Hi ,
please check the below links.
http://scn.sap.com/docs/DOC-35805 - SAP PI 7.3 – Monitoring Guide (Single Stack)
http://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/104677d9-fc8c-2e10-dc92-c4e660b0dd8c?overridelayout=true - Central PI monitoring and alerting
Regards
srinivas