when i shoot turret with pistol with 6 dmg full shield depletes after 1 shot (200 shield HP)
when biters attack they dont deal any damage to the shield and damage the turret directly

and please also add the shield value and recharge rate in info panel

i can't reproduce that, can you send me a screenshot of your settings?
make sure that you either have the setting "research enabled" on and the shields researched, of that setting off.
Also make sure you have the setting "Energy consumption" off, or the turrets under an electric pole with a network that provides enough power.
adding the shield parameters to the info panel is not possible since there is no api for that

my settings are:

max shield 200
recharge rate 1
penalty 5
passive consumption 0.1
consumption check
alternate graphic check
research activated check
multiplicator strenght 0.1 (should be 10% right?)
multiplicator recharge rate 0.1

i now researched shield strenght level 1 and recharge level 1 and and after a 6 dmg pistol shot shield losses 80% HP

Biters now occasionally oneshot shields but still also damage dircetly without affecting the shield hp.
i notice the shield effect is still online while spitters vomit is on tower. maybe it has to do something with that? other than that i do not understand why the HP is so weak

ah i see, you've set the multipliers to 0.1, which means that instead of 100 hp your shields will only have 10 hp and your charging rate will be 1/s instead of 10/s
(the "max shield 200" and "recharge rate 1" settings get ignored because you've enabled research)

aaa i see thanks. i now made multiplicator recharge 0.1 and 0.5 strenght. now it makes sense to me. the turret has now 50 HP with upgrade level 1