Aux Power for B200S not supervised on Silent Knight 6000 series Fire Panel

Submitted by Todd H on Sat, 02/05/2022 - 14:03

When using System Sensor B200S Intelligent Sounder Bases with AUX power or constant power whereas the power source does not monitor the power circuit using an EOL resistor, removal of the AUX power from the sounder base loop does not activate a trouble or supervisory condition on the fire panel.


Unlike the Silent Knight 5000 series or Notifier series, the Silent Knight 6000 series does not have the ability to respond to the loss of Standby Power on sounder-base circuits. 

This information is available on the System Sensor B200S installation sheet.

I found two versions of the installation instructions for this product on the System Sensor website. Both are available below. The document from 2010 list some fire panels that have "SOUNDERBASE STANDBY POWER MONITORING" ability. The Silent Knight 6820 is not listed. The Document may precede the 6820.

The manual dated 2018, gives the same basic information but does not list which FACP models have sounder base standby power monitoring ability.

According to Silent Knight and field testing, I have found the 6820 does not respond with the removal of standby power from a sounder base aux power circuit.


Option 1:

Following the System Sensor B200S manual you will need to install a relay at the end of each AUX power circuit to monitor the standby power status. The Relay output must be NC and then held open when energized by the AUX power. Using a monitoring module connected to the COM and NC leads from the relay, the monitoring module will go into alarm on loss of AUX power.

You cannot use a traditional end-of-line power loss relay, commonly used in 4-wire smoke systems because those relays only have a NO output. 



Option 2:

Use a control module to distribute standby power to the AUX circuit. The control module would have to be activated through MAPPING when any sounder base on that circuit required power for notification operation. 

This option has the advantage of not requiring the extension of the AUX power circuit from the last device to a location where the installation of a relay and monitoring module are feasible.  However, it is more programming intensive and requires the installation of the control module between the AUX power supply and the 1st sounder base.


Option 3:

A more unconventional method is to install a control module at the AUX power end-of-line (extending the power circuit as needed).  Connect the AUX power to the control module POWER INPUT terminals and strap out the output side. If there is a loss of standby power, the control module would go into trouble. No Mapping would be required. 



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