I am assuming this is an an Aruba Controller.
Unassociated users get the "ap ap-blacklist-time" parameter in seconds:
config t
ap ap-blacklist-time 600
Users that are associated to a Virtual AP get durations based on these blacklist parameters:
wlan virtual-ap <profile>
auth-failure-blacklist-time <seconds>
blacklist-time <seconds>
Type "show ap blacklist-clients" to see blacklisted clients and their times.