The IS 24F filter has been designed to protect security, fire, CCTV and door access systems from induced AC interference and voltage spikes. The most common cause of false alarms and system malfunctions is EMI (Electromagnetic Interference) also known as induced AC, this can be caused when high voltage cables are run close to low voltage cables.
To eliminate this problem the filter must be connected across the DC supply and to the control equipment earth. Any induced AC or voltage spikes will then be filtered to earth.
Testing for Induced AC:
Switch multimeter to the 20VAC range.
Measure the voltage between any DC +VE and earth.
The reading should not exceed 1.0VAC.
If the reading is greater than 1.0VAC this indicates induced AC is present.
The filter should be fitted with the RED lead to the DC +VE and the BLACK lead to the DC – VE and the GREEN lead to the control equipment EARTH.