Ignition/OPC tag write is overwritten, Logix, FBD

[jds8086]

Hardware: 5069-L320ERMS2
Software: Logix Designer 35.11 / Ignition 8.1


Issue: When attempting to write to the tag "HMI_DRV200_DynamicTrim" in ignitition, the tag write returns "GOOD" but the value does not change. If i disconnect the OUT of the following AOI from the tag, the value will change when writing from ignition. To my confusion, disabling the routine (not calling it with JSR), will not allow the value to update via ignition. I assume i need to go about this differently and that there is no actual software issue, but I'm not sure exactly why the value does not change when writing.

*EDIT* I've found that i can't ever change the value of the tag in Logix Designer itself unless i disconnect this tag from the AOI's OUT

 

[robertmee]

The AOI output is a destructive instance of the tag. It will always overwrite any value you set from ignition.

 

[jds8086]

The AOI output is a destructive instance of the tag. It will always overwrite any value you set from ignition.

That makes sense, but if that is the issue, then i am confused as to why if the routine containing this instruction is not being called, why is it still modifying the value? Also, why does setting the EnableIn bit of the AOI to false not keep it from writing to the tag?

 

[Cheeseface]

FBD instructions are always enabled. Those bits are for ladder.

although you seem to have a custom AOI, so who knows what it does with the bit

 

[JeremyAdair87]

Right click the AOI and view its logic.

You have something writing to that tag in more than one location.

 

[jds8086]

Right click the AOI and view its logic.

You have something writing to that tag in more than one location.

Here is the cross reference for the tag in question. I'm not sure why it is calling the OREF destructive when that appears to be the only place it is modified from. Just for s&g, at the very last rung of the program i added some logic that would just add x amount to the value of the tag when a test bit was set, even this would not change the value of the tag (which i would have assumed if it was an issue of the tag being overwritten elsewhere, this should have "won").