Baldwin Boxall Impedance Monitor (BVLAM)

Baldwin Boxall Impedance Monitor (BVLAM)

The BVLAM provides 8 zone 100V line relay switching loudspeaker zone selection from 1 amplifier.

It incorporates impedance monitoring on all 8 loudspeaker lines when the zone is not selected. If the load increases, (impedance decreases) the appropriate fault LED illuminates steady, and if the load decreases (impedance increases) the fault LED will flash.

The impedance changes for a fault to be detected is selected to either 20% or 40% using the mode DIL switch 8. If the impedance falls to approximately 50% of its original value the line is considered to be short circuit and will not be selected to the amplifier.

All 8 zone select inputs will access when it is between 2 to 6.5V. An open circuit, access input above 15V will be indicated by the appropriate fault LED flashing and a short circuit, access input below 2V by the fault LED illuminating steady.

Under all fault conditions the O/K LED will extinguish and the common fault relay volt-free contacts to change state.

Key Features

• Rack-mountable unit (1U high). Two units can be mounted across one rack ‘shelf’.
• Provides eight loudspeaker zone selection from one amplifier.
• On receipt of a signal from an input (ie zone selecting microphone) the BVLAM triggers the amplifier to output to the selected zone.
• An internal relay enables zone switching.
• The BVLAM provides constant impedance monitoring on each of the eight loudspeaker circuits when not selected.
• LEDs are used to indicate a drop (or increase) in impedance - set at either 20% or 40% by DIL switches.
• Note: due to detection accuracy, BVLAM is only suitable for BS5839-8 voice alarm systems with less than five speakers per circuit.
• Access faults on any of the zones from the microphone are indicated by LEDs on the BVLAM.
• Additional LED indicators are provided to show ‘system healthy’ and ‘supply healthy’.
• The Baldwin Boxall Impedance Monitor BVLAM provides a combination of zones/ relay switches from one amplifier. It changes if a fault is detected.