Explanation
Security policy schedulers are a feature that allows you to activate or deactivate a policy for a specified time period. You can create schedulers for a single or recurrent time slot, and apply them to one or more policies. A policy can only have one scheduler associated with it, but a scheduler can have multiple policies associated with it. When a scheduler is active, the policy is available for policy lookup. When a scheduler is inactive, the policy is unavailable for policy lookup. A policy without a defined scheduler will always be active, unless it is explicitly disabled. References:
Scheduling Security Policies
schedulers (Security Policies)
Security Policy Schedulers
scheduler (Security Policies)