Recursive s+h condition


I want to set an IObox only if the difference between
a source value and destination become a specific amount.

So I thought I might take a S+H node send the value
to my IoBox and connect the = condition beteween my
bottom IoBox and the source of the S+H node.
Obviously a recursion is not allowed here this way.

How can I ‘workaround’ this?

The reason why I want to do this is to clean a signal
from RS232 which jumps up and down in it’s value. So
the patch should only react if there is a change of let’s
say 3 units.

Thanks for any help!

framedelay (Animation) does the trick.