Dräger REGARD 39 0 Series Instructions For Use Manual page 72

Operation
LED
Active
6.3 Power and inhibit LEDs
The power supply to the control unit is made via an AC or DC power source, or
both. If both are used, the DC power source (usually a battery system) acts as an
emergency power supply if the AC power supply fails.
Power AC LED
If the control unit uses both AC and DC sources, the connection of this LED is
optional. If the LED is connected, it lights up when the control unit is supplied via
the (primary) AC power source. The LED is off when the control unit is supplied via
the (supporting) DC power source.
Power DC LED
The LED lights up when the internal modules are supplied with a 24 V DC power
supply. (Irrespective of the power supply to the control unit, the internal control
modules require a 24 V DC supply.)
Inhibit LED
This LED lighting up indicates that the alarms are locked and therefore the
functions of the normal gas value monitoring and warning functions of the control
unit are inactive. If the LED lights up, the active LEDs flash and the internal acoustic
alarm sounder beeps every 30 seconds. External warning devices that are
configured for activation with locked alarms would also be activated.
The alarms are locked when the internal inhibit switch is moved to the maintenance
position: This is usually the case during maintenance and repair work on the control
unit.
6.4 Internal acoustic alarm sounder
The internal acoustic alarm sounder emits an acoustic warning signal if A1, A2, A3
or F1 is activated (not if F2 is activated). The acoustic alarm sounder beeps every
30 seconds when alarms are locked.
● Press Acknowledge/OK (or if available, carry out a remote acknowledgement)
to mute the acoustic alarm sounder.
6.5 External warning devices
The external warning devices used together with the REGARD
are activated via relays in the control unit and are configured according to the
individual requirements of the gas detection.
Condition
Flashes Channel active
Lights up Alarm lock
Off Channel inactive
®
3900 control units
®
REGARD 3900