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Reading whichever PLC Address changin TAG properties dynamically.

Created by: thidalgo at: 9/27/2006 1:29 PM (10 Replies)

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9/27/2006 1:29 PM	Rate (0)
thidalgo Posts: 68 Rating: (0)	Hi to everybody I want create a screen to manipulate the value of any phisycal address into the PLC. It's posible to link a control with a TAG and change dynamically the physical address or datatype of this TAG, in order to view the memory address that we type for example in a text box ? Thanks a lot.
thidalgo Posts: 68 Rating: (0)
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9/27/2006 3:34 PM	Rate (0)
Nemo Posts: 3149 Rating: (171)	Hi you find a good description in WinCC online help, just search for "createtag" [:D] nemo
Nemo Posts: 3149 Rating: (171)
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9/27/2006 3:43 PM	Rate (0)
thidalgo Posts: 68 Rating: (0)	Hi Nemo, Sorry about my ignoarance, but, ... I've followed the steps you indicate without success. Nothing appears setting "createtag"in the search box intothe online help section. Anyway, I'll try to find information in the WinCC help files. Thanks.
thidalgo Posts: 68 Rating: (0)
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9/27/2006 9:45 PM	Rate (0)
Nemo Posts: 3149 Rating: (171)	Hi, did you search on the register "index" or "search"? If you don´t find it this way perhaps looking for "vba" could help. If you don´t get along leave a note here and I will have another try. nemo
Nemo Posts: 3149 Rating: (171)
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9/28/2006 4:42 AM	Rate (0)
Dec Gold Expert Joined: 5/19/2006 Last visit: 10/7/2024 Posts: 549 Rating: (107)	Hi thidalgo, Are you looking for some sort of indirect addressing ? Dec

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9/28/2006 6:02 AM	Rate (0)
Danielle Posts: 1275 Rating: (123)	Hey there! Are you trying to create tags dynamically? Or at least change the tag type and address dynamically?
Danielle Posts: 1275 Rating: (123)
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9/28/2006 1:40 PM	Rate (1)
Reuben Posts: 70 Rating: (13)	Hi You can programmatically add tags during runtime, but I don't think you can always delete or modify them. The ODK for "GAPIDeleteVariable" states "This function should only used when no project is active". There does not seem to be a function to modify an existing tag. Probably the easiest thing to do is to use (assuming Siemens PLC) a function in the PLC to perform indirect addressing based on input from WinCC. So you would have maybe three tags to define the address (DB No, BYTE address, datatype) and then two other tags for reading / writing the addressed value. *WinCC Tag Debugger* Here you can download a simple program I wrote to easily select any tag in the active project and view or edit the value in various formats (bin, dec, oct, hex, bits). Unfortunately, the tag must actually exist in WinCC so it may not help you: http://www.allottware.co.za/RAWeb.dll/Page?n=downloads_tagdebug *SIMATIC NET OPC Test Client* If you use the SIMATIC NET OPC server for your Siemens PLC, there are also many freely available OPC client tools to use and you can address anything in the PLC (google), but it is probably easier tosimply use Step7. Here is an app I wrote to test the SIMATIC NET OPC Server (the nice thing with SIMATIC NET OPC client is that it can automatically handle for you datatypes like S7 DATE_AND_TIME that are not natively handled by WinCC): http://www.allottware.co.za/raweb.dll/Page?n=downloads_opctestclient
Reuben Posts: 70 Rating: (13)
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9/30/2006 9:53 AM	Rate (1)
Mehrnoosh Posts: 102 Rating: (9)	Hi Actually you can’t delete a tag or change its name in runtime. But if you want to make a user interface for operator to make him/her enable to change the address of a tag, you can make an interface to the variable table in WinCC table “MCPTVARIABLEDESC” column “addressparameter” in configuration database in graphic disigner. But I myself don’t suggest doing this, it is better to don’t let the operator change the tags configuration. And I don’t suggest changing WinCC tables directly. But if you have to do this be careful. Best regards, Mehrnoosh
Mehrnoosh Posts: 102 Rating: (9)
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10/3/2006 10:21 AM	Rate (0)
Reuben Posts: 70 Rating: (13)	Hi I was fiddling with those things again after reading Dec's quiz challenge. What I found is that if you simply edit the SQL definition there is no guarantee that WinCC is going to refresh the internal definition for the tag. If you use the CS api or VBAmethods then it can work, although the documentation says not to do that in runtime! Also, I managed to kill the script engine a few times when fiddling with the SQL database, so again, this method only recommended for cowboys...not someone developing operator control for a nuclear powerplant [:D]...
Reuben Posts: 70 Rating: (13)
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10/3/2006 12:27 PM	Rate (0)
Mehrnoosh Posts: 102 Rating: (9)	Hi Reuben You mean to change the MCPTVARIABLEDESC value using a script?
Mehrnoosh Posts: 102 Rating: (9)
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