Stand-alone 4-20 mA vibration displacement sensor for machinery monitoring

Wilcoxon Research, a supplier of vibration sensors and sensor networks, announced the addition of a displacement sensor to its popular PC420 Series of 4-20 mA vibration sensors.
By Control Engineering Staff May 28, 2008

Germantown, MD –– Wilcoxon Research, a supplier of vibration sensors and sensor networks, announced the addition of a displacement sensor to its popular PC420 Series of 4-20 mA vibration sensors. The company says its PC420D is the first IEPE displacement transducer and 4-20 mA vibration transmitter packaged as a single sensor.
The company says its sensors monitor rotating equipment and outputs a real-time 4-20 mA signal proportional to the vibration level. By trending this real time data, plant personnel are able to schedule preventative maintenance activities around planned downtime, saving time and money on costly unexpected repairs. A white paper about displacement monitoring is available from the

Wilcoxon Research knowledge desk

.
The 4-20 mA output is determined by first measuring the peak to peak vibration, then converting that level to a 4-20 mA signal, according to the company. Because balance components tend to dominate the vibration spectrum when viewed in displacement units, the PC420D sensor is able to track machines’ balance vibration component, which the company says is one of the most sought after parameters. Integrating this signal into an existing PLC, DCS or SCADA system simplifies real time health monitoring because vibration, formerly considered too complex, can be trended in easily understood millimeters of displacement.
Measuring displacement can unmask hidden problems and provide data in easy to understand measurement units, says the company. Instead of converting to displacement after the measurement is taken, a common practice in diagnostic vibration monitoring systems that can introduce errors known as “ski slopes,” the sensor integrates at the measurement point for the cleanest vibration data.
The company says its sensor is ideal for condition based monitoring and predictive maintenance of motors in the speed (frequency) range of 300 rpm to 60,000 rpm (5 Hz to 1,000 Hz). The sensor can be used to monitor balance of plant instrumentation such as pump motors, blowers, fan motors, compressor motors, and a wide variety of machine tool drive motors to significantly reduce failure rates in the field.
— Edited by C.G. Masi , senior editor
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