Troubleshooting EMSA Data Spikes on the Same cRIO

Issue Details

In the EMSA system, data dropouts are observed on some assets when using the same cRIO. The issue presents as signal spikes or missing data. This behavior may only affect specific assets or channels connected to the same hardware.

Solution

This behavior indicates that one or more NI‑9770 input cards may be affected.

To isolate and resolve the issue:

1. Safely power down the system.
2. Remove one NI‑9770 card from the cRIO chassis and replace it by another one.
3. Restore power and monitor the signal behavior.
4. If the signal returns to normal, the removed card is likely faulty and should be replaced.
5. Repeat the process if multiple NI‑9770 cards are installed to identify the affected module.

Additional Information

To help prevent damage to NI‑9770 cards, ensure that RFCTs are properly insulated from ground. Grounding issues, particularly uninsulated GSU ground leads, can allow voltage spikes from the electrical grid to propagate into the measurement system.

Repeated or high‑energy voltage transients may damage the input LNA on NI‑9770 cards, leading to damage the Module or cRIO. Proper grounding practices and electrical isolation are strongly recommended to reduce the risk of recurring hardware failures.

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