1
2
3
4
5
Figure 20: Peak detection frequency analysis
Monitoring in the standard analysis
For monitoring purposes, the relevant ranges in which peaks are expected are defined
by their center frequency in Index 4566 and the associated frequency ranges in Index
4567. Once these peak frequency ranges are defined, the associated maximum and
minimum values can be read out since the last reset.
NOTE
If no peak frequency ranges are defined, no maximum and minimum values since reset
are output in Index 4556-4558.
For each defined peak range, an upper and lower limit value for the amplitude of the
peak can be defined. If the amplitude of a monitored peak is greater than the defined
upper limit value, this is output via an alarm bit in Index 4575 in the corresponding
subindex. If the amplitude of a monitored peak is smaller than the lower limit value or if
the peak is no longer detected, this is output via an alarm bit in Index 4576.
A negative amplitude limit value ensures deactivation of the alarm. This means, for
example, a peak can fall completely below the noise when the lower limit is deactivated
without triggering an alarm.
In addition to the peak frequency ranges, the frequency ranges in between are also
monitored. If the frequency of a peak changes beyond the defined peak frequency
range or if a new peak occurs in such an intermediate range, a corresponding alarm bit
is output in Index 4577. There is one more intermediate range that is monitored than
defined peak frequency ranges. Here, the first range extends from 0 Hz to the beginning
of the first peak frequency range. The rest lie between the defined peak ranges. The
last range covers the frequencies above the last peak range. A newly occurring peak
in such an intermediate range is typically an indication of a fault condition on the
monitored machine.
Manually setting the limits
Setting the limits manually requires a close look at the frequencies and associated
amplitudes that occur. This is usually very time-consuming, but can be bypassed via
the automatic teach-in process. The position of the 16 frequency ranges is defined
by their center frequencies in Index 4566 and their width by the tolerance of the
9
OPERATION
38
O P E R A T I N G I N S T R U C T I O N S | MPB10
8028041/2022-08-16 | SICK
Subject to change without notice
