Safety Function And Safe State - Pepperl+Fuchs SIL VIM8 Series Manual

Functional Safety Vibration Sensor VIM8*
Planning
3.2

Safety Function and Safe State

Safe State
In the event of a fault that cannot be corrected (e. g. hardware defect, or vibration in resonance
with the sensor), the sensor will switch to the safe state. This state can only be exited
by power cycling.
The safe state can be recognized when all 3 of the following occur at the same time
• All status LEDs are switched (red, yellow, green).
• All switching contacts are opened (low level).
• Current output is set to 0 mA.
Safety Function
Device with Pre-Alarm and Main Alarm
The system includes 3 safety functions:
1. If the measured vibration variable exceeds the threshold value set for the pre-alarm
for longer than the set delay period, the pre-alarm relay will open.
2. If the measured vibration variable exceeds the threshold value set for the main alarm
for longer than the set delay period, the main alarm relay will open.
3. The analog current output depicts the vibration variable measured in the interval
between 4 mA and 20 mA. The vibration variable is the vibration speed.
Device with Window Function
The system includes 3 safety functions:
1. If the measured vibration variable falls below the lower limit value
of the switching threshold LIM1 of the window area for longer than the set delay period,
the relay will open.
2. If the measured vibration variable exceeds the upper limit value
of the switching threshold LIM2 of the window area for longer than the set delay period,
the relay will open.
3. The analog current output depicts the vibration variable measured in the interval
between 4 mA and 20 mA. The vibration variable is the vibration acceleration.
Note
The next control device must trigger the shutdown should the current output deliver
more than 20 mA.
Note
See corresponding datasheets for further information.
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