Communication with Siemens PLC

Question

Soon I will be developing an interface with Siemens PLC, model ET-200A.

This is a new subject for me and here I am with some doubts.

Has anyone ever dealt with that kind of communication?
The communication is the same for any type of Siemens PLC?
Does the PLC store as information inside it? It has a database?

The idea is to develop in C#, collect the PLC information and persist it in an SQL database. The persistence part is pretty quiet for me.

I found nothing about this model in the Web-sphere.

Answer 1

Hello, I worked a lot of time with industrial automation and I can give you a north. Communication with Plcs can be done using various means, one of them is with OPC protocol ( OLE for Process Control ), most Plcs ( Siemens, Rockwell etc) have this protocol, but there are other interfaces like RS232. The OPC is a protocol that facilitates data capture, usually the manufacturer provides a "server controller' that interface between your application and the hardware. In the Rockwell Plcs of the Contrologix family, who does this interface is Rslinx, for Plcs Siemens there is STEP 7. In this "server controller" you map all the PLC addresses of your network to add which bits of each PLC you want to "share". After this configuration, you must have a component for your programming language, in my case I used Delphi with the paid component Kassl OPC Client, but there is also the version for .NET. In these components you configure the PLC addresses and the bits you want to capture.

The PLC may store some information, but it is limited because the hardware has little storage capacity, and is programmed to perform a task. Then it provides you the information in real time, just you capture this information and structure in your SQL database and generate history if applicable. There is a very interesting free software project, the Scadabr. This software has all the necessary components for you to already start developing your monitoring system with Plcs.

There is not much information about industrial automation even on the internet, it is a very restricted market, but it was worse in the past.