Meggitt vibro-meter SpeedSys300 ODS301, User Manual

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USER MANUAL Document reference MAODS301/E
SpeedSys300 ODS301 overspeed detection system Edition 4 - May 2022
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System overview
INTRODUCTION TO THE SPEEDSYS300 ODS301 OVERSPEED DETECTION SYSTEM
The SpeedSys300 ODS301 overspeed detection system is a fundamentally simple and
highly robust system, designed for ease of use and reliable operation, with an exceptionally
long proof-test interval of typically 10 years.
In operation, a shaft with a multi-toothed speed sensing surface, known as a speed wheel, is
monitored by an industry-standard proximity, electronic or magnetic speed sensor. The
sensor / measurement chain pulses (frequency) are counted by the SpeedSys300 ODS301
module and converted to a rotational speed measurement and an acceleration
measurement.
The SpeedSys300 ODS301 module then compares the speed and acceleration
measurements against the configured alarm limits, and will activate the safety relays – relay 1
and relay 2 – and additional (non-safety) relays – relay 3 and relay 4 – should a measurement
exceed a limit. In general, the safety relays are used for critical alarms and the additional
relays are used for non-critical alarms or other alarm/status information for the module.
The SpeedSys300 ODS301 module also uses the measured shaft rotational speed to drive
the analogue 4 to 20 mA current loop output and update the frequency (speed) output, so that
the information can be shared with external third-party systems such as a DCS or PLC, or
even a simple display.
NOTE: The safety relays – relay 1 and relay 2 – and the analog output (4 to 20 mA) are
safety outputs. More specifically, they are SIL certified and can be used for critical
functions in machinery protection applications, such as initiating the shutdown (trip)
of a machine.
Figure 1-1 illustrates the SpeedSys300 ODS301 module’s hardware interfaces.