I need to know how to establish communication between between a Visual Basic 5 Enterprise Edition and a Simatic S5 PLC. How do I get the data from the PLC?
If you are using a windows based SCADA which is already communicating with the PLC then you can try using the Dynamic Data Exchange {DDE} facility which is normally available in all SCADA packages , to get the required data in your VB program .
1. Buy a OPC-Server for Windows and use direct connection via AS511/RK512 via COM-Port and an RS232<>TTY coupler 2. Buy a OPC-Server and use H1-Bus (Ethernet) or Profibus-FMS to get more speed in communication. But you need on the PLC-side the right CP (Comm-Processor) and in the PC the right PCI-Card. (Ask Siemens for the parts) 3. Cheap solution: use serial-connection (as in 1.) but no OPC-Server, use a driver that you can link into your basic programm (Prodave by Siemens, or S5-Link by Process-Informatik, there are some others) 4. We use for the serial-machine a communication-server (part of T.I.R.S.32 visualisation, they have no runtime-fee) connected via Profibus-FMS. And have our special application written in VB5 and VB6, communicating throu the communication-server software, which is a client-server software.
You can do it using an OPC Server and an OPC Client. The OPC Server is used to read/white data from/to PLC, but you will make an OPC Client in VB to read/white data from/to the OPC Server. Go to www.opcfoundation.org for more information about this. Best Regards
Armando Abraham
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