SICK MPB10, Operating Instructions Manual

Page: 32 / 60

Alarm axis (Index 4531)
Only one axis of the indication values in the time range is monitored at a time; this can
be selected in Index 4531. Accordingly, the limit values in the time range are applied to
the selected axis, e.g. exceeding the limit value on the Z-axis does not trigger an alarm
when alarm axis Y is selected. For
a-RMS and v-RMS values, in addition to monitoring the
X-, Y- and Z-axes, the magnitude can also be selected as an alarm axis via Subindex 1.
Setting the limit values (Index 4532)
Minimum and maximum limits can be set for the following indication values:
Variance , Skewness , Kurtosis , Peak to peak , Shape factor , Crest factor , Impulse factor
Additional pre-maximum limits can be set for the following indication values:
a-RMS , v-RMS
The additional pre-maximum limit value makes it easy to map the different gravity
zones of ISO 10816-3. There is also the advantage that a status between good and bad
can also be defined via the pre-alarm, in which the machine should only be operated
with restrictions. In
figure 16 , it can be seen that the good machine condition (green)
is demarcated from the condition in restricted operation (yellow) via the pre-maximum
limit value. An imminent failure (red) can be delimited via the maximum limit value.
3
2
1
Figure 16: Pre-maximum and maximum limit value
1
Current vibration value
2
Maximum limit value
3
Pre-maximum limit
All limit values for the time range indication values can be defined via Index 4532, the
corresponding alarms are output via Index 4533.
9.3.1.1 a-RMS (Index 4483-4485)
The following mechanical faults have a strong influence on the a-RMS :
• Friction
• Touching machine components
• Unbalance
• Wear
• Lubricant complications
In addition to the a-RMS value of the individual axes (X/Y and Z), the sensor provides
the magnitude, the effective value of the sum vector of all three axes. The magnitude
thus represents the energy contained in the vibration without directional separation.
9.3.1.2 v-RMS (Index 4483-4485)
The v-RMS changes significantly, especially for the following fault conditions:
9
OPERATION
32 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