How to accurately identify the source of PoE errors and minimize PoE troubleshooting time? This article will detail three common PoE faults and troubleshooting methods for Power over Ethernet.

PoE Error 1: The PoE switch does not supply power

PoE PD failure to start is one of the most common errors in PoE failures, usually caused by PoE component problems or incorrect configuration commands. Follow these steps to resolve the problem:

Step 1: Check the PoE IEEE standard and the power supply modes of PSE and PD

If your PoE network switch and PD do not have quality issues, you need to confirm that both PSE and PD comply with PoE IEEE standards. Note that a non-standard PoE switch, also known as a passive PoE switch, is always powered over an Ethernet line at a specific voltage, regardless of whether the end device supports PoE. If not fully prepared, the passive PoE switch may burn the terminal device. In addition, the power supply mode of PSE and PD is also a factor that may lead to PoE failure. There are three PoE modes: Alternative A, alternative B, and 4-pair transmission. If PD only supports PoE mode B power supply, and the PoE switch is based on Alternative A, then PD and PoE switch cannot work together. Be sure to confirm the PSE and PD power supply mode with your supplier.

Step 2: Check PoE cabling

Mismatch between the Ethernet cable and the PoE port may cause network faults. In addition, PoE failures may occur if the cable has a hardware failure or does not meet the necessary standards. Therefore, it is highly recommended to ensure that the Ethernet cable supports PoE and is available before connecting to the receiving device.

Step 3: Check whether the PoE power supply is sufficient

In theory, the PSE device interface can automatically detect PD when PD is connected. If the power is low, PD will not be able to supply power. Ensure that the power running PD does not exceed the power budget of the PoE network switch. If the PSE detects that the power level of the PD is within its capacity range, it will power the PD.

Step 4: Check the PoE power management configuration

Check whether automatic PoE power management is configured for ports on the switch. If not, you will need to manually power the PD connected to the PoE network switch interface.

PoE Error 2: PoE PD is powered off or reloaded intermittently

What if the working PD stops powering or reloads intermittently? The phenomenon of reinstallation or operation interruption may be caused by insufficient power supply and poor PoE cable quality.

Step 1: Check whether the PoE power supply is sufficient

When the PSE output power is not enough to meet all the PDS running at full power consumption, the PoE PD may intermittently power off or reload, resulting in the inability of the PoE switch to power. Take network cameras, for example. When testing all the extended functions such as pan, tilt, zoom, heater, wiper, etc., PD may consume more power during testing than is required for normal operation. If there is no if there is no additional power supply, the camera may fall into continuous startup cycles. To troubleshoot this PoE, measure how much power the network camera needs during startup and use the correct PSE to provide enough power.

Step 2: Check PoE cabling

If the Ethernet cable used in the PoE link is more than 100 meters, or there is a power outage due to the material and resistance of the cable itself, the PD will not be able to get enough power, resulting in problems such as network failures or delays. If the cable is unqualified, the PoE may fail.

PoE Error 3: Some PDS are being powered on while others on the same PSE are not

If there is a certain amount of PD that can be powered on, while other PDS are still powered off, you should follow the following tips to check:

Step 1: Check whether other ports have available PD

Check whether some PSE ports are faulty. Disconnect the PoE cable between the Ethernet switch port and the PD that cannot supply power. If the PD can still supply power after connecting to other PoE ports, some ports are faulty. Use the configuration command to verify that the port is closed or incorrectly disabled. If yes, run commands to enable the PoE function.

Step 2: Check the PoE power

If a new PD is added to the PSE port and the PoE switch power budget is exhausted, PD will not be powered on. Ensure that the remaining PoE power of the PSE is equal to or greater than the maximum output power required by the connected PD. In addition, limit the current at each port to a safe level and use additional PSE devices if necessary.

PoE Error 4: The PoE camera is not powered on

If your camera does not turn on when using a PoE switch or PoE power supply, you can follow these tips to resolve the problem.

Step 1: Check whether the camera is compatible with the PoE switch /PoE feeder

Check what type of PoE switch or PoE power supply you can use for your camera. Ensure that the specifications of the PoE switch or PoE injector are correct.

Step 2: Check that the camera is fully connected to the PoE switch /PoE injector

Check the PoE port indicator on the PoE switch or PoE injector. If the indicator is not on, you can plug the camera into another port and try using another Ethernet cable. Ensure that the PoE port on the switch is not rusty or damaged. It can be proved by replacing other good PoE ports.

Step 3: Check whether the PoE module of the camera is powered on

If the PoE module cannot be powered, use a DC adapter with the correct output voltage to power the camera. Make sure the DC/AC adapter is available. In general, the adapter has an indicator light that can be used to determine whether power is being supplied. Some network cameras with DC/AC power ports support DC12V/2A and AC24V /3A power supplies. Ensure that the adapter specifications are consistent with those of the camera.