Energy efficiency not the only game

With the power supply typically the largest processor of power in the cabinet, its efficiency is understandably an important factor.

"Low-efficiency power supplies translate to extra heat in a controls cabinet, which leads to larger cooling systems, which leads to more energy consumption," says Will Healy III, connectivity marketing manager at Balluff. "To fight this cyclic effect, engineers need to at least be aware of the efficiencies of the supplies they design into their control systems."

Efficiencies have improved. Most power supplies today have an efficiency rating above 90%, leaving little room for improvement, notes Ken Allwine, product marketing, Interface power solutions, Phoenix Contact. Some of the latest advances today are within the physical size and intelligence of the device.

"With America's aging infrastructure and the occasional blackouts/brownouts, the reliability of a location's power source can be questionable at times," Allwine says. "The more feedback the power supplies can provide, the more the user knows about the quality of their source." Advanced power supplies indicate overload conditions, battery backup status, and even when it's time to change the battery.

For an end user, knowing what is going on with his power supply can be critical to effective operation of the entire production line. Though often overlooked, workforce deployment is an important component of efficiency. "This is why we've integrated signal outputs and communication via serial interface — users get the efficiency of remote monitoring, ending routine in-the-field trips," says Michelle Goeman, product manager, terminal blocks and electronic interface for Wago. "It simplifies troubleshooting and can play a role in monitoring machine power consumption via I/O, which is helpful for asset management. This enhanced visibility ultimately prevents downtime, keeping overhead low."

Industrial manufacturing is also pushing to get devices out of the controls cabinet as much as possible, including power supplies, Healy says. "There is a developing need for rugged dc power supplies to be mounted on the machine outside the cabinet used to supply automation and controls equipment with power," he says. "This reduces the footprint of the controls cabinet and creates one less reason for maintenance to have to open the cabinet and be exposed to the dangers of arc-flash."