Rockwell Automation 1440-DYN02-01RJ XM Dynamic Measurement Module - Manuel (Page 67)

Publication ICM-UM002F-EN-E - March 2013 67
Configure XM Module in RSLogix 5000 Software Chapter 3
Full Scale Choose the maximum signal level expected to be
processed by the channel. If the full scale value is peak
or peak-to-peak, select the measurement performed
(true or calculated) to produce the overall value. The default value and the available values
depend on the
Nominal Sensitivity selection.
True The actual or literal measure of the signal. It is the
maximum peak in the sample (time waveform) for pk
measurements, or the difference between the
maximum and minimum peaks for pk-pk
measurements. These parameters are dimmed when full scale
is set to an RMS value.
Note: For a pure sine wave, the true and
calculated values are equal. The true and
calculated values will diverge as additional
signals are added to the waveform, or as
non-sinusoidal or non-repetitive signals are
included.
For protection applications where the
objective is to preclude contact between
stationary and moving components, True is the
appropriate measurement since it is a better
indication of actual movement.
For conditioning monitoring applications
where the objective is to indicate the total
energy in the system (that is the overall value),
Calculated is the preferable measurement.
Calculated The RMS value of the sample (time waveform)
multiplied by the square root of two (1.414) if
measuring the peak value, or two times the square
root of two (2.828) if measuring the peak-to-peak
value.
High-Pass Filter Corner Choose the high pass filter to apply to the
measurement.
• 0.2 Hz
• 1 Hz
• 5 Hz
• 10 Hz
• 40 Hz
The high pass filter is useful in removing low
frequency signal components that might
dominate the signal, particularly when
integrating. The high pass filter attenuates all
frequencies below the filtered frequency. It
allows, or passes, frequencies above the
defined frequency.
In this field Values are Comments
IMPORTANT
When full scale is set to an
RMS value, including
Calculated Pk or Calculated
Pk-Pk, the XM module is
configured to accept input
signals as high as 6X the
specified full scale without
saturating the electronics. This
is because a signal with
moderate RMS value may have
very high spikes because RMS
is an averaging mechanism. If
True Pk or True Pk-Pk is
selected, the module is
configured to spread the full
scale range over the entire
measurement range, without
reserving this 6X headroom
used for RMS. This gives better
resolution within the full scale
range but causes the signals to
be clipped at levels just above
the full scale.