This guide provides detailed information on securing advanced controllers within a building automation system (BAS). It outlines various elements related to security, including system accounts, account verification codes, and the protection of devices from unauthorized access. The document explains the significance of robust local security measures and provides insight into securing the Niagara operating system. Additionally, it discusses general good practices for firewall settings, virus protection, and intrusion protection. The guide also covers the General Data Protection Regulation (GDPR) and secure communication protocols. Key aspects of network planning and installation are detailed, including recommended configurations for BACnet networks. It emphasizes the importance of documenting physical devices and interactions with external systems to ensure comprehensive security. Moreover, the guide addresses the need for user password management and offers recommendations for configuring advanced plant controllers.