VESDA PC Link HLI Access Protocol

Where the interface carries primary reporting rather than the secondary monitoring role it is recommended for, a condition applies: it must be integrated with the fire panel or primary reporting system it serves and approved or listed with that system, under the fire standards and codes that apply.

VHX-0320 is the VESDA Access HLI Standard, an interface that integrates VESDAnet networks with host monitoring platforms such as Fire Alarm Control Panels (FACPs) and Building Management Systems (BMSs). A VESDAnet socket interface is required to connect the HLI onto the VESDAnet network.

The Access HLI acts as a proxy for all VESDA devices on the VESDAnet network, providing access to the rich status information available from VESDA detectors as well as the ability to control and configure these devices. It is able to support up to 100 VESDA detectors on a single VESDAnet network, and consumes 1.68 W (Quiescent).

Beyond simple polling, a subscription mechanism allows the host to be asynchronously notified of changes in the status of the monitored VESDA devices, so the host is told whenever the state of a device changes, such as an alarm or fault condition being raised. Alarms reach the host within a few seconds of a detector reaching an alarm condition, with exact performance dependent on the polling strategy and size of the monitored network. A VESDA HLI is recommended to sit in a secondary monitoring role, watching fire alarms and other VESDAnet notifications, and it is also suitable for primary reporting - a duty it may take on only when integrated into, and approved or listed with, the fire panel or primary reporting system it serves, under the applicable fire standards and codes.