Welcome to the forum!
Your best bet is to use a simple script. The time honoured way of learning scripting is to study
snYpir's Friendly Intro to Code snippets
Johan Gustafsson's Scripting Tutorial
macguba's Tutorial Mission
Your script will be called from the init field of the unit you want to do the animation
[this] exec "looper.sqs"
and the script file called looper.sqs (make sure it is not looper.sqs.txt) will be something like this
; this script makes a loon repeat the animation
_loon = _this select 0
#loop
? not alive _loon : exit
? the stop condition is true : exit
_ loon playmove "EffectStandSalute"
~3
goto "loop"
That's not a working script, just a good sketch. You'll have to play with it a bit to get what you want.