I do not understand, why you want to use a m84 for an uncoupler? For an uncoupler you just need an short pulsed current.

A m84 is for a permanent current, either ot switch a lamp on/of or to toggel between 2 permanent currents, like using the m84 as a signal on hidden places.

See the pictures here on page 23 following

https://www.maerklin.de/...5_Digital_MM_2014_04.pdf

A m83 is for a pulsed current, like to switch a turnout or use an uncoupler.

The screen is a generic one for any Marklin accessory device with configurable outputs.

Most topically both the m83 AND m84. As such, not all options apply to every device.

The "Dimmer" is the amount of power the output provides , with values from 0 to 255(max = 100%)
For the m83 and something like LEDs attached, this equates to brightness
For the m84 where a relay is either on or off this value is ignored.

The "Mode" is actually semi-descriptive, however as with relays and the dimmer setting The m84 relay cannot MARS or perform the florescent light function. It can blink however.

The "Period"
This relates to modes that need a period or timmer value, e.g. a blinking function and is a value that is multiplied by
- 0.05 seconds for a m83 (a value of 20 , with a blinking mode means a blinking period of 1 second)
- 0.5 seconds for a m84

The "Switching Group" is
- not used for a m83
- for a m84 , a "binary mask" that identifies which OTHER outputs of the m84 to turn OFF when that output is turned on
This is how the "pairs" work out of the box, When the #1R relay is turned on the #1G realy (binary 2) is turned off.

if you wished you could use a m84 accross 8 fiddle yards (dead sections) so that when you activated a single port ALL other ports would turn off
e.g. changing the 2 against the #1Red to 254 would do this (254 being 2(1G)+4(2R)+8(2G)+16(3R)+32(3G)+64(4R)+128(4G))

The DR is for a german word that means Switch/Eneregise.
- checked=out stays on,
- unchecked means touch or output pulses.
In the case of pulsing, the on and off of the pules is dictated by you holding down the button on the controller AND whether the controller has a delay before it lets the m84 know you have lifted your finger.

I don't understand it either. The m83 is cheaper and it is the recommended way.

But I am interested in knowing how it could work with the m84. Can it automatically turn the uncoupler off again so you don't burn the coil?

I discovered from my experimenting that changing Outputs 1.3.5. &7 to "Switching", Period to 1 and leaving the rest at factory settings produces a short pulse at the four red terminals. Now if it also returned the track board knife switch representation back to closed instead of open it would be ideal but I can live with having to close it manually instead of having to hurry and turn it off to stop the irritating noise. Works great.
Supposedly there is a way to make both the red and green terminals independently operable by changing CV 79 but that is the next project. That would give me the ability to operate my four uncoupler tracks from two sets of connections freeing up the rest to play around with automatic train operation using sensor tracks.

Finally managed to make the m84 do pretty much what I wanted. I can operate the uncoupler track by clicking on the uncoupler track symbol in the track layout and it sends a short pulse so that I do not have to turn it off to keep from burning out the solenoid with no other action required before doing it a second time. Also I will be using the red and green connections to each operate an uncoupler thus freeing up most of the m84 for other uses.

I have a CS3+ and believe that unless you also have one what my screens show will do you no good. Also, what I discovered was that the options accessible on the m84 are dependent on what you are trying to operate. Once you select turntable you limit your choices. But first of all do you have a CS3+?

Output 1 appears to control the first red terminal. By changing the "Mode" to "Switching" and the "Period" to "1" should result in an approximately one second burst at position 1. Or you can do the same thing with the Outputs 2,3,4 and get the same effect at any of the four red terminals. There should be a way to do that for all eight outputs (4 reds and 4 greens) but that would mean playing around a bit, possibly changing the switching group numbers. For your information I solved my problem by ending up with a completely different screen when I did not select "multidecoder" on the earlier screen. Not sure right now which I did select but try different options. Right now I am reluctant to go back and play around with the screen as it does exactly what I want the way it is.