I am having some strange behavior on an ACE project that uses PIACEPoint.NextEvent. My code is set on a one-minute clock schedule. It is designed to run calculations one time per shift, as soon as certain Input values are written to the archive from a manually run shift production report. On any given shift, before those input values appear, as well as all the scans after the scan that writes the calcs, the code sets all output tag .SendDataToPI parameters to FALSE then exits.
The issue is this: The module runs successfully (properly calculates and writes data with a start-of-shift timestamp) when it finds a value using .NextEvent but then for the next 30 scans (30 minutes, once per minute), it writes "Calc Failed" with the current timestamp, and the Message Log shows the error message "Object reference not set to an instance of an object". Then the "Calc Failed" ceases and no more Object reference errors in the Message Log. At the start of the next shift, when a new value comes in the from the shift production report, this cycle starts all over again - one good value and then 30 "Calc Failed"s.
Both the ACE server and my development station are using ACE 2010 R2 SP1.
This behavior sounds very similar to the "Fixed" Punch List Item 24159OSI8 on Page 2 of the Release Notes. Is it possible that there is another way to cause this error?