Uninterruptible power supplies reduce machine downtime

While UPS technologies are no longer optional in critical machine designs, engineers should still have options to select the best device for brownfield or greenfield applications.

By Eric Reiner June 2, 2020


Learning Objectives

  • Uninterruptible power supplies (UPS) are becoming more common in manufacturing.
  • Many machines need a UPS for uninterrupted data gathering in critical applications.
  • Choosing an UPS to match machine needs to local power reliability can help operations resume normally in the event of a shutdown.

Without unknowns in the design, commissioning and operation of machines, there would be little use for automation and controls engineers, who want to build reliable, dependable systems, despite environmental conditions.

However, unplanned downtime due to improper controller shutdown should not be one. Today’s uninterruptible power supply (UPS) technologies, which enable proper machine shutdowns and allow controllers to save projects and recipes when power failures or other issues occur, allow machine builders to plan for the unknown.

How UPS help machine applications

In the past, industrial UPS technologies were viewed as luxuries reserved for the most critical applications. Today, that view has changed as the number of machines that reliable, uninterrupted power has grown. Most contemporary machines collect and transmit data to measure performance, send alerts and complete track and trace for industries such as  pharmaceuticals, food processing, packaging and intralogistics.

In an e-commerce or distribution center application, for example, abrupt shutdown could cause a conveying, sortation or automatic storage and retrieval (ASRS) system to lose track of packages and products, leading to incorrect shipments and costly returns. It also could lead to corrupted files and programs on the machine controller, which would delay restart once power is restored.

Machine builder original equipment manufacturers (OEMs) know their facilities and the reliability of their electric utilities. Machines may be shipped to where the power reliability is unknown. Some areas regularly experience blackouts or rolling brownouts. Even if end user facilities have backup generators, the lag time between line voltage disappearing and the generator starting could be enough for disaster. With advances in capabilities, form factor and competitive costs, implementing UPS technologies for industrial PCs (IPCs), panel PCs and other machine controllers is no longer optional. However, there should still be flexible options to fit any machine requirements.

UPS capacities, connections deliver flexibility

Depending on the application, controller and other factors, many UPS options are available. Some PC-based controllers directly integrate a capacitive UPS for lower-end requirements. Options for 24 Vdc external capacitive and nickel-metal hydride (NiMH) battery-backed devices exist as well. These can include, for example, a 0.9 Wh capacitive UPS with a 120 W maximum power output, a 15 Wh battery-backed UPS with a 120 W maximum power output or even a 30 Wh battery-backed UPS with a 240 W maximum power output. Scalable options can provide power for seconds up to many minutes depending on application complexity and time required for controlled shutdown procedures.

Power delivery options also should offer flexibility. Some UPS devices connect to machine controllers via one-cable technology (OCT), USB 2.0 ports or input/output (I/O) terminals. OCT is optimal for PC-based controllers and touchscreens and combines the power supply and UPS communication in one cable, which benefits commissioning and maintenance. USB 2.0 is designed for all IPCs with an appropriate interface and a complete operating system. An I/O connection can enable use of these UPS devices with traditional programmable logic controllers (PLCs) and other devices. Regardless of vendor, they can read power failure signals and respond immediately. By offering maximum flexibility, the UPS also makes future controller upgrades easier if a new platform or additional features become necessary.

UPS form factor advantages

For maximum benefit, UPS technologies should offer compact, easy-to-integrate form factors. Simple installation via DIN rail or a mounting bracket enables integration of devices into new electrical cabinets in greenfield applications or flexible retrofits in existing brownfield applications. With compact sizes of 100 x 100 x 90 mm or less, the capacitive or battery versions meet tight footprint requirements.

For NiMH battery-backed versions, the battery cover should be accessible. All batteries eventually need replacement, and while UPS batteries are designed to last and provide maximum reliability, they are no exception. Selecting a device with a removable front cover will increase uptime, especially if it features only two screws. Through this design, the entire UPS will not need to be removed or taken apart for necessary maintenance, which means machine availability can remain as high as possible.

By selecting the correct UPS options for each application, machine builders and OEMs can be assured systems will shut down and start up again without issue. All systems, in general, should have a UPS because of the potential risks to system integrity, data acquisition and other tasks. Even if the price of reject product or improper shipments is minimal, the potential downtime resulting from improper shutdown could be quite expensive.

Whether its safeguarding a PLC running basic machine control logic or a panel PC providing a human-machine interface (HMI), cloud communication and more, UPS technologies allow today’s engineers to reduce risk.

Eric Reiner, IPC product manager, Beckhoff Automation LLC. Edited by Chris Vavra, associate editor, Control Engineering, CFE Media and Technology, cvavra@cfemedia.com.


Keywords: uninterruptible power supplies, UPS


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For more information: www.beckhoff.com/cu81xx

Author Bio: Eric Reiner, IPC Product Specialist, Beckhoff Automation.