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InTouch Item Name Suffix
Odd 'F' suffix in existing InTouch project Tagnames' items don't work well with FSGateway.

I'm working on an existing Wonderware InTouch project. For now, InTouch communicates with a DDE Server (PCDDE) wich is connected to 4 S7-400 PLCs over Ethernet.

I would like to replace the DDE Server with an OPC Server + FSGateway. I already have tested the setup on a spare computer and PLC and everything works fine.

My problem is with some of the Tagnames' Item Name in InTouch. For some reason, the I/OReal Item names are appended with a "F" suffix.
I've search for an explanation about this suffix but I can't find anything.

With the suffix the communication with the PLC works fine trough the PCDDE server but it won't trough the OPC server. If I remove the suffix everything works well.

Can you tell me what is that suffix for ? And if there is a way to make this work without removing the suffix from all the tags..

Thank you in advance.


By Fred Loveless on 1 April, 2009 - 6:28 pm

Gilles, I am digging way back into my memory for this but I do believe that the suffix was used to denote the data type. In this instance the data type would be Float.

Fred Loveless
Kepware Technologies

If you have to modifiy a batch of item addresses in Intouch tagnames, try to use DBDump function (accessible by Intouch application manager), then you can open the .CSV file in Excel and modify your tags using search and replace and many other excel features. Keep only tags you need to change and save as .CSV. You will find Wonderware documentation concerning DBDump / DBLoad.

Be sure to backup your application before you attemps a DBLoad. Load errors (if occurs) will be documented in Wonderware Logger.

Good luck.

Thank you for your answers.

I've already used DBDump/DBLoad for other tasks and it's quite usefull when you have a lot of tagnames to create or modify.

Fred, the suffix is in fact appended to items that point to float values in the DB.

I've now found that if I remove it, InTouch can no longer display the value correctly. It writes 32767 (wich is "Max Raw" or "Max EU" setting in the tagname details) or -32768 if the float value is negative.

I previously thought that it was working without the suffix because I was writing and reading FROM InTouch. Now that I've written in the DB from the SIMATIC software, I can't read it correctly in InTouch. So I also tried it on the site with some float values from flowmeters and it doesn't work either (32767 is displayed).

I hope I've explained myself well.

Best regards,


Not sure about your OPC server syntax, but the old method of using OPC servers with InTouch was to use a program called OPCLink. This required tagnames to be prefixed with "f","d","m" or "i" to denote the type of tag (float,discrete, message etc).

FSGateway replaced OPClink but you are still able to map "old" style tag names to the actual OPC tag using the configuration screens in FSGateway/Sys Admin.

I personally always tick the use tagname as I/O name in InTouch and do the mapping in FSGateway. This allows you to change tag addresses while running IT viewer.

Suggest your look in the PCDDE pdf manual.

For my GE Fanuc DDE server, " F" suffix is used for IEEE floats as previously mentioned. There is also " S" for signed integers, etc.