direct referencing tags for factorytalk me

I'm new to the PLC world. So, take it easy on me.

Where I work we are siemens heavy and only have a few mech. AB.
Here is my problem I want to add a button to the HMI. The PLC is a Logix5562 and the factorytalk is ME version 7.0. Reading on here it looks like direct referencing tags would be my best way to go but need some more info on how direct referencing tags work and the path on how to get them from the PLC. This is an older system and someone at one time added a button so I'm just trying to copy what they have done. I have added the tags on the PLC side I just need to know the best way to get them to factorytalk. This is what there tags looks like on the other button. I have changed the names. Does the brackets at the end mean direct referencing tags?

{::[Test_example]ReRunSelected}

when you create a button or object you just point it to the tag in your plc if you are online or you can point to the offline code on your pc

The part in square brackets is the shortcut to the PLC. In your communications setup, you define the type of PLC and it's IP address (or other network address or path), and save it as a shortcut called, in your case, "Test_example".

The path that the HMI data has to take to get to the PLC might be very simple (direct ethernet connection) or very complex (multiple "hops" across various networks and devices); it doesn't matter. The shortcut is set up once to tell the HMI "when I say PLC1 I want you to connect to this PLC." Then all you do is tell it which tag in that PLC you're interested in.

So in your case, your HMI will go looking for (or writing to) the tag "ReRunSelected" in whichever PLC is configured as the target of the "Test_example" shortcut in your communications setup. Simple, right?

The curly brackets are just to signify that everything inside is one tag address, so that if you're using it in some kind of expression, the expression knows to evaluate the whole string as one value, instead of evaluating parts of it in connection with previous or subsequent statements or operands.

The double colon I'm not 100% sure about, but I don't believe it is required when using tag-based PLC's. My understanding is that you need it when talking to older, register-based PLC's like the Micrologix or SLC range. These PLC's use an address like "N7:0" or "B3:0/1", and if I recall correctly, putting "::" at the start of the address just tells the system that the following address has colons in it and they must be evaluated as part of the address, not viewed as another logic operation or similar. As I said, not 100% certain that I'm completely correct on that one, but I'm sure someone will be along in a moment to tidy up anything I've gotten wrong

When you open the Properties for the button and go to the Connection tab don't type a tag name. There are too many ways to get it wrong. There is a little button to the right of the value field. Click on that and you can browse to your PLC and see the actual tags in the controller.

There is a Refresh All Folders option that might be necessary for it to see the new tag. You can right-click on any item in the left hand window and you should see an option to Refresh All.

Here is a video on YouTube that walks you through browsing for tags.

https://www.youtube.com/watch?v=19ue0Ra3ZN0

OG