LED Driver Handles Industrial Power-Supply Indication (Download)
Industrial control systems universally employ 24 V DC for their field supply voltage. The presence/absence of power-supply voltage is commonly signaled by LEDs found on equipment like the controller head unit, as well as I/O and communication modules. LED supply lights aid in minimizing installation, maintenance, and downtime in industrial systems/subsystems such as programmable logic controllers (PLCs) and distributed control system (DCS) controllers, power-supply units, sensors, and actuators.
Supply LEDs should light up when defined conditions are met; for example, voltage being in the required operating supply range. Despite their conceptual simplicity, real implementations aren’t that trivial. They require voltage comparators with hysteresis, need to be self-powered, and must drive LEDs consistently.
