6.6 Power user tips

Finally, let us share some advice for the power user in Analyze.

• Use mode Magnitude combined with Averaging Maximum for a low-frequency range such as 0 – 20 Hz. This quickly reveals any FRF with a low-frequency problem, for instance, caused by base strain sensitivity or a floating DC value.

• When (still) connected to the MKII, try making an impact in Analyze in Measured mode. You will get a dialog asking if you really intended to measure in Analyze or accidentally triggered a recording. When confirmed, it unlocks a whole new way of FRF measuring: a mode in which new measurements are added to the currently selected column. This can be an extremely rewarding exercise for when the whole impact list has been completed: you can optimize the FRF coherence matrix as a whole by adding additional impacts for just these positions that need them. That being said, the Analyze mode does not provide the diagnostics that Measure does, so it needs to be used with care.
• DIRAC provides unlimited freedom to move back and forth the Prepare, Measure (or Data) and Analyze modules. This allows to add additional impacts on the fly in Prepare, make measurements in Measure, and review them in Analyze. Or, after performing the first impact in a campaign, switch to Analyze to check the ODS at a low frequency and troubleshoot any misplaced sensors.