FEATURE SENSORS IoT put to good use

Fabrizio Vitali, business development manager Europe for automation at Omron Electronic Components Europe explores effective remote thermal management of electrical systems

thermopile, custom designed sensor ASIC and signal processing microprocessor and algorithm into tiny package, the D6T is believed to offer the highest signal-to- noise ratio (SNR) in the industry. This ensures clear, reliable measurements that can readily be interpreted by the system. A key advantage of the integrated signal processing microprocessor is the fully linear output (figure. By pre-processing the signal on the module, the D6T converts the sensor signal to a digital temperature output giving a straightforward interface to a microcontroller, simplifying the system integrator’s task. Alternative devices do not provide a temperature output, so the designer needs to implement a signal processing algorithm to convert the output to temperature. The space saving design of the D6T, at

only 14 x 8 x 8.93mm for the largest 32 x 32 element version, makes it exceptionally well suited for installation in a panel or system. Its field of view of 90.0° by 90.0° encompasses an area of


o operate reliably and safely in remote locations, industrial

automation systems and other electrical installations need their thermal status to be fully and constantly monitored. An abnormal increase in temperature is frequently an early indication of a fault condition and needs to be addressed before the system is damaged or worse still, combusts. Increases can take the form of

individual ‘hot spots’ where parts of a panel or individual components are operating close to or above a safe temperature and rises in the ambient temperature. The first can be due to a fault condition, such as a short circuit, or by a component such as a transformer running at peak load for lengthy periods. The second can be caused by the operating environment (prolonged exposure to intense sunlight), or a failure of cooling components such as fans. Both are a threat. The goal of maintenance over the

Internet of Things (IoT) is to ensure “zero down time” and eliminate unforeseen device failures that can lead to serious accidents or unplanned facility stops. To achieve this, the temperature of

every panel in a plant as well as the surrounding ambient temperature needs to be monitored continuously using appropriate sensor solutions. Real-time remote monitoring in this way ensures that the need for site visits is kept to an absolute minimum. Sometimes the fault can be rectified remotely, perhaps by reducing power demand from the system to allow key components to cool. Other times an engineer site visit is needed, for


example to replace a faulty component or to repair a short circuit. Monitoring of the temperature of the

whole cabinet in which the system is housed is essential but by itself clearly insufficient: a component can be running dangerously hot and be in danger of meltdown or combustion without affecting the overall temperature of the system. On the other hand, attaching an individual temperature sensor to each electrical component is completely impractical – a wiring loom for example can develop hotspots almost anywhere. New wide-angle thermal image sensors

that can detect hotspots in large areas of a system such as a whole panel, provide a great starting point for the truly effective remote thermal management of electrical systems. Complemented by ambient temperature sensors and air velocity sensors to verify the correct operation of cooling fans, they can provide a complete IoT based thermal monitoring and remote maintenance solution.

WIDE-ANGLE THERMAL SENSORS New infrared thermal sensors with a wide viewing angle in a compact body highlight hotspots anywhere in their field of view, filling the gap between taking an ‘average’ value of the temperature of the whole system and taking a reading of the temperature at one or two selected points (Figure 1). Omron D6T MEMS thermal (IR) sensors

measure the surface temperature of objects without touching them using a thermopile element that absorbs radiated energy from the target object. Incorporating a state-of-the-art MEMS

Figure 1: A wide-angle IR sensor such as the Omron D6T 32x32 can monitor for hot spots across a wide area such as a panel

200cm x 200cm from 1 meter distance, providing contactless measurement of temperatures of 0-200ºC in ambient temperatures of -10-70ºC. For smaller systems requiring a more restricted field of view, a suitable alternative is the 1x8 D6T-8L-09H or the 4x4 D6T-44L-06H, offering 54.5° x 5.5° and 44.2° by 45.7° respectively. At 1 meter distance; the field of view of these devices is 10cm x 103cm and 81cm x 84cm respectively. There is also the single element Omron D6T-1A-02 which has a viewing angle of just 26.5° x 26.5° translating to an area of 47x47cm at a distance of 1 meter, giving a highly directional characteristic. Whilst these sensors will identify

specific hot spots, there remains a need to monitor the ambient temperature of the system as a whole. A high ambient temperature can be the reason why parts of the system are threatening to overheat and can by itself cause it to malfunction. Compact multi-purpose environmental sensors make it very easy for the designer to deliver a wide range of measurement functions including temperature, humidity, air quality, light, barometric pressure, noise and acceleration from just one small sensor.


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46