How to avoid Same PLC adress with another multiple tag Name??
There must be some indication while creating the tag with Same PLC adress and Multiple names??
Or should be pop up that "the adress is already present, want to continue "??
Please Suggest…
You’ll have to script something that uses system.tag.browse*() and sorts the results by OPC Item Path. A built-in warning would have to be a feature request.
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Thank you for your reply…But I am thinking that Ignition should develop such utility…
I’m curious if you are aware of another HMI that provides this feature. To the best of my knowledge I have not seen that in FactoryTalk or Wonderware and I’m pretty sure I haven’t seen that in iFix, but it’s been a while.
Such tags are certainly a nuisance when upgrading older systems, but they are hardly detrimental to the system itself, after all it’s going to read that address from the PLC in a block read and assign it to the various tags. Occasionally I’ve seen instances where an individual would deliberately bring in the tag twice and perform different actions on the tags.
Regardless, you have my interest piqued, what is your reasoning on why duplicate names for the same address is such a serious issue that your should get a warning message?
Hi abhishur,
These serious issue because if you are working on the some back up from client side and you don’t know is the tags of that particular address are made or not?? and you made these tags even they are present in the system and which increase the load on the communication…These observed when you have Tag count around 20K to 25K
Well I don’t know the inner most details of how the Ignition driver works, but I do know that typically with other drivers tags will be read in blocks. This means that the driver has to scan through the tags ahead of time to see what addresses you will be reading from (or at worse create the list during the first read through of the tags). So if I have two tags with vastly different names they will still be grouped together and should only require one read from that address rather than two.
However, if that is not the way Ignition handles things, you’d have to have an insane amount of duplicate tags, even in a 25K tag system for it to have any depreciable affect on your communications. If you’re having communication delay problem I would say the more likely issue is all the tags being in the same scan class. If a PLC is offline, or a tag is trying to read from an address that doesn’t exist, then the entire scan class is held up each scan waiting for that tag to time out. By splitting tags into scan classes based on the PLC being read from you can ensure that the loss of a PLC doesn’t slow down you’re entire network.
Prevention of duplicate tag addresses is such a low impact to the system issue that it really makes sense for it to be the responsibility of the integrator to not create a bunch of duplicate addresses, at least that’s my 2 cents. However, you can place all ideas like this over at
http://ideas.inductiveautomation.com/forums/255378-ignition-features-and-ideas
if enough people agree with you, they’ll make adding that feature to a future release a priority. 