Question
During a CMWrun test my DUT fails on delivering isolated measurements using CMW270/290/500.
Debugging CMWrun Test Plan Hints
Answer
From time to time it is possible that CMWrun test plans fails on isolated areas in the report. This can be observed sometimes when the report delivers measurements following some of below return values.
Return Values NCAP, NAV and INV
If no valid result is available, the value returned by FETCh, READ and CALCulate commands depends on the reason for the unavailability. Possible values are NCAP ("not captured"), NAV ("not available") and INV ("invalid"). For each unavailable result value, one of these values is returned.
The following table provides some examples
| Situation | Returned value |
|---|---|
| Measurement state OFF | NAV returned by FETCh and CALCulate |
| Disabled view | NCAP returned by FETCh and CALCulate |
|
Unsuitable settings for a certain part of the measurement. Example: The measurement of some results requires a specific trigger type. |
NCAP returned |
| Object to be measured not available in signal (for example, certain physical channel missing) | NCAP returned |
| Underflow, overflow, sync error, trigger timeout | INV returned |
Below guidelines should help to run the proper troubleshooting.
- Revise the CMWrun logs and reports typically saved under C:\Users\SMITH\Documents\CMWrun Files.
- Make sure the right attenuation settings and Expected Nominal Power have been selected for the applied scenario.
- Add SYSTem:DISPlay:UPDate 1 command to the test plan, this avoids the GUI screen to freeze during test plan execution. This helps while running the test plan in steps to observe and monitor the delivery of results. With an available LAN connection, one could use the Windows Remote desktop to monitor the test plan and GUI in parallel.
- Once a particular part of the test plan has been isolated where a measurement fails, apply a breakpoint in CMWrun and continue the test via the GUI. At this point the “Measurement on Exception” functionality could be crucial to verify the validity of the incoming signal. This forces the measurement even if the power level or trigger settings are not sufficient.
- Revise CMWrun test plan limits where applicable to relax the limits driving the fail.
References
- CMWRun GUI Embedded Help
- CMW270/290/500 Embedded Help
- Gloris related CMW Family Literature
