Feature: Industrial electronics
condition, to expensive repairs, and even catastrophic failures of a system or even a production line. Here we will discuss the challenges designers face in condition-
monitoring applications, and how to best address them, without increasing the cost of the design.
Condition monitoring Condition monitoring overcomes the problems of preventative maintenance schedules for large and complex machinery and processes. Te method relies on knowing the status of machine components to be serviced or replaced well before failure occurs. For example, by constantly monitoring the vibrations of a motor, soſtware can determine the wear state of the motor’s bearings and predict a breakdown. Te information then allows engineers to extend service intervals whilst avoiding unplanned downtime; see Figure 1. IIoT sensors are a good option for condition-monitoring
applications. Tese compact devices can be attached to a machine or failure point to enhance measurement precision. Wireless connectivity allows for regular condition updates without expensive wiring.
Building power supplies for battery- powered IIoT sensors
By Rolf Horn, Applications Engineer, Digi-Key Electronics
P
owering low-power wireless IIoT sensors for industrial applications, such as machine condition monitoring, is a considerable task, due to the harsh operational environments. Sensitive monitoring devices must be supplied with a steady, clean DC voltage and be protected against
the voltage surges common to industrial equipment. In addition, space is typically at a premium, and costs must be kept down. Te sensors must be compact, robust, easy to use and inexpensive, yet work reliably for a long time, with little or no maintenance. Sensor failures range from missing vital data about the machine’s
20 September 2022
www.electronicsworld.co.uk
Rugged power supplies To design a power supply for IIoT sensors can be a tough task. Industrial environments are typically dirty, with vibrations, high temperatures and voltages, humidity and other challenges. Space is oſten at a premium, and yet the sensitive electronics demands a continuous, clean and precisely-regulated DC voltages. Packaging advances, such as incorporating power and control
elements on the same piece of silicon and using low-profile transformers, enable manufacturers to offer high-specification isolated DC-DC converters for IIoT sensor applications. One example is Recom Power’s DC-DC converters, which use planar-type transformers to reduce chip heights to under 3mm; see Figure 2. Teir compact size allows for power regulation to be placed much closer to the load, simplifying and shrinking the overall design. Te use of standard SOIC-16 packaging allows handling and assembly with automated equipment, too. Recom Power’s DC-DC converters have no minimum load
requirement, making them suitable for applications that oſten switch into very light load operation modes to conserve energy – commonly found with IIoT sensors. Te environment around the IIoT node is subject to high power
surges whenever heavy machinery is started or stopped. For safety reasons and to protect fragile electronics, the sensor’s DC power supplies require isolation from the main supply. Recom Power DC-DC converters use an internal transformer to isolate the output from the input. Figure 3 shows an application circuit for the isolated DC-DC converter.
Thermal management Te energy density of a DC-DC converter is measured in Watts per cubic centimeter (W/cm3
). Higher power density allows designers to increase the power available for the application without
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