When you click in the Bacnet Device Manager, a Configure Device Discovery dialog appears, as shown in Figure 15.
Depending on the size of the BACnet network you are learning, you may wish to configure settings from defaults. By default, all known networks are selected to learn (each network number matches an entry in the router table), “all networks” are not selected to learn, and the full range of device IDs (0 to 4194302) is specified.
All fields in the Configure Device Discovery dialog are explained, as follows:
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Device Low Limit
Devices with an instance ID lower than this are not discovered. Default value is 0.
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Device High Limit
Devices with an instance ID higher than this are not discovered. Default value is 4194302 (the maximum valid BACnet instance number).
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Network
Allows selection of either:
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All Networks — Niagara will search on all possible BACnet networks segments, including all locally connected networks, as well as segments accessed over BACnet routers.
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<Known networks (by network number)>— Choices reflect the number of network ports available under Bacnet Comm, Network component, plus any additional remote networks discovered by receiving “I-am-router” messages. Click to include/exclude as needed. By default, all known networks are individually pre-selected.
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Wait Response Time
Determines how many seconds Niagara waits before determining that all BACnet devices that exist have responded to the discovery request. The default value is 10 seconds.
Often, you may wish to further limit the range of device IDs, and perhaps enable the device learn across “All Networks.” In the case of MSTP networks, or complex BACnet networks (that span several routers, you may need to set the “Wait Response Time” upwards (from 10 seconds) in order to learn all BACnet Device objects.