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Operating Manual
MHM-97442
Note
All functions, exclusively assigned to the detection of rotational direction, measure only up
to a signal frequency of 166 Hz. At higher speeds the detected rotational direction is
"frozen" and activated again with signal frequencies below 166 Hz.
This parameter is grayed out if VR has been selected for parameter Sensor Input → Sensor
type.
Acceleration response time
Because of a short measuring time, the indication of acceleration values may vary. Define a
time constant at a range of 0 to 5 seconds to smoothen the acceleration indication. The
time constant defines the time that it takes for the system to reach 63% of the asymptotic
end value. After a delay of 5 times Acceleration response time the asymptotic end value is
reached. This parameter influences current outputs assigned to the characteristic value
Acceleration and digital outputs assigned to function ... Acceleration limit value .... For
stable measurements Emerson recommends using a time constant >0.1 seconds and the
measuring mode 1 x per revolution. If this parameter is set to "0", the indication is not
smoothed.
Group Measuring range
Maximum speed
Enter here the maximum speed for the measurement. The voltage range for the analog
comparison is scaled on this speed range (0 to Maximum speed). Beside this, the
maximum value for the trip level depends on this parameter.
Note
The maximum speed value for the trip level depends on this parameter. The trip limit value
must be at least 67 % of the maximum speed.
Minimum speed
This entry field is only active if VR has been selected for parameter Sensor Input → Sensor
type. Enter here the minimum speed for the measurement. The value must be between 0
and 30% of the maximum speed (parameter Maximum speed). Use this parameter if the
machine can not be started because of an analog error.
The signal amplitude, generated by VR sensors, depends mainly on the machine speed.
The signal amplitude of the three sensors can be different because of slightly different
mounting distances between the VR sensors and the trigger wheel. This can cause an
analog error at a slow rotating machine.
Group Equipment parameter
Type of measurement (Pulse shape)
Certain functions such as detection of the rotational direction and pulse comparison
depend on the shape of the measured signal. The signal shape depends on the design of
the trigger wheel. Select here the type of the user trigger wheel shape.
•
Choose Pulse wheel if the used trigger wheel has a rectangular tooth profile.
•
Choose Gear wheel if the teeth of the used trigger wheel have chamfered flanks.
MHM-97442, Rev. 2.06
Configuration
February 2023
103
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