Execute a VI only once on an event becoming true the first time

[ControlAutomation]

I am using CompacDAQ hardware for a press monitoring application.  I have an absolute multi-turn encoder wired to a 9435 and I want to trigger a measurement and storage VI once whenever the encoder is greater than a certain angle (e.g. 270 degrees).  The trouble is, I cannot seem to make the result of a boolean comparision only execute one (like a rising edge).  This is known as one-shot functionality in the PLC world.  How can I implement this in the Labview environment?

Thanks,

Mike Voll

[Christian_L]

Look into using Shift Registers on your loop and using the Greater Than comparison on your Boolean condition to trigger your operation.

Message Edited by Christian L on 05-15-2009 09:48 AM