TIME DELAY RELAY

摘要

A programmable solid state relay comprising: a relay base; an adaptor circuit; a configuration circuit; a trigger input; a voltage monitoring circuit monitoring the trigger input; a countdown timer; a microcontroller; and at least one switching circuits with first and second switching contacts, wherein: when the voltage of the trigger input exceeds a selectable trigger input threshold voltage, the countdown timer is loaded with a predetermined time value., the countdown timer is started and the at least one switching circuits are set to individually predetermined first states; and when the countdown timer has completed its countdown the at least one switching circuits are set to the complements of the first states. The relay performs self-checking of the switches and forces the switches to an open state upon detection of errors.