Emerson EPRO MMS 6140 Absolute Rotor Vibration Monitor

Features:

• Part of the MMS 6000 Machine Monitoring System
• For connection of one eddy current sensor and one seismic or piezo-electric transducer.
• Signal frequency ranges 1…250 resp. 5….2000 Hz
• Both channels may also be used in single-channel mode, channel 1 for shaft vibration and channel 2 for bearing vibration.
• Measuring results of both channels to be combined with each other for calculation of the absolute shaft vibration.
• Sensor supply balanced to ground to suppress disturbances in industrial environments
• RS 232 interface for configuration and reading out of measuring results
• RS 485 interface for connection to epro’s MMS 6800 analysis and diagnosis system or to host computers

Applications:

The MMS 6140 dual-channel monitor has been designed for the use with two different transducers. Channel 1 operates with eddy current sensors and channel 2 with seismic or piezoelectric sensors. Each measuring channel can operate separately or the results of both channels may be used to calculate the difference. By means of calculating the difference of these signals, the absolute shaft vibration results. At the MMS 6140 monitor the relative shaft vibration is measured with an eddy current sensor and the absolute bearing vibration with a seismic or piezo-electric sensor. The phase shift between the signals, caused by the different measuring principles, is compensated by the electronics. In the following, the bearing vibration signal is subtracted from the shaft vibration signal. The time signal arising thereof is then processed like a normal vibration signal, converted to a characteristically value according to the configuration parameters, output as current signal and supervised on limit exceedings.

The measurement of absolute shaft vibrations serves the construction of turbine protection systems. They provide signals for analysis and diagnosis systems to be further processed in field bus systems and networks. Such cards of the MMS 6000 family are suitable to build up systems for increasing performance, efficiency and safety of operation and to extend the machines’ life times. Application fields of the epro measuring amplifiers are steam, gas and water turbines, compressors, fans, centrifuges and other turbo machinery.

Technical Data:

• Open circuit and closed circuit mode
• Channel or module inhibit
• Measuring range multiplier to modify the alarm limits during run-up or run-down; adjustable within 1.000 to 4.999; 24 V logic.
• Input resistance: ≥ 30 kΩ
• Key pulse input: 1 pulse per revolution for analysis purposes of the system: 24 V Logic
• Input resistance: > 30 kΩ
• Pulse duration: min. 10µs (edge-triggered)
• Voltage inputs: 0…10 V; (Two, one for each channel)
• Input impedance: > 100 kΩ
• Resolution: 10 bit

Sensor Inputs:

• Two independent sensor inputs. Channel 1 for eddy current sensors, channel 2 for seismic or piezo-electric sensors.
• The signal inputs are differential inputs, galvanically isolated from the system supply, open circuit and short circuit proof.

Channel 1 (Eddy Current Sensors):

• Input impedance: ≥ 100 kΩ
• Input voltage range: -1…-23 V
• Signal frequency range: 1/5…50…2000 Hz
• Signal voltage range: minimum range: 0… 400 mVpp maximum range: 0…2000 mVpp freely configurable
• Sensor supply: The sensors has an individual supply output, galvanically separated from all system voltages and the power supply of the monitor and is open circuit and short-circuit proof.
• Parallel connection with other modules possible without mutual influences.
• Nominal voltage: -26,7 V
• Available output current: typ. 20 mA / max. 35 mA

Channel 2 (Seismic / Piezo-electric):

• Input impedance: ≥ 100 kΩ
• Input voltage range: -5…+15 V
• Signal frequency range: 5/10…50…1000/1600 Hz according to VDI 2056 / DIN 45666 / ISO 3945; 10…1000 Hz with corresponding filter characteristics
• Signal voltage range: minimum range: 311 mVpp maximum range: 9500 mVpp freely configurable
• Sensor supply when operating with piezo-electric transducer: Galvanically separated from the supply voltage, open circuit and short-circuit proof.
• Current range: 0…8 mA; programmable in steps of 40 µ A
• Accuracy: ±0.5% of the measuring range; 0.5% of the adjusted value
• Permissible load: ≥ 3,4 kΩ bei 8 mA ≥ 13,6 kΩ bei 2 mA

Control Inputs:

• Common logical binary inputs for both channels.
• For choosing the operating mode of the limit values for „warning“ and „danger“

For more information, please read or download the MMS 6140 PDF online ： mms6140e

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