The GATE GARD Limit Switch from Schneider Electric (Andover, MA) is designed to detect if press gates or machine doors are closed before a machine is allowed to cycle. According to the company, this solid-state, self-contained Square D-brand device detects the unique signature of its mating key. The passive key activates the switch without physical contact, allowing the key to approach from almost any angle. Switch to key alignment is non-critical. When properly aligned, the system allows up to a 0.25-in. key-to-switch gap.
With virtually no gap, a 0.20-in. offset is tolerated. Three LEDs (power, fault, load) indicate the switch’s operating status. Protective internal circuitry will lock the switch off under certain conditions, causing the fault LED to begin flashing. These conditions and the appropriate LED indication are given in the “LED Operation” table. When the fault LED is flashing, power must be reset to the switch to restore normal operation.
