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IIoT for electric actuators: How cloud solutions facilitate predictive maintenance

With the help of modern cloud solutions, managers of hydropower plants can use data from their actuators to enable predictive, condition-based maintenance of actuators, valves and penstocks, ...

... optimize their operations and ensure long-term plant availability. Today, cloud-based solutions make it increasingly easy to exchange and analyse the vast amounts of data available from intelligent field devices. The Industrial Internet of Things (IIoT) empowers the development of new solutions to take advantage of this wealth of data to optimize processes, avoid downtime, cut costs and increase plant availability. These are key advantages for hydropower plants, dams and pipelines, where remote monitoring and unattended operation are common, and plant availability is critical during times of peak power demand. Thanks to their built-in intelligence, electric actuators are ideally suited to IIoT applications. Modern electric actuators are not only robust and reliable; they also come with built-in sensors, flexible communications, and powerful diagnostics to monitor and protect not only the actuator but also the associated shut-off or control device, for example a butterfly valve or penstock. Actuator controls use time-stamped event logs to automatically store a multitude of operational and device data such as motor starts, run times, temperatures, vibration, torques, warnings and faults. This data provides a lifetime picture of the operating patterns of both the actuator and the shut-off or control device – a complete history of their mechanical, electrical and thermal life. It can help to predict when a valve or actuator will next need maintenance, and when to take remedial action in time to prevent unexpected downtime. Despite its obvious value, this information has in the past largely been restricted to special situations and to experts using specialist software. That situation is now changing. Cloud computing and the techniques of “big data” have made it easier for plant managers to extract actionable information from gigabytes of log files.

Empowering the hydropower plant manager
With its AUMA Cloud, actuator manufacturer AUMA provides a powerful platform allowing managers of hydropower plants to gain in-depth insight into the status and condition of their actuators and valves. Facilitating efficient asset management, the AUMA Cloud helps to save money and cut plant downtime. Any plant manager can benefit directly from this new tool, free of charge and with virtually zero setup. Only a few simple steps are necessary to read out the device and diagnostic data stored in the actuator controls and upload them to the AUMA Cloud.
Thanks to built-in intelligence, the log data is analysed and evaluated within the AUMA Cloud. Performance indicators such as uptime, number of motor starts and the most frequent faults are calculated automatically, allowing the plant manager to detect excessive loads or potential maintenance requirements at an early stage and take remedial action in time to prevent unexpected failures. The AUMA Cloud thus helps to minimize premature wear and extend the lifetime of actuators and valves, prolonging the plant’s life. Asset management is simplified, since it takes only a few steps to set up a digital overview of all the actuators and valves in a hydropower plant. The AUMA Cloud stores all the necessary information, including serial number, product name and type, while additional information such as log files and photos can also be attached. Actuators can be grouped and assigned to individual parts of a site, making it easy to locate particular devices and monitor the condition of entire plant sections.
The AUMA Cloud also makes it easy for plant managers to get expert help when required: Service requests can be sent from within the AUMA Cloud to AUMA Service. Device information such as data and photos can be directly attached to the request to aid detailed analysis. Additional benefits include online access to all the device-specific documentation for each AUMA device. This comprises operating instructions, technical data sheets, wiring diagrams and order sheets. Tedious searching for printed documentation is no longer necessary.

Easy to use
Getting started with the AUMA Cloud is simple: As a web application the AUMA Cloud runs in a standard web browser, requiring no installation at the user’s desktop and no changes to the IT infrastructure or the control system. Each plant manager can immediately use the AUMA Cloud after simple registration. The basic version is free of charge, with extra functionality available at a cost. Users can upload their actuators’ diagnostic and operating data to the AUMA Cloud via the AUMA Assistant App, another free and easy-to-use tool. This app uses a secure Bluetooth connection to harvest data from actuators around the plant. This is a secure offline approach that takes into account concern about the security implications of having field devices with permanent data connections to the outside world. If desired, however, permanent connections to the AUMA Cloud with continuous access to actuator data are also possible.

Performance indicators enhance transparency
Actuator and valve data uploaded to the AUMA Cloud is automatically analysed by intelligent algorithms.  Performance indicators are calculated for each actuator and presented in ways that make immediate sense to plant managers and maintenance engineers. Uptime is the most important indicator. By checking the uptime values, plant managers can see at a glance whether everything is fine, or if a deeper analysis or action are required. Other useful performance indicators include the total number of motor starts, the average torque, and the maximum temperatures experienced. The AUMA Cloud also calculates the average motor operating mode – important for confirming that an actuator is correctly specified – and shows the most frequent faults. The detailed view of actuator performance allows plant managers to detect excessive loads or maintenance requirements of individual actuators at an early stage. If a device shows problems, analysis via the AUMA Cloud also helps with troubleshooting, thus speeding up repairs. This is illustrated in the examples below.

Example 1: Correcting limit switch settings
A plant manager in Sweden contacted AUMA Service when an actuator showed an uptime of only 91 percent shortly after installation. A detailed analysis in the AUMA Cloud revealed that torque faults occurred frequently when the valve was approaching its closed position. Torque faults are particularly critical since excessive torque may reduce the lifetime of both actuator and valve. Possible reasons for torque faults include incorrect actuator sizing or faulty setting of the limit switches. In this example it was the latter. Armed with this knowledge, the customer solved the problem easily by adjusting the limit switching for the closed position, so that the actuator now stops earlier during the valve travel. Thanks to data analysis in the AUMA Cloud the plant manager was thus able to detect incorrect actuator configuration and prevent premature wear of both actuator and valve, while increasing plant availability.

Example 2: Optimizing control parameters
The AUMA Cloud also proved beneficial to a customer in France who contacted AUMA Service when an actuator motor was found to be overheating frequently. Uploading the data log file from the actuator and subsequent analysis in the AUMA Cloud revealed an uptime of only 71 percent, and 912 “thermal faults” in just a few weeks. Troubleshooting was facilitated by a performance indicator calculated by the AUMA Cloud: the average motor operating mode. In this case the actuator was found to be operating in the “intermittent duty” regime (S4) with an average duty cycle of 50 percent. A look at the order sheet – easily accessible via the AUMA Cloud – revealed that the actuator was designed for the S4 regime but with a 25 percent duty cycle. With significantly less idle time available for cooling, it’s no surprise that the actuator was overheating. AUMA Service thus recommended checking the control parameters for the setpoint control. By adjusting settings in the plant’s control system, the customer could reduce the number of actuator movements without compromising process accuracy.
Another check two months later showed 99 percent uptime and an average motor operating mode in the “short time duty” (S2) range, corresponding to a run time of just 6 minutes per hour.

Expert networking
In situations that need expert help, for example when a maintenance engineer requires spare parts or replacement actuators, or is uncertain about whether a particular data trend is cause for concern, the AUMA Cloud provides a quick and direct link to the manufacturer’s service organization. Plant personnel can send service requests, operating data, photos and other supporting documents via the AUMA Cloud. An AUMA expert can get on the job straight away and suggest a remedy, request more information, or arrange a visit from an engineer in AUMA’s worldwide service network. Each service request, message and file attachment is documented in the AUMA Cloud, so the plant operator can always see the status of all their current and past requests. In addition, keeping all the technical information in the AUMA Cloud means that nothing gets lost, so the time spent dealing with service issues is minimized.

Potential for the future
Experience shows that compared with other tools the AUMA Cloud provides plant operators with unprecedented transparency when it comes to the condition of actuators. The combination of a clear overview of plant assets plus straightforward and up-to-date performance indicators allows plant managers to identify problems early on, troubleshoot more easily, and introduce appropriate maintenance strategies. Even though AUMA actuators are robust devices designed for long service lives and requiring little maintenance, a regular check of the performance indicators by collecting and uploading actuator data to the AUMA Cloud can ensure that plant availability remains high. Doing this shortly after commissioning also makes sure that the new actuators are set up correctly and that processes are running at their optimum. Maintenance strategies can include regular physical inspection of actuators, accompanied by data collection for upload to the AUMA Cloud; optimization of spares inventory; and any specific measures needed to ensure plant availability. True condition-based, predictive maintenance becomes possible. For managers of hydropower plants, the AUMA Cloud provides an easy-to-use self-service tool. At the same time, it makes it easy to get expert help from the manufacturer’s experienced service engineers when required. Digital services such as the AUMA Cloud can be combined with conventional on-site services. For example, plant operators can carry out asset management and data collection themselves or, if they are short on personnel, they can delegate this to AUMA Service, either as an individual service task or within the framework of a maintenance agreement. For the future, cloud-based solutions offer enormous potential to take digitalization even further, enhancing automation and improving process efficiency. The future IIoT for electric actuators may encompass devices that continuously send live data into the cloud, which in turn will detect maintenance issues automatically and order service visits or the appropriate spare parts. AUMA is continuing to invest in enhancing these technologies and developing tailored solutions in close cooperation with plant managers.

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