Need Help With Deciphering Panelview Tag!

[JaguarXFR]

I currently have an issue trying to track down a tag in the PLC. This tag is for a panelview indicator that was custom created. Can someone assist with deciphering how this tag is written?

Tag in HMI: {::#1Program:SafetyProgram.#2.Door[#4].HMI_Open}

I was able to find the HMI_Open tag inside of a custom built AOI.

 

[Ken Roach]

An aside: AOIs and UDTs are seldom the best way to interface your HMI with your PLC. The HMI has to read the entire complex datatype and extract the necessary data, which can impact performance, and you will find yourself cursing and complaining unnecessarily about things that are meant to be pre-defined and fixed at design time being difficult to modify and edit during runtime.

That being said: welcome to the PLCTalk forum community !

{::#1Program:SafetyProgram.#2.Door[#4].HMI_Open}

The presence of the #1, #2, and #4 placeholders mean that this object relies on a "Parameter File" to deliver those components of the tag.

#1 is surely the Shortcut name. #2 is probably the AOI instance tagname. #4 is the Door sub-element inside the AOI.

Look for a Parameter File that is invoked when the Display that contains the object with this direct tag reference is opened.

 

[JaguarXFR]

Ken,

I appreciate the help! I would not have programmed it this way either. Unfortunately it hit the production floor this way from the OEM. The parameter file was being referenced by a hidden box underneath a pushbutton... I completely overlooked it!

 

[kamenges]

Originally posted by Ken Roach:

The HMI has to read the entire complex datatype and extract the necessary data...

Presumably the "read the entire complex datatype" thing only applies to reads and is handled differently for writes. If not I would expect to have seen all sorts of wonky machine operation over the last 15 years or so that I have not seen.
Said another way, if the HMI can only operate on the base UDT tag as a whole then the only way I can think of to handle a single element write is to read the whole UDT tag, insert the data into the read copy then write the whole thing back to the plc. The danger is some other function may have changed something in the UDT tag in the meantime so the transfer would require a semaphore to prevent data access to that tag until the new written version of the UDT tag is back in place.

Keith