https://wiki.mikrotik.com/wiki/Manual%3APoE-Out
MikroTik supported PoE-Out standards
IEEE Standards 802.3af/at - Also called PoE Type 1/PoE+ Type 2, are PoE standards Defined by the IEEE. The aim of these standards is to reduce incompatibility between vendors. MikroTik PSE with af/at support is capable of powering both a Type 1 and a Type 2 PD. Valid PD should have PoE-In resistance from 23.75kΩ to 26.25kΩ. MikroTik devices which support af/at standard can also switch to Passive PoE-Out mode. (e.g. hEX PoE, CRS112-8P-4S-IN, CRS328-24P-4S+RM.)
Each PoE-Out implementation supports overload and short-circuit is detection.
https://mikrotik.com/product/RB3011UiAS-RM
Data from the section Powering:
Details
PoE in.............................................................................. Passive PoE
PoE out............................................................................ Passive PoE
PoE in input Voltage......................................................... 10-30 V
Number of DC inputs........................................................ 2 (DC jack, PoE-IN)
DC jack input Voltage....................................................... 10-30 V
Max out per port output (input > 30 V)............................. 0 mA
Max out per port output (input < 30 V)............................. 600 mA
Max total out (A)............................................................... 600 mA
Max power consumption................................................... 10
Max power consumption without attachments................... 10W
Conversion of value the amperage 600 mA = 0.6А
This problem occurs if the load current exceeds 0.6A, when the electronic power switch is switched on prematurely on the PoE-out.
Exceeding the current strength in 0.6A is possible, provided that there is a low voltage in the circuit at the output of the PoE.
POE PSE CONTROLLER is responsible for monitoring the switching on and off of the voltage for conducting measurementsof load status parameters... PoE-Out.
In the model RB3011UiAS there is a flaw in the algorithms for protecting power electronic components in the implementation of the POE-out in the event of a sudden drop in the magnitude of the voltage with a sharp rise to a normal operating value of 24V at presence of a residual voltage with an external device connected using PoE as a power supply.
The reason for the subsequent failure of the PoE-out at port Ether 10 when operating the RB3011UiAS equipment is the lack of protection algorithm in the POE PSE CONTROLLER
Is not excluded the option associated with the hardware algorithm of the block operation associated with the processes of opening and closing the semiconductor switch responsible for supplying the voltage for the PoE-out.
Where, when switching to the power-off mode, the PoE-out should be operated by an electronic circuit to suppress the residual voltage at the output.
In the case where the operating voltage is 24V
At the moment of transition to the RB3011UiAS reboot mode, it takes several seconds. In the time interval between the modes of transition to the reboot mode and the loading of the kernel of the operating system with the subsequent activation of the normal operating mode of power supply to the PoE output, it takes several seconds.Sometimes the load time increases, if the kernel operating system update procedure is started.
In the interval of time between these processes, the power supply is cut off to the PoE-out port, then, when the system is successfully started, the voltage is applied to the port with the PoE-out.
Before the power supply is applied to the PoE-out of RB3011UiAS, the remaining unused voltage can be stored on another device connected via the PoE device.
When the voltage is first applied to the PoE-out port from the RB3011UiAS, the amount of the inrush current that can exceed more than 0.6A is increased, at which time the overvoltage protection algorithm may not work due to a short period of time in a few milliseconds. What causes the failure of the power scheme for supplying voltage to the PoE-out port in RB3011UiAS.
