Engineering Documentation

Chapter 4 – Equipment Controllers
BACnet DXR2 Room Automation Station
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Pressurized Rooms with Fume Hoods (Ethernet)
For Critical Environment DXRs in a pressurized space:
● The DXR2.E controllers may be in a star configuration, a daisy chain configuration
or a daisy chain with loop back and RSTP.
– The daisy chain may include up to 20 devices (room or fume hood).
● All controllers in a pressurized space must be on a common switch.
● Multiple pressurized spaces can be in the daisy chain and on the same switch.
● If doing RSTP, loop back to the same switch. The standard DXR documentation
shows the loop back with different switches.
● A single pressurized space may include up to 20 Fume Hoods (1 exhaust each),
and should not exceed 16 supply and extracts.
NOTE: DXR2.C handles 1 supply and 1 extract. DXR2.CX handles 2 supplies and
2 extracts.
● The controller running the room HVAC coordination application should be a C (1
room segment) when more than two supply/extract tracking pair and 8 fume hoods
are in the pressurized space.
Lab DXR2 Networking Examples
Fig. 78: Lab DXR2 network - Daisy chain