FEATURE SENSORS & SENSING SYSTEMS
MEASURING THERMAL GROWTH P
A manufacturer of diesel generating sets is using non-contact, eddy current displacement sensors from Micro-Epsilon to measure the thermal expansion of its engine bed frames
revious laser displacement sensors were proving to be unreliable due to
the ambient temperature fluctuations and the presence of oil and dirt. Micro- Epsilon’s eddy current sensors provided much superior performance. Mounted at predetermined locations on the genset, the eddy current sensors are performing reliably in important thermal growth tests including relative displacement measurements between the engine block and supporting bed frame. The engine bed frame is a critical part of a genset as it provides mechanical support for the engine, generator and other control systems. When the genset is running the bed
frame is subjected to high dynamic loads which create a significant amount of heat due to the diesel engine combustion process. The bed frame must therefore cater for any expansion of the engine block which is typically a few millimetres relative to the bed frame.
OPERATING IN HARSH CONDITIONS Prior to purchasing eddy current sensors the customer measured the thermal growth of engines using non-contact laser triangulation sensors. Although accurate, they were not sufficiently reliable when operating in the harsh conditions that the engines were tested in where dirt and oil are present. If the optical transmitter or receiver became dirty or smeared with oil the accuracy of measurements would suffer and results could be unreliable. Furthermore, the sensors needed to be mounted close to the engine block at a
distance of 10 to 30mm. The laser sensors were sensitive to temperature variations, particularly at the high end of the temperature scale. The customer therefore looked for an alternative displacement measurement sensor that was reliable and robust enough to cope with these harsh test conditions. After discussing their application with
Micro-Epsilon at a trade exhibition the customer was given a demonstration of the eddyNCDT 3001 eddy current displacement sensor. This sensor is an extremely compact, high performance eddy current sensor with integrated electronics. Although similar in size to a typical proximity or inductive sensor, its measuring performance is much greater, making it ideal for OEM applications. All conditioning electronics on the eddyNCDT 3001 are completely integrated into the sensor housing.
Although similar in size to a typical proximity or inductive sensor, its measuring performance is much greater
However, the compact M12 dimensions do not mean lower performance; the sensor’s temperature-compensated electronics provides high measurement stability (0.03% FSO) even in fluctuating ambient temperatures.
FACTORY CALIBRATED Most of its bed frame thermal growth tests require sensors that can measure to accuracies of 0.05mm which means the eddyNCDT 3001 was sufficient in this case. As well as costing less than a laser sensor the customer liked how the eddy current sensor was packaged including how compact, robust and integrated it was. The sensor can be cabled up directly to the customer’s test cell data acquisition unit, unlike the previous laser sensors which required an external power supply, resulting in additional cabling across the test cell. The eddyNCDT 3001 plugs in directly with one cable for power and data. The eddyNCDT 3001 is factory- calibrated for both ferrous and non- ferromagnetic materials which eliminates the need for any onsite calibration. The robust IP67 sensor design
combined with the true eddy current measuring principle enables measurements in harsh industrial environments where oil, pressure, dirt or dust may be present, as well as for offshore and marine applications. The sensor has a measuring range of 4mm and a frequency response of 5kHz (-3dB).
Micro-Epsilon T: 0151 355 6070
www.micro-epsilon.co.uk
SENSING CAPABILITY FOR LOGISTICS, WAREHOUSING AND GOODS HANDLING
SICK has set a technology milestone in sensing capability for logistics, warehousing and goods handling with the new PowerProx, offering unprecedented versatility to detect any object on a high-speed production line with just one range of sensors. SICK has achieved a step change in sensing performance and value by
packing the benefits of laser Time-of-Flight (ToF) technology into PowerProx’s compact housing to deliver high-performance distance sensing, proximity and object detection. A sensor in the PowerProx range can be used to replace most distance and proximity sensors in a goods handling facility. Engineers can choose from just four sensors to achieve highly accurate results over a wide distance range of 50mm to 3.8 metres. “Nothing gets by the SICK PowerProx,” says product manager for presence detection David Hannaby. “It has overtaken other market offerings to deliver a multi-tasking series of sensors with outstanding performance at a competitive price, achieving consistent results where a number of different specialised sensors would otherwise need to be used. “With PowerProx, even objects being conveyed at high speed, small and
14 SUMMER 2016 | IRISH MANUFACTURING
flat objects and goods with jet-black or shiny finishes can now be reliably detected over its extensive sensing distances. So a production engineer is offered the potential to replace most distance and proximity sensors in a store with a single range of sensors. The PowerProx is ready for use in the Industry 4.0 Smart Factory. The sensors can communicate their signals and results to a centralised factory network or be monitored, re-set or taught to perform new sensing tasks across a whole range of applications.” The precision of ToF laser technology when combined with SICK’s Advanced Background Suppression mean the PowerProx sensors offer a high degree of angular tolerance and are not affected by the ambient light or by dust, spray and particles. PowerProx operates according to the scanning principle so there is no need for reflectors or receivers. Easy to teach, the multitask sensor is adjusted via a potentiometer or
teach-in button. There are versions available with either 1 or 2 separately adjustable switching thresholds depending on the application.
SICK (UK) T: 01727 831121
www.sick.com/gb/en
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