A site’s POE exchange (model S3328) connected to more than ten AP which model is WA60, after restart the POE switch when it is power down, some AP can run normally, and some can't work normally due to can’t power on.
1 In POE exchange, interchange the Ethernet port connected the normal AP and abnormal AP, found that the AP whose power supply is abnormal still can’t power on, can eliminate POE switch port fault.
2 Dismount the AP whose power supply is abnormal, get to POE exchange and local connect directly, AP can power on and operate normally, can eliminate the AP’s POE power receiving module problem.
3 View the distribution situation of AP again, found that the AP whose power supply is normal is very close with POE exchange, and the power supply abnormal AP has further distance with POE exchange, but also within 100m. Doubt line has a problem, but all AP has normal power supply before POE switch power down.
4 Trough contact POE exchange engineer confirmed: if the POE exchange in long distance power supply and no normal grounding, the POE detection weak current signal it send is easy susceptible to interference, therefore it is impossible to detect the existence of the far end equipment and unable to do power supply to AP. Open the forced power supply switch of the port in the switch, AP can be power on and can work normally.
1 The power supply of POE switch port fault;
2 The POE power receiving module of AP fault;
3 POE power supply circuit has a problem;
4 Other problems.
1 The length of POE power supply’s Ethernet line should be less than 100 meters.
2 The POE exchange connected AP required to open the forced power supply switch of the relevant port or connect ground, avoid the circumstance due to can’t detect AP lead to AP hasn’t power on.