Cross Channel Phase collects spectra to determine the phase shift and coherence relationships between two sensor locations. Coherence compares two sensor signals and determines if the vibration is related and confirms the quality of the data. A value near 1.0 indicates there is some cross vibration from other equipment.
Cross Channel Phase can monitor a single frequency or acquire full spectral plots.
|Misalignment||Measure across a coupling.|
|Looseness/weakness||Measure across mechanical interface.|
|Coherence||One sensor on each machine.|
- Create a job.
- From the Analyze main menu, press .
- Use the up and down arrow keys to select Cross Channel Phase.
The Analyze Setup screen appears.
Set the following options as necessary.
Option Description F2 Set Spectra Params Set the Fmax, Fmin, and lines of resolution. See Fmax and Fmin and Lines of resolution. F3 Set Freq In Single Frequency mode, enter a value between 0 and 80,000 to set the phase frequency to calculate the cross channel phase and coherence. This option appears in Single Frequency mode only. The default is 60 Hz. F3 Set Average Count In Full Spectrum mode, enter a value between 0 and 10,000 to set the number of averages to collect. Enter 0 to collect data until you press Stop. This option appears in Full Spectrum mode only. The default is 1. F4 Set Window In Full Spectrum mode, select either the Hanning or Uniform window. See Windows. This option appears in Full Spectrum mode only. The default is Hanning. F5 Set Mode Single Frequency calculates the cross power phase relationship between the channels at a frequency, and calculates a coherence value for this relationship. In Full Spectrum mode, two or four channel spectral data is collected with a specified number of averages and plots the phase, coherence, as well as the spectral data for each channel. The default is Full Spectrum. F7 Tach Setup Set up the tachometer parameters. See Set up a tachometer in Analyze. F11 Ref Input Select the input to use as your reference. If you disable the reference input from the Input Setup screen, "???" appears until you press F11 Ref Input. F12 Input Setup Set up the input channels, the sensor type, and the units for the acquisition type.
Enter to collect the data.
One or more plots display the data.
- Press F2 Next Response Input to display data for the next response, if you set up more than two inputs.
If necessary, press
F8 Start to redo the measurement.
Note: You cannot store the data.