Solution:

AO channels of ADAM-5024 should work well in general, but it is possible to break down under some situations, especially harsh environment. Actually, when you select current mode for your ADAM-5024 and connect it to another device for a long distance, the noise or abnormal spike could enter ADAM-5024 via cable, it could even damage some chips so that the AO function is gone (According to our test, 1KV is ok, but not for 2KV). In this case, you'd better add TVS (Surge Protector, 10-15V) between Iout+ and Iout- to prevent noise interference, you also can adopt the wiring cable with shielding to improve it.