Project background

The road section management sub-center needs to gather the vehicle detectors, cameras and fan control signals of the six tunnels. The inverters and lighting rectifier equipment in the tunnels have strong interference, and the original Cable solution has serious image ripples.

Needs and Challenges

• The longest single cave is 3.4km, and cameras are densely distributed along the cave wall;
• Jet fan 485 control needs to be transmitted back on the same fiber as the video;
• The environment inside the cave is humid and the equipment protection level requirements are high.

Implementation points

Along the optical cable ring network on both sides of the tunnel, the cameras are grouped and connected to 4 channels of video + 1 channel of reverse 485 optical transceivers; the fan and lighting control are carried by 2 channels of bidirectional 485 data optical transceivers; rodent-proof armored jumpers are used for all leads from the tunnel wall; the branch center uses a 16-channel rack-mounted model for unified convergence and output to the large monitoring screen.

Deliverables

• All 118 channels of video are transmitted back clearly, with ripples and snowflake noise disappearing;
• The fan remote control success rate is 100% and passed the network acceptance;
• The equipment in the cave has a zero-fault replacement record for two years.