Project corruption kills EtherCAT Digital I/O

[viSci]

In both LV2009 and LV 8.6.1 I have experienced a type of invisible project corruption that results in damage to etherCAT scan engine access to Digital Output resources.

Image a working cRIO 9074 with a 9144 expansion chassis that has been working perfectly for an extended period of time. A change is made to source code, compiled and

deployed to the target. Something goes wrong with the deployment and both the project explorer and the cRIO crash hard. The cRIO has to be manually rebooted and LV on the development machine has to be terminated and restarted. After restarting and redeploying again, everything is working fine except that Digital Outputs are not generating a voltage change on the cRIO 9076 module that resides in the 9144 expansion chassis. In the Distributed System Manager, digital outputs on the 9076 are forced but no electrical signal change is observed.

All other modules are working normally. cRIO is then reformated and project is redeployed but the problem persists. Swap out a new 9144 and 9076 module, still the problem persists.

Open a new project and add cRIO target and finally the outputs start working again. Open the original project, remove the cRIO target, add cRIO target, redeploy and then all is well.

What is the lesson learned?

Apparently, there was nothing wrong with the hardware or the source code or configuration within the project yet something 'invisible' had become corrupted in the project.

The problem is that there is no way to validate the project to see if something has gone wrong internally. Also no errors were generated.

Has anyone experienced anything like this?