Connecting a Siemens S7-300 PLC to NI OPC Server

[DanJack]

As a part of the final year Bachelor Thesis project I and two others are involved with, I have been tasked with setting up an HMI/SCADA system to control level and flow in several water storage tanks. This is to be done locally via a "Operator Panel" and also remotely over the Internet via webbrowser. These storage tanks and control system is placed on a wheeled demonstration model so it can be used in classrooms and auditoriums. As such, I have a Siemens S7-300 PLC and the latest edition of LabVIEW (2009 Professional Ed.) available to me. In order to create a HMI system, we will also acquire the NI DSC module as it should have everything we need (NI OCP is included?).

Since this is a bachelor project and the school is basically paying for everything, we are on a rather strict budget. This means that we currently haven't settled on a solution for the "Operator Panel" since this would be dependent on how the PLC and panel interfaces. What we would like to do for simplicity sake is to use commercial laptop computer with touchscreen capability thus having a low cost "all-in-one" solution, both for local input & control and web publishing capability. Now, most computers today doesn't have serial comports anymore, but rather USB ports.

On the OPC server webpage under the OPC Device Connectivity heading, it is specifically stated "Siemens HMI Adapter for S7-300/400 via Serial with HMI adapter". I assume this refers to the following Siemens product: https://support.automation.siemens.com/WW/llisapi.dll/csfetch/8774263/hmi_adapter_x.pdf?func=cslib.c... (6ES7 972-0CA1X-0XA0).

Does this mean that the OCP server can only use a Serial connection via the HMI adapter for the S7-300 directly? Would it be possible to use a driverless Serial to USB adapter with the HMI adapter, or for example the Siemens CP5711 MPI to USB adapter? If it is not possible to use a USB based solution, We would have to use an older desktop PC with an serial comport or an additional PCI card and that is something we would like to avoid.

Any help on this matter would be highly appreciated.

-- DanJack, NUC Norway

[DanJack · Accepted solution]

Through 3rd-party vendors I've found out that the NI OPC server drivers for Siemens S7-300 ONLY supports legacy RS232 communication, no USB connectivity of any kind. You can only either use the MPI to RS232 adapter or the HMI to RS232 adapter.

-- DanJack, NUC Norway

[CarlosOtiniano]

now this is a problem the PLC S7300 does not support some functions of communication when you want to make a simulation may not be accessible from OPC Server, this by PROFIBUS Siemens USB / MPI + PLC S7300/400 protocol adapter cord