Expression Issue and tag placeholders

[Fred R]

I am trying to compare two values that are tag place holders like this #3 == #10 for a visibility expression.

In my parameter file #3 is a direct- reference to a tag in the PLC that is a decimal, #10 is a value 3713.

When I try to run it in FactoryTalk, I get an error ‘Failed to resolve item's ID '3713' because it does not exist on any server’ to me it looks like it is trying to use it as a name and not its value.


Is there a way to force the expression to make #10 a numeric value instead?​

 

[Ken Roach]

Welcome to the Forum !

You're correct that Placeholders are looking for Tag References.

I think the easiest workaround for this is to create an HMI Tag that contains the constant value you want to use, and reference that.

In the past, I've just given these names like "Constant_4096" and put them in their own folder.

 

[Fred R]

Thanks

Just did not know if I could pull the real value out. Thanks for you help.

 

[RSL]

As usual Ken speaks the truth. I have struggled with this and there is no work around that I have found so far other than Ken's suggestion.

I as a matter of practice usually have HMI tags called "1", "2","3" etc. I always have 0-9 and have had them much higher. I make them memory tags and place them in the root folder. This allows me to use them in expressions as needed anywhere in my application. I prefer not to put them in a folder or prefix them.

RSL