OPC tags fom Siemens S7

Hi
I'm just learning about OPC now and have never worked with PLCs either. I need to read values from a Siemens PLC. The PLC receives current inputs as 1 of its many inputs. Using Labview, and I able to connect to the PLC and set up OPC tags so I can read in the values or will have to alter the PLC program to set up tags to send the data?
Thanks

Hello JChec,
I am not an expert on that particular PLC and I do not know what code you already have running on it, however, you are correct in needing to setup an OPC Server. You cannot directly connect to your PLC from LabVIEW. LabVIEW connects to that OPC Server to read its tags. As opposed to free OPC Servers that you may be able to find, a suggestion is to use the NI OPC Server; while not free, it is fairly straightforward to set up via a nice GUI and gets you access to excellent technical support.
There is some information at the following links that I think may be of assistance:
NI OPC Servers
   http://sine.ni.com/nips/cds/view/p/lang/en/nid/4584
Supported Device & Driver Plug-in List for NI-OPC Server
   http://zone.ni.com/devzone/cda/tut/p/id/6417#toc34
Depending on the scope of your project, an additional module that you may be interested in is the LabVIEW Datalogging and Supervisory Control (DSC) Module. This increases the functionality of LabVIEW and your OPC setup as described by its homepage.
LabVIEW Datalogging and Supervisory Control Module Homepage
   http://sine.ni.com/nips/cds/view/p/lang/en/nid/1010
Regards,
Charlie Piazza
Staff Product Support Engineer, RF
National Instruments

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Attachments:
manual_writing_to_plc.png ‏298 KB

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Attachments:
Get Tag List.vi ‏38 KB

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locate_fflv_in_labview82.jpg ‏214 KB
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OPC tags fom Siemens S7

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