User's Manual
42
4.3 Connecting to Alarm Input and Output
Please read the followings before connecting.
Alarm input
●
Make sure alarm input mode is grounding alarm input.
●
Grounding signal is needed for alarm input.
●
Alarm input needs the low level voltage signal.
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Alarm input mode can be either NC (Normally Closed) or NO (Normally Open).
●
When you are connecting two DVRs or you are connecting one DVR and one other device, use a
relay to separate them.
Alarm output
The alarm output port should not be connected to high power load directly (It shall be less than 1A)
to avoid high current which might result in relay damage. Use the contactor to realize the
connection between the alarm output port and the load. The next device connected to the port
must meet the fire enclosure requirements.
How to connect PTZ decoder
●
Ensure the decoder has the same grounding with DVR; otherwise the PTZ might not be
controlled. Shielded twisted wire is recommended and the shielded layer is used to connect to
the grounding.
●
Avoid high voltage. Ensure proper wiring and some thunder protection measures.
●
For too long signal wires, 120 Ω should be parallel connected between A, B lines on the far end to
reduce reflection and guarantee the signal quality.
●
"485 A, B" of DVR cannot parallel connect with "485 port" of other device.
●
The voltage between of A, B lines of the decoder should be less than 5 V.
Make sure the front-end device has soundly earthed
Improper grounding might result in chip damage.
4.3.1 Introducing Alarm Port
The alarm input ports are dependent on the model you purchased.
Figure 4-2 Alarm ports
Summary of Contents for DH-XVR Series
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