FactoryTalk View SE Dynamic Object

[Wheeels63]

Hello everyone,

Is there an expression that can check to see if the tag exists before evaluating or another way of dynamically forcing specific errors to be ignored and make invisible?

Shoot me any questions you have and thanks.

 

[RonJohn]

Welcome to the forum. It reads as though you have a specific situation in mind but I'm not quite following you. More detail from you could be helpful.

Are you talking about checking for tag existence when developing an object in FTV Studio?
If you're talking runtime, I'm not sure how a tag could pop in & out of existence in a PLC if it's referenced by FTV.

 

[jkerekes]

Use the comm_err(tagname) function in the expression.

 

[Wheeels63]

Trying to create a global object that will use parameters/parameter files. The object will be for a transmitter that has different settings for alarms. HH, H on some, L & H on others. Wanting to have an expression that will ignore the HH if it doesn't exist for the transmitter.

I can create a global object where I manually input each alarm and just put a value of 0 if it doesn't exist, but just trying to think of a cleaner way if possible.

Reference
1 - Existing RSView 32 being upgraded to FactoryTalk View SE and needing to keep the structure of having HMI tags and not utilizing direct reference tagging sadly.
2 - Programming changes for the controllers will be minimal.