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J
JaimePR10-Marble
10-Marble
May 30, 2025
Solved

Advanced Tags: Nested condition formula allowed?

  • May 30, 2025
  • 1 reply
  • 912 views

Hello community,
I would like to know if it's possible to create a nested condition formula using a Derived Tag in Advanced Tags in KEPServerEX. Something "Condition ? Value_if_True : Value_if_False"


The idea is to retrieve certain tag based on a tag value, for example:

plc1secuence == 1 ? plc2tag1 : plc1secuence == 2 ? plc3tag1 : -1

 


Tried using IIF statement as well but it doesn't like it either...

 

Looking forward to hear from you.


Cheers,

Best answer by pshashipreetham

Hi, 

 

Yes, nested conditional expressions are supported in KEPServerEX Advanced Tags using the ternary operator. Your syntax just needs proper grouping using parentheses. Here's a corrected version of your logic:

 

plc1sequence == 1 ? plc2tag1 : (plc1sequence == 2 ? plc3tag1 : -1)

 

This ensures that the second condition is only evaluated when the first one is false. Avoid using IIF—it's not valid in this context. Stick with the condition ? true_value : false_value format and use parentheses to control the logic flow.

 

Thanks,

1 reply

P
18-Opal
pshashipreetham18-OpalAnswer
18-Opal
June 2, 2025

Hi, 

 

Yes, nested conditional expressions are supported in KEPServerEX Advanced Tags using the ternary operator. Your syntax just needs proper grouping using parentheses. Here's a corrected version of your logic:

 

plc1sequence == 1 ? plc2tag1 : (plc1sequence == 2 ? plc3tag1 : -1)

 

This ensures that the second condition is only evaluated when the first one is false. Avoid using IIF—it's not valid in this context. Stick with the condition ? true_value : false_value format and use parentheses to control the logic flow.

 

Thanks,

J
JaimePR10-MarbleAuthor
10-Marble
June 2, 2025

Hello Shashi,
Thank you for your reply. I had tried your suggestion before but it does not like the "ternary operator expression".
Downloaded the latest version just in case this was added in newer versions but nothing (same syntax error as usual).

Tried the following dummy examples:

TAG(Channel1.Device1.TestSecuencia) == 1 ? TAG(Channel1.Device1.Test1Unidad) : TAG(Channel1.Device1.Test2Unidad)
(TAG(Channel1.Device1.TestSecuencia) == 1) ? TAG(Channel1.Device1.Test1Unidad) : TAG(Channel1.Device1.Test2Unidad)

 

The nested one (the one you described in your post - using grouping parentheses):

TAG(Channel1.Device1.TestSecuencia) == 1 ? TAG(Channel1.Device1.Test1Unidad) : (TAG(Channel1.Device1.TestSecuencia) == 2 ? TAG(Channel1.Device1.Test2Unidad) : -1)

 

All previous examples throw: "Expression invalid: Syntax error: '?'"

inline expression error.png

Currently using KEPServerEX 6.17, V6.17.269.0 (customer running older: V6.9.572.0)

    M
    MKhatri15-Moonstone
    15-Moonstone
    August 6, 2025

    Greetings!

     

    If you are still experiencing the issue, I kindly request you to open a support ticket with us for further assistance.

     

    Please log in to mykepware.com and submit a support ticket. Our team will be happy to assist you with the resolution.

     

    Thank you for your cooperation.

    Regards,
    Mohit

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