That TP-LINK thingy is not a standard (which standard?, I love standards, there are so many of them 
) PoE device.
The PoE injector that comes with that is intended to be more than anything else an “extension cable” powered by the “normal” power supply that comes with the device (1A@12V).
It is already a good thing that the TP-LINK did not fry @24V.
If you want to power it from a RB3011 you need a splitter/converter, the kind often used for IP CAMs, BUT you probably want a GB capable splitter AND you want it compatible with the 24V passive Poe of the RB3011, which uses - like most Mikrotiks - Mode B. (it is not easy to find one of these, mainly because a good half of these product are vaguely documented or mis-documented).
I.e., as an example, this one is GB:
https://shop.poetexas.com/products/gaf-12v12w/
BUT it is 802.3af (48-56V AND NOT 24V)
This one is passive, mode B, 24V BUT ONLY 10/100 MB:
https://shop.poetexas.com/collections/splitters/products/poe-12v10w
See also:
http://forum.mikrotik.com/t/poe-compatibility-mikrotik-rb3011-ruijie-rg-rap6202-g/174190/1
It has to be seen if your device supports (it could or it could not) support 24V power, in which case you could use the Mikrotik
https://mikrotik.com/product/RBGPOE
that - although marketed as injector - should work also in reverse as splitter (with a male-male jack converter).
Otherwise you can still use the above but you will need an additional 24V to 12V converter.
PoE (actually the semi-random ways it has been implemented) is a mess. 