Sentinel (BW)

Sentinel is the name of the Axalon's automated defense system. It was developed by Rhinox in the episode "A Better Mousetrap", and proved to be extraodinarily effective. To put it simply, most battles near the Maximal Base ended by someone activating Sentinel.

The Sentinel System itself consisted of an extremely powerful energy shield, and the simultaneous activation of every weapon attached to the Axalon. Despite its power, the shield can be disabled under unusually heavy fire.

After the Axalon was destroyed, the Maximals tried to retrieve Sentinel's CPU from the wreckage. Despite their efforts, they failed and it wound up in Megatron's clutches. Given the need for the Maximals to focus on defense of the Ark, this forced the Maximals into an almost entirely defensive footing for the rest of the war.

From Teletraan I: The Transformers Wiki, a Wikia wiki.