A power supply monitoring system connectable to a power supply system for a system panel for controlling a building management system, the power supply monitoring system comprising: a bandpass filter for filtering a voltage across a capacitor of the power supply system , wherein the bandpass filter produces a filtered ripple signal from the capacitor voltage; a rectifier and transient filter that receives the filtered ripple signal and outputs a rectified ripple signal, which is an analog DC signal representing a level of ripple of the voltage across the capacitor; and a controller configured to perform a comparison of the rectified ripple signal to one or more acceptable threshold values for the rectified ripple voltage and report a health of the power supply system to the system panel responsive to the comparison, wherein a microprocessor is configured to operate as the controller, wherein the microprocessor; receives the rectified ripple signal via an Analog to Digital, ADC, port of the microprocessor, converts, via the ADC port, the rectified ripple signal into a sampled rectified ripple signal, and sends, via a long term trend reporter module included in the microprocessor, the sampled rectified ripple signal to the system panel on a periodic basis and/or when the sampled rectified ripple signal has changed in value, compares, via a fault threshold detection module included in the microprocessor, the sampled rectified ripple signal to one or more acceptable/allowed threshold values for ripple voltage, and produces a health signal in response to the comparison indicating whether the level of ripple of the capacitor voltage meets one or more acceptable/allowed threshold values, and sends the health signal to the system panel . a bandpass filter for filtering a voltage across a capacitor of the power supply system , wherein the bandpass filter produces a filtered ripple signal from the capacitor voltage; a rectifier and transient filter that receives the filtered ripple signal and outputs a rectified ripple signal, which is an analog DC signal representing a level of ripple of the voltage across the capacitor; and a controller configured to perform a comparison of the rectified ripple signal to one or more acceptable threshold values for the rectified ripple voltage and report a health of the power supply system to the system panel responsive to the comparison, wherein a microprocessor is configured to operate as the controller, wherein the microprocessor; receives the rectified ripple signal via an Analog to Digital, ADC, port of the microprocessor, converts, via the ADC port, the rectified ripple signal into a sampled rectified ripple signal, and sends, via a long term trend reporter module included in the microprocessor, the sampled rectified ripple signal to the system panel on a periodic basis and/or when the sampled rectified ripple signal has changed in value, compares, via a fault threshold detection module included in the microprocessor, the sampled rectified ripple signal to one or more acceptable/allowed threshold values for ripple voltage, and produces a health signal in response to the comparison indicating whether the level of ripple of the capacitor voltage meets one or more acceptable/allowed threshold values, and sends the health signal to the system panel . <EOS>