Why wireless bridges interfere more in elevators

Junior high school physics knowledge, electrostatic shielding.

Power, lighting, fan, control, communication and other cables are usually arranged in the elevator shaft, and all kinds of cables will produce electromagnetic radiation. In the same way as antenna reception, coaxial cable will also work"Receiving"These interferences, that is, the interference electromagnetic field produces interference induction current on the cable, and this interference induction current will also produce interference induced voltage (electromotive force) on the longitudinal resistance of the outer conductor (braided mesh) of the cable, which is just connected in series in the first signal transmission circuit"Long ground wire", forming interference.

What's more, these accompanying cables are parallel to the ** cables and bundled together in close proximity. This creates proximity"The best and most effective"Interference coupling relationship. In general engineering, the shielding interference method of wearing metal pipes or metal grooves can be adopted, but in the environment where the elevator follows up, this method is powerless.

Therefore, it is very difficult to resist interference in the elevator environment, and only better design and construction methods can be selected.

According to the various factors of interference, the interference signal can be suppressed from three aspects: suppressing the interference source, eliminating the coupling of the interference signal, and suppressing the interference in the working system.

1. Choose a cable with a small attenuation coefficient, good shielding performance and high tensile strength, which can improve its own anti-interference ability, reduce the attenuation, and prevent the interference signal from "invading" the interference from the cable shielding layer.

2. Reasonable wiring: Reasonable wiring can effectively avoid the interference signal from being "coupled" through the cable, minimize the parallel strapping distance with other cables, and keep the ** cable away from the interference source, so as to "avoid" interference.

The elevator is not allowed to install equipment unrelated to the elevator, and the elevator is now serial communication, which will interfere with the normal operation of the elevator.

It will interfere, it is recommended to choose a shielded wire

There may be interference, and it needs to be unobstructed in the middle.

We made 8 elevators in Tengzhou, Shandong, and the effect was very good, and the use was done.

Isolation can be set between wireless bridges, or binding.

Reduce the power, change the channel, and increase the link threshold.

This should be interference, the network delay caused by signal interference.

1. Replace the test terminal for comparative testing.

2. Step-by-step ping packet test, decompose the entire test into test terminal to base station, base station to gateway, gateway to external network, analyze and locate the cause of the fault after performing the step-by-step ping test, and solve the fault.

3. If the ping delay from the test terminal to the base station is too large and the packet is lost, try to adjust the base station channel, transmit power, and installation angle.

4. If the ping delay from the base station to the gateway is too large and the packet is lost, check the wired link from the base station to the gateway, focusing on the long network cable from the POE to the base station and the short network cable from the POE to the switch, and do not rule out the fault of individual optical fiber links.

5. The ping delay from the gateway to the external network side is too large, and the packet loss needs to be reported to the network operator to assist in troubleshooting. 6. There is also whether there is other equipment in the elevator and whether it is signal interference.

Wireless bridges are most afraid of encountering interference in use, and no matter what interference will greatly affect their signal strength and transmission distance. So avoiding distractions is a must. So what are some common interferences? How to avoid it?

Interference from wireless bridges generally includes two categories: external interference and internal interference. External interference refers to external obstacles, obstructions, etc., such as tall buildings, trees, etc.; Internal interference is generally between devices of the same kind, that is, between bridges.

1. External interference.

As mentioned above, there are many external interferences, such as buildings, trees, etc., especially the impact of buildings on wireless bridges is very large. During deployment and construction, it is necessary to avoid tall buildings as much as possible to ensure that there is no obstruction and visibility between the transmitter and receiver.

2. Interference from similar devices.

There is also more interference from similar devices, such as bridges of the same frequency, signal sources in the system, power supply, etc., in this case, you can adjust the frequency of the wireless device, choose a clean channel, or change the position of the transmitter or receiver of the wireless device, and widen the distance between the devices.

If there is packet loss, unstable picture, clutter, black streaks, ripples, etc., if there is interference, the device needs to be checked one by one to find the cause.

Not all devices have interference with wireless, such as mobile, Unicom signal towers, walkie-talkies, wireless**, etc., which have no impact on wireless microwave devices. In the case of interference sources, the frequency of the equipment can be adjusted, or the location can be installed far away from the interference source, so that the interference to the wireless microwave equipment is greatly reduced.

And the frequency is different, the general household equipment uses this frequency, the use is very ordinary, the wireless bridge channel is many, the anti-interference ability is strong, the wireless bridge is some with wireless relay function, the wireless bridge includes wireless relay. Wireless relay, in the non-visual situation, 1 point transmission 3 points can not be reached, can only find one in the middle of 1 and 3, 1 can be seen, and 3 points can be seen relay point, the device is a dual-mode wireless bridge to achieve the relay 1 to 3 points networking function.

If you don't want to be professional, you have to experience it in detail, and if you're professional, you can use a spectrum tester to find it out.

Depending on the number of wireless bridges, different bridges can be set to different channels to avoid interference, and if they are set to the same frequency, there will be same channel interference. There are only a few channels.

The wireless bridge for elevator monitoring is the best to use, which can effectively avoid interference.

One is installed at the bottom of the car and the other is installed in the pit, which belongs to line-of-sight communication, so there is no difficulty. Find a big manufacturer OK!