There is a minimum distance. Best way to use artillery is to hook it up with the SOM (Secondary Operations Module) which draws min/max ranging bars on the map when you are requesting fire missions. Even if you want to manage your artillery manually, using this system during testing can give you a better idea of what ranges will work.
You can find out the ranges during a mission using:
_min = batteryLogic getVariable "ARTY_MIN_RANGE";
_max = batteryLogic getVariable "ARTY_MAX_RANGE";
Since the artillery module just ignores you if a fire mission is requested outside acceptable ranges, it probably helps to always check that the range you want to use is OK before asking the module to run it for you.