VibroSystM DMV-100, Installation Manual

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39 DMV-100 Rotor Creep and Speed Detector - Installation Manual
5.4 Initial setup of the DMV-100 System
5.4.1 Preliminary considerations
A minimum of setup may be required on the Speed Indicator before use. A setup is needed for correct display
of RPM information based on the number of poles of the monitored machine. As well, to ensure accuracy, the
indicator must be programmed to a specific RPM range.
5.4.1.1 Pole detection functional aspect
For each passage of a pole, the conditioner transmits an impulsion (1/pole pulse) that is read by the speed
indicator. The speed indicator measures the frequency of the impulsions and then converts it into RPM. Pole
detection by the conditioner derives from hysteresis detection:
- minimum hysteresis is the proximity at which pole detection occurs
- maximum hysteresis is the maximal air gap value that can be associated with a pole and marks the
end of pole detection
The conditioner transmits an impulsion as soon as the maximum hysteresis value is exceeded, and the
measured air gap value must become lower than the minimum hysteresis value in order to validate the next
maximum hysteresis value.
Figure 36 : Hysteresis identification
The minimum and maximum hysteresis values are factory preset to 46,6 mm and 45,3 mm.