Connecting a Siemens S7-300 PLC to NI OPC Server

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 storagetanks and control system is placed on a wheeled demonstration model so that 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 OPC is included?.

Since this is a bachelor project provided by the school 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's sake is to use a 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: HMI-adapter (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

Problem solved

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

I would seriously consider to purchase some newer hardware. The serial MPI or HMI adpaters are painfully slow. And the need to be within a few meters of the PLC will be a pain.
Why use the NI OPC server, if it is limited to serial ?

I suggest www.deltalogic.de. They have an ethernet-to-MPI/DP adapter and a matching OPC server.

This one is similar: http://www.ibhsoftec-sps.de/german/IBH_Link_S7_Plus_Plus.htm

I am guessing you can get the OPC server from the vendor free of charge, since you are an educational institution.
You may have to pay for the hardware, but I think that you can get the software for free.

Ethernet option

JesperMP said:

I would seriously consider to purchase some newer hardware. The serial MPI or HMI adpaters are painfully slow. And the need to be within a few meters of the PLC will be a pain.
Why use the NI OPC server, if it is limited to serial ?

I suggest www.deltalogic.de. They have an ethernet-to-MPI/DP adapter and a matching OPC server.

This one is similar: http://www.ibhsoftec-sps.de/german/IBH_Link_S7_Plus_Plus.htm

I am guessing you can get the OPC server from the vendor free of charge, since you are an educational institution.
You may have to pay for the hardware, but I think that you can get the software for free.

Click to expand...

The reason for using the NI OPC server is mostly due to LabVEIW, since that is what we have been requested to use as HMI. As I understand the OPC concept, device drivers and the client program are independent of each other? Both drivers and client are a industry standard and as such almost any driver should be compatible with any client?.

The NI OPC server does apparently come with support for TCP/IP Ethernet communication with the standard Siemens 200/300/400 series PLCs. If I then choose to go with the ACCON-NetLink-PRO cable from Deltalogic there shouldn't be any special connectivity problems per standard?

PS. Would such a setup work via a router? So that you could have the PLC and Internet accsess simultaneously?

-- DanJack, NUC Norway

DanJack said:

As I understand the OPC concept, device drivers and the client program are independent of each other? Both drivers and client are a industry standard and as such almost any driver should be compatible with any client?.

Click to expand...

Exactly, so there is no absolute requirement to use the NI OPC server if Labview is an OPC client.

DanJack said:

The NI OPC server does apparently come with support for TCP/IP Ethernet communication with the standard Siemens 200/300/400 series PLCs. If I then choose to go with the ACCON-NetLink-PRO cable from Deltalogic there shouldn't be any special connectivity problems per standard?

Click to expand...

I think, but am not sure. There is some trickery about having to specify "rack/slot" in a special way to identify the MPI adress.
I would ask Deltalogic. And at the same time ask them if you can have their OPC server for free, given your status as an educational institution. Using the native OPC Server from Deltalogic will probably be most straightforward.

DanJack said:

PS. Would such a setup work via a router? So that you could have the PLC and Internet accsess simultaneously?

Click to expand...

Maybe. It is possible with most ethernet configurations that I know, but I would ask Deltalogic to be sure.