The vibration monitoring system consists of an EM-82 accelerometer and an EM-72 sensor supply and monitoring unit. Together they provide vibration measurement, signal filtering, sensor supervision and adjustable warning and alarm functions.
The monitored quantity can be selected as either acceleration or vibration velocity. Adjustable high-pass and low-pass filters allow the system to focus on the frequency range relevant to the monitored machine or process.
The EM-82 is a capacitive single-chip accelerometer housed in a lightweight alloy enclosure with IP67 protection.
The sensor design provides good long-term repeatability, shock resistance, temperature stability and a linear frequency response. An integrated output buffer amplifies the sensor signal and improves resistance to interference when longer connecting cables are used.
The accelerometer is available in two measuring-range versions for different vibration levels.
The EM-72 supplies the accelerometer with its required operating voltage and monitors the sensor output. Abnormal sensor voltage can be used to detect faults in the accelerometer or its connecting cable.
The monitoring unit can process the sensor signal as either:
Selectable second-order high-pass and low-pass filters allow the monitored frequency band to be adapted to the application.
Available low-pass filter frequencies are:
Available high-pass filter frequencies are:
Using both filters creates a selectable monitoring band that can reduce unwanted low-frequency movement and high-frequency noise.
The filtered vibration signal is processed by an RMS detector. The resulting DC level represents the measured vibration amplitude.
Adjustable warning and alarm thresholds allow the system to signal when the vibration level exceeds the selected limits. The alarm functions can be disabled using the alarm-block input.
The EM-72 provides the following outputs:
The waveform output can be used for external measurement or signal analysis. The current output represents the calculated RMS vibration level.
System settings are configured using rotary selectors and clearly marked DIP switches. These settings include the monitored quantity, filter frequencies and warning or alarm levels.
| EM-72 supply alternatives | 230 VAC or 24 VDC ±15% |
|---|---|
| Current consumption | 50 mA or 150 mA, depending on version |
| Compatible accelerometers | EM-82-05 or EM-82-50 |
| Accelerometer supply | 12 V, max. 15 mA |
| Monitored quantities | Vibration velocity or acceleration |
| Low-pass filter | 12, 25, 50, 100, 200, 400, 800 or 1600 Hz; second order |
| High-pass filter | 3, 6, 12, 25, 50, 100, 200 or 400 Hz; second order |
| Velocity monitoring range, EM-82-05 | 1–50 mm/s |
| Acceleration monitoring range, EM-82-05 | 1–50 m/s² |
| Velocity monitoring range, EM-82-50 | 10–500 mm/s |
| Acceleration monitoring range, EM-82-50 | 10–500 m/s² |
| Vibration-level output | 4–17 mA = 0–100% |
| Current-output load | 0–300 Ω |
| Velocity waveform output, EM-82-05 | 400 mV per mm/s |
| Acceleration waveform output, EM-82-05 | 400 mV per m/s² |
| Velocity waveform output, EM-82-50 | 40 mV per mm/s |
| Acceleration waveform output, EM-82-50 | 40 mV per m/s² |
| EM-82 housing protection | IP67 |
| EM-72 housing protection | IP65 polycarbonate housing |
| Housing dimensions, version 1 | 125 × 125 × 75 mm |
| Housing dimensions, version 2 | 140 × 140 × 75 mm |
| Operating ambient temperature | 0 … +60 °C |
| Weight | Approx. 200 g |
Ordering larger quantities +100pcs.
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