Measurement Computing eZ-Analyst rev.14.1 - Manual (Page 23)

eZ-Analyst 878193 Menus 3-5
An Example of Auto-Ranging
Maximum FSV set at 25.7 V
Minimum FSV set at 0.2 V
Upper Limit set at 90%
Lower Limit set at 10%
Increasing Factor set at 1.5
Decreasing Factor set at 1
In this example we have set the radio button for
Current FSV instead of Minimum or Maximum
(note 2). The starting value, in the example, is 0.20 V.
In the first iteration we see
that we have a peak of 0.19 V.
This falls outside of our band of
0.02 to 0.18 V that was
established by our upper and
lower limit percentages; i.e.,
90% of the Current FSV and
10% of the FSV.
An Example of Auto-Ranging
As a result, the Current FSV is increased by a factor of 1.5 (our Increasing Factor) and the
Current FSV becomes 0.30 V. Our limits, in volts, also changed since we are now looking
at percentages of 0.30 volts instead of the same percentages of 0.20 volts.
In the second iteration of our example, we see a 0.22 volt peak. This value is within our
established limits so the Current FSV does not change.
Note 1: If the Capture Mode is the Input Channel (Trigger Mode), the Auto Range process waits for a
trigger.
Note 2: A Start FSV of Minimum or Maximum can selected instead of Current FSV, as in our example.
Minimum FSV is the default.
Task Menu > Calibration
When calibration is performed, a signal of known Peak level [or RMS value] is supplied to a
transducer that is connected to an active input channel. An accelerometer calibrator or piston
phone is typically used to generate the calibration signal for vibration sensors and microphones,
respectively.
Examples:
Accelerometer calibrators typically make use of linear engineering
units and, as their name implies, are used for calibrating
accelerometers.
Piston phones are most often used for calibrating microphones. Piston
phones typically make use of decibel (dB) engineering units.
eZ-Analyst includes a Calibration window for selecting the channels to be calibrated and for
entering several signal-related parameters. In addition, the calibration is actually started from
the window.