Profibus - S7 How to get a db


Thread Starter


Hi ?
How can I get a db throught the S7 API by siemens.

The OPC can get a db throught the s7 but I can´t see how ?


Sharad maheshwari

Dear Alex,
You could use the OPC to get the DB. You will have to use Windows NT 4.0 with SP5 and above as the OS in the computer or Windows 2000 SP1 . The PLC S7 will be the OPC server and your application package (HMI) will be the OPC client.

Assuming that you will use the TCP/IP protocol with the standard Network card of your PC and you will need the following two software which are the part of Simatic Net CD and is free:-

1.) Industrial Ethernet--Softnet-S7 ver 3.3
2.) OPC server Ver 2.2

You will need the license for the software industrial Ethernet Softnet S7--ver 3.3 which is at a cost.

Now you will have to install both the software and then you will get a Icon in the Control Panel Of Windows OS by the name "Setting the PG/PC interface". Here you could choose the TCP/IP protocol using the ADD symbol. Here assign an IP address to the card you will plug after power shut down.

Check for the card functionality after installation. You would have already assigned an IP address to the S7 system. In the run command please type 'dcomcnfg'and choose Simatic OPC server.

The software installed will have a entry by the name SIMATIC in the Start Menu. In this under the Driver package you have a software tool by the name COMS7L here you will define the host and remote IP address and then create the binary file. This binary file has to added in the Card settings and OPC package setting.

Connect the cable and run a add-on tool by the name OPC scout to check for the connections between the PC and S7 device by add items under a group with the address of the DB you want to read.You can now use this address in the OPC client package of yours and check.

The above procedure is explained on the Siemens Internet site under A&D product support FAQ's. They can be seen all around the world. Once you reach the product support site there you have to choose for HMI and in the PROCESS VISUALISATION :WINCC and under this COMMUNICATION and it has an FAQ stating " OPC communication between WINCC and AS". Here WinCC is an Siemens HMI and you could use your application instead of this.

You could contact your local Siemens partner for the FAQ print out as well.

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