ZMODO ZMD-DT-SCN4 - Manual (Page 14)

H.264 Super Digital Video Recorder User Manual
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should be isolated by relay.
２、 Alarm output
Alarm output cannot be connected with high-power load (no more than 1A).When forming the output
loop it must prevent the big current from relay damage. Use the contact isolator when there is a
high-power load.
3、Front equipment grounding note
Bad grounding can lead to the burnout of the chip.
4、Alarm input type unlimited
The DVR alarm output port is constant opening type.
2.7.1 Alarm Input port explain
The grounding and the com port of the alarm sensor are parallel (The alarm sensor is external power
supply).
The grounding of the alarm and the DVR should be shared.
The NC port of the alarm sensor must be connected with the DVR alarm input port.
The grounding of the power supply and the alarm sensor must be shared when used in external
power supply.
2.7.2 Alarm Output port explain
Switch alarm output (normally open contact), external alarm device requires a power supply.
In order to avoid voltage overload and damage the host, attached please refer to relay parameter list,
see table 2.2.
Type：JRC-27F
silver Interface material
rating
(resistance load)
Rating switch capacity 30VDC 2A, 125VAC
maximal switch power 125VA 160W
maximal switch 250VAC, 220VDC
maximal switch current 1A
isolation Homo-polarity 1000VAC 1minute
Inhomo-polarity 1000VAC 1 minute
Interface and winding 1000VAC 1 minute
Surge voltage Homo-polarity 1500VAC (10×160us)
3ms max Turn-on time
3ms max Turn-off time
longevity mechanical 50×106 MIN（3Hz)
electric 200×103 MIN (0.5Hz)
-40~+70℃ Environment
Table 2.2 Parameter list