What’s the problem regarding current inrush protection In PLCs?
Conventional surge and noise protection for industrial PLC’s are not designed for the current inrush specifications of switch-mode power supplies commonly used in PLC applications. Accordingly, when the PLC is turned on and it operates over its internal cycle, current up to one and one-half times rated levels flow into the system. This can cause memory losses, data transposition and other problems. Marelco has solved this problem with its patented PLC Protector system. This is a high quality constant voltage transformer (specifically designed for current inrush of switch-mode power supplies) and packaged in an industrial quality enclosure. Additionally, MOVs and zener diodes may be added for extra protection at a nominal extra cost. A wide variety of optional switches, receptacles, wiring and cabinet choices are also available. The key to the system is the capacity of the transformer which is designed to be 1 1/2 times the rated capacity, to provide ample reserve for current inrush.
