Bring in Web Data to Control / OPC

I'm sure one of you guys done this before. What's the most straight forward way of bring in a number from a web page off the internet and use it in a control environment?

This is not the exact thing I want to do, but just as an example; say, bring in the current outside temperature on a weather website and use it as a provess variable. I did a bit of search and was surprised there doesn't seem to be a ready made software available.

I mess around myself and am able to do a web query using MS Excel and put the number in a cell and that's as far as I got today. If I can automate that process and expose the number in the cell to an OPC server then I'll be almost there but any suggestion are welcome.

Not sure how to do it via opc but we do it with the 1756-EWEB module. I know of a place that also has thier live stock price on all their HMI systems.

You could use a eweb to logix and then read it from the clogix via opc the spit it out where you need.

So how you do it via EWEB? Looks like it just display PLC data via web server or does it also shoot data the other way (to PLC?). I don't need the OPC if I can output to PLC's analog output.

We did this several years ago using Excel and wonderware intouch.Excel will pull the data off a web site and a tag in wonderware was pointed to the cell. There have been a few bugs over the years with new versions of excel and when your web page updates, or the developer changes position on the web site. We used to automatically reboot the P.C. at midnight then restart all the necessary programs in order.

Oh, ok, so WW will retrive a cell off Excel? Do you remember the detail of how that's done?

I'm not at the plant today, so i'll have to rely on memory.
In WW make an access node pointing to the Excel file you are using to get the data from the web. create a tag as an i/o interger and use the Excel access name. addressing protocall is something like R6,C10 ( row 6, colum 10) to point to your cell. The WW help files have it in there for the addressing.
Hope this helps.

We do this, Our web guys dump the necessary information into SQL.

I use Ignition when i need the values in the PLC(outside temp) and just a bog standard SQL query from the SCADAs otherwise.(iFix, Wonderware, RsView).

harryting said:

So how you do it via EWEB? Looks like it just display PLC data via web server or does it also shoot data the other way (to PLC?). I don't need the OPC if I can output to PLC's analog output.

Click to expand...

The EWEB is Bi Directional. We do writes in XML from a external Program.

We also do this using a T Manager from oldi http://www.oldi.com/tManager_home.shtml which will read data from a SQl or Oracle DB we use both and put that data in the specified tag. This also is Bi directional.