C4C Workflow rules check if value is empty

I have a problem with checking a value in the workflow conditions.
I have to check on a date field if its not empfty. If thats true the workflow should be triggerd on save.

But this does not work properly.
Can someone help me on how to check if a date /value should be not empty? (in Workflow step 'define conditions'.

Thank you

BR Timo