VDOT-ASD-400 Aspiration Detector
Velocity Detection
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VDOT-ASD-400 Aspirating Smoke Detector User’s Manual V1
condition can then be monitored by a fire alarm system when its fault relay is connected the
fire alarm system input module.
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Sensitivity Change: Sensitivity Mode 1, Sensitivity Mode 2
In some applications, the detection area environment background smoke level is different in a
day. For example, in work hours the background smoke level is usually higher than the non-
working hours. Sometimes, outside pollutants go into the detection area can generate false
alarm. There are needs to decrease the sensitivity to prevent the false alarm or increase the
sensitivity to provide better protection in a daily basis or in certain situations. In this case, the
GPI can be connected to a button, a timer, a PLC or even a relay output of other ASD detector
sensing the pollutant level from outside, so that that sensitivity adjustment can be made
manually or locally.
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User Defined Device Monitoring: UDI-1, UDI-2, UDI-3, UDI-4, UDI-5
The UDI, User Defined Input is usually used to monitor the status (relay) of other detection device,
like gas sensors, temperature sensors, or other aspirating smoke detectors.
The GPI-1 on the VDOT-ASD-400 termination board is a monitored contact with a 10KΩ terminal
resistor connected at the factory. When the GPI-1 is used, the terminal resistor needs to be moved
to the end of the line. When the line connected to the GPI-1 is shorted, the device reports a GPI-1
alarm; when the line connected to the GPI-1 is open, the device reports a GPI-1 fault.
The GPI-2 on the VDOT-ASD-400 terminal board is an active input with monitoring contact, and is
disabled by default. To enable the GPI-2, mount both the P1 and P2 jumper selection to 2/3 PIN and
set the corresponding GPI function. When the external active input is disconnected for less than 3
seconds, the corresponding GPI-2 function is activated, and when the GPI-2 connection line is
disconnected or open for more than 6 seconds, the GPI-2 fault is reported.
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RS-485
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Two RS-485 Terminals
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Built in RS-485 repeater, the cable length can be extended to next device for another
1.2km.
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RS-485 Network can be configured in closed loop for better communication reliability. The
communication can switch direction to communicate with devices behind the failure point
when there’s device failure, line break or line short circuit.
