the data, which is stored wihtin the Step7-Software using "SimaticClass", "S7Project", "S7Program" and "IS7SWItem". But I didn´t manage to get or put live-date to the S7. I would appreciate any help that I can get to connect my GUI to the S7. Thanx a lot! J.

[JesperMP]

Hi jholzer I do not exactly understand what you want to achieve. Why do you need to "access the OB1, FBs and DBs to "find" some datablocks" ? Do you not know in advance which DBs to access ? The other problem is how to access the data. Are you on a shoestring since you want to access the ActiveX objects that you only have on a PC with STEP7 ? The normal is to purchase some kind of comms library. There is Simatic Softnet from Siemens (OPC interface), which require one license per installation. There are 3rd party software from Deltalogic, IBH and others (OPC, ActiveX or DLL interface). Some require a single license per developer, others a license per installation. And there is the free open source software LIBNODAVE.

[iic_hyd]

Hi, It is very easy to access all the data blocks online with simatic manager and a S7-300/400 PLC but I couldt understand what exactly you want to read or write to or from PLC by using Simatic Manager, Pleae let us know the PLC Model Simatic manager Version and also a copy of your ladder if it is possible. Regards N.Subrahmanyam iic_hyd@rediffmail.com