This is from the IM for the 7000 and 8000 (both same)
which is completely nonsensical bull. I would read it as a pullup to an internal +7.5V rail.
However another approach is to look at some compatible interfaces e.g. the Sandel SN3500
which shows the output is indeed a pullup to an internal rail. The resistors are needed in case a lamp fails, to make sure the output level is close to GND.
I suggest you put in those resistors if you are using those outputs for anything.
Re the avionics bus dimmer voltage, that will just be what the lamps need. On a 28V aircraft the bus will be something like 15V to 24V, with 15V for the lowest brightness setting. If they have half a brain however they won’t go to 24V but will limit it to about 22V which will make “24V” lamps last about 10x longer. Socata use 16V – 21V.
Hi guys,
Does anyone know where I’d find the standard for Marker Beacon output interface? DO-143 doesn’t specify it and PS Engineering appear to have 7.5vdc +/-4.5v. Is it a 7.5vdc, 5vdc or other DC output? If any bright spark (excuse pun!) has avionics dimmer voltage range too that would be great.
DMEarc