Level limit switch
Series VN 1000 / 2000 / 5000 / 6000
Technical information / Instruction manual
page
Signal output and Diagnosis
Electronic module
8/16 mA or
4-20 mA
Output setting: 4-20 mA
The output states the quality of the vibration signal (amplitude) of the sensor. With the 4-20 mA setting it is
possible, to recognize material build up on the vibrating fork by evaluation with a PLC. Furthermore it is possible
to evaluate the vibration behaviour for critical applications by using a 4-20 mA Data logger or PLC.
Remark
In this mode:
•
The switch „D ON“ or „D OFF“ has no influence.
•
The LED „Signal output“ is off.
Output current:
•
20 mA:
The vibration amplitude is strong (safe measurement, clean fork). With interface measurement
(VN 10..0 und VN 50..0) a max. vibration amplitude of approx. 15 mA occurs.
•
< 20mA and >12/ 12.5mA:
The vibration amplitude is decreased by material build up or mechanical influence. On setting „Low
sensitivity“ the material build up must be more to decrease the output current compared to setting „High
sensitivity“.
•
<12/12.5 mA and >7/8 mA:
The recommended range indicate a weak vibration. This is also the range, where the internal LED
„Diagnosis“ starts blinking to indicate a weak vibration. Depending on the application this value can be
changed in the PLC.
The evaluation in the PLC should be done so, that a window between 12/12.5 mA and 7/8 mA is set.
The reaction to indicate „weak vibration“ should be delayed for approx. 10 seconds, so that the indicaton
does not happen when the vibration is stopped and is started during normal and safe measurement
operation.
A lag of 0.5 mA (between 12 mA and 12.5 mA) should be considered to avoid jittering of the output.
•
7/8 mA:
The recommended point to indicate a covered sensor. The point is close to the stop of the vibration at 6 mA.
Depending on the application this point can be changed in the PLC.
A delay of 1 mA (between 7mA and 8mA) should be considered to avoid jittering of output.
•
6 mA:
The vibration has fully stopped.
Increasing material build up
O
ut
p
ut
c
ur
re
nt
With setting „High sensitivity“:
With setting „Low sensitivity“:
Amplitude is 100%
Amplitude is 100%
Amplitude is 0%
Amplitude is 0%
Damping
by material
Vibranivo
®
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10
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12
VN 1000 / 2000 / 5000 / 6000 g
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