End-of-line capacitor for measuring wiring impedance of emergency notification circuits

摘要

A system includes a capacitor, a plurality of notification devices connected in parallel with the capacitor, and a controller. The controller is capable of determining capacitance of the capacitor during charge-up of the capacitor, and the controller is capable of determining the wiring impedance of the emergency notification circuit during discharge of the capacitor.

主权项

1. A system for measuring wiring impedance in an emergency notification circuit, the system comprising:
a capacitor; a plurality of notification devices connected in parallel with the capacitor; a reference resistor through which the capacitor may discharge; and a controller configured to determine the wiring impedance of the emergency notification circuit during discharge of the capacitor by monitoring voltage across the reference resistor; wherein the controller is further configured to determine an RC time constant based upon the monitored voltage across the reference resistor during discharge of the capacitor, where R is a sum of resistance of the reference resistor and the wiring impedance, and C is capacitance of the capacitor, the controller determining the wiring impedance of the emergency notification circuit in response to the RC time constant.