write to plc using ni opc

[bikarna.pokharel@student.hamk.fi]

Hello! I have connected Simatic CPU-315-2DP with an MPI driver to LabVIEW using NI OPC Server. Now, I can see the change of state ( for example Boolean 1 to 0 and vice versa) but I have not been able to write to the Simatic CPU form LabVIEW (for example using a toggle switch). While creating the tags in the NI OPC, I had also defined the tags to Read/Write. Please help me, if possible with a video or a document with screenshots. Thanking in anticipation.

[Finland_]

Hi Bikarna!

Thank you for contacting NI Technical support. Since I don't have you in our database, I will try to help you out via the forum. First, I need to know more if you have driver for LabVIEW or not? If you do then it should be easier. Using NI OPC you could always see the changes but I am not sure if the device have the feature to make changes using OPC or not. This is a feature that you must check with the manufacturer. However there are variety ways to connect LabVIEW to any PLC with Modbus. Please check the link following: http://www.ni.com/white-paper/13911/en

I hope that it might be helpful for you. I will contact with you via email later on today. Have a nice pääsiäinen as we call Easter in Finland.

BR,

Make Nguyen

National Instruments Finland Technical Support

[bikarna.pokharel@student.hamk.fi]

Thank you for the reply! Actually I want to connect the PLC using OPC, so I did not think about other ways. What kind of driver should I have? I am not so advanced user so if you could explain what kind of driver you are talking about. Yes maybe the PLC might not have feature to get command from other applications. As I have connected the PLC using the S7 MPI driver, and while creating the new channel in OPC I have used S7 MPI driver. Thus, I suppose the MPI is also the driver for labview to PLC. 

[Finland_]

Hi Bikarna!

Have you seen the white-paper I sent you as a link? LabVIEW itself is OPC server. If you want to connect PLC using OPC please take a look at the white-paper as following:

- Connect LabVIEW to Any PLC Using OPC: http://www.ni.com/white-paper/7450/en

BR,

Make Nguyen