While the world has seen a proliferation of smart wireless sensors in all sorts of applications, operators in the chemical, oil, and gas industries have so far been unable to fully benefit from this technology. These industries are generally associated with locations that contain hazardous levels of explosive gas, vapour, or dust mixtures. Either the available sensors were not suitable for these conditions or substantial investment and installation costs were associated with permanent remote monitoring solutions. As a result, there has been a considerable gap in the ability to monitor remotely the health and performance of machinery driven by electric motors.
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The situation has changed with ABB’s new-generation wireless smart sensor developed specifically for hazardous area applications. It enables operators to benefit from cost-effective condition monitoring without the associated safety risk. Condition monitoring, combined with advanced analytics in the cloud, provides an effective early warning that enables operators to identify potential issues and take appropriate maintenance action. This helps to eliminate the risk of costly, unplanned process downtime.
The ABB Ability Smart Sensor monitors key parameters of equipment such as motors and pumps to provide insights into their performance and health. Apart from being more sensitive to small changes in the condition of the equipment being monitored, this new generation smart sensor includes a faster microprocessor combined with expanded working memory and increased internal storage memory. These improvements enable the smart sensor to offer more monitoring capabilities, a broader communication range and exceptional battery life.
The sealed-for-life device, with IP66/67 protection ratings, can be mounted on equipment in a matter of minutes using a simple bracket. It can detect the high-frequency vibrations that are an early warning of bearing failure. However, unlike most equivalent sensors on the market, the ABB Smart Sensor not only measures vibration and temperature, but also the magnetic field - making it possible to measure the health and performance of motors with very high accuracy.
Deploying smart sensors in hazardous areas
Smart sensors enable equipment installed in difficult or dangerous-to-access locations to be monitored safely and remotely, keeping operators from being exposed to hazardous conditions. Also, by combining connectivity and data analytics, smart sensors allow users to plan their maintenance activities, cutting downtime, and extending equipment lifetimes
A prominent feature of the new sensor is its battery life, estimated to last three times longer than most competing designs. The use of long-life batteries offers an advantage over replaceable batteries, as replaceable batteries introduce the risk that the sensor’s dust, water and gas ingress protection might be compromised if the housing is not opened correctly or if a new battery is inserted incorrectly.
ABB uses a battery that limits internal current leakage over time, prevents soldered pads from breaking from vibrational forces, and keeps the power consumption low. This is made possible by ensuring that the battery and its soldered pads are enclosed in a holder and separated from primary heat sources by an air gap.
Using low-energy Bluetooth or WirelessHART, the sensor communicates with smartphones, tablets, PCs, and plant gateways. A new antenna design extends the transmission range by a factor of three to four, making reliable line-of-sight communications possible over distances of a few hundred meters.
The data collected by the sensors is transferred to a smartphone or gateway to a secure cloud-based server. Advanced algorithms based on ABB’s extensive experience with electric motors, analyse the data and convert it into insightful information on the equipment’s health and performance. Potential failure can be predicted allowing operators to take remedial action before a breakdown occurs.
Testing smart sensors for hazardous areas
Hazardous areas are generally classified according to two widely applied systems – the North American systems based on class, division and group, and the European/IEC systems based on class, zone, and group. Various national and international standards abide by either one of these two systems.
Globally available hazardous area-certified sensors, therefore, must comply with wide-ranging requirements set out in these and other standards. Some of the essential conditions are that internal hardware or an internal short circuit in the battery shall not cause heating or ignite a spark that can ignite gas. The sensor’s enclosure must also be robust enough to withstand the stresses associated with hazardous areas.
To verify the first condition, ABB’s engineers tested battery-powered sensors by short-circuiting the batteries to check if the resultant rise in temperature remains below the maximum limit of 135 °C (temperature class T4) defined by the standard. As heat is routed to the rest of the mechanical structure and absorbed by the plastics in the casing, the new smart sensors were well within the limit.
The second condition requires the new sensors to perform optimally under the most extreme environmental conditions. The target operating range of -40°C to +85°C is typical for most industrial electronic components. ABB engineers performed highly accelerated life tests (HALTs) to test the sturdiness of the sensor outside of the nominal operational window.
These tests subjected the sensor to cycles of high and low temperatures and through a combination of high vibrations and extreme temperatures. The results of the HALT tests indicated that the ABB sensor could survive a temperature range from - 70°C to 130°C, which is well beyond the original target. The sensor already has certifications for hazardous areas such as ATEX and IECEx and is currently completing certification for NEC and other local certifications.
Flexibility
The firmware and software in the new-generation smart sensor gives it the flexibility to be reconfigured easily to monitor various types of assets. For instance, a sensor could be reconfigured on the fly to act as either a pump sensor or motor sensor by selecting predefined or custom-made machine profiles.
Smart sensors for hazardous areas are already helping operators and maintenance teams to generate insights into the health of their key assets. This enables them to predict failures and take remedial action before a costly breakdown occurs. The ease of use smart sensors and their capability to generate a wide range of is set to play a key role in bringing digitalisation to the oil, gas and chemical processing industries.
The author, Teijo Karna is Smart Sensor Product Manager, ABB Motion.
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