Hello,
Is it possible to connect both an AC and a DC input at the same time? Can it be switched automatic to DC power in the event of an AC power outage? Thanks.
Yes.
The issue (or non issue) is that usually (cannot say specifically the 1100, but I see no reason why it should be different) Mikrotik devices like higher voltage, i.e. when connected on different connectors with (say) 24V and 48V they will draw power from the 48V one.
Since the internal (dual) power supply unit delivers 24V, if you provide higher than 24V on either the PoE or the DC connector it will use the latter.
And if you provide “exactly” 24V the circuits may be confused by fluctuations and “flap” between the two power sources.
So if you want the DC to be used only in emergency you will have to provide lower than 24 V power on the DC input:
http://forum.mikrotik.com/t/if-poe-in-dc-power-supply-connected-redundant-power/91996/1
A 20V power supply (as an example one of those used to power laptops) might be the right choice for your case, the total power draw should be around (in practice lower than) 25 W, so any such adapter would do.
Hi,
You can use something like LRS-35-24 and lower the output voltage to the minimum (21.6V):
https://www.meanwell.com/webapp/product/search.aspx?prod=LRS-35
or something similar.
Many thanks guys for advice, I will try it.