Product manual

B Protocols TAC Xenta Server – Gateway, Technical Manual
150 (184) Schneider Electric Buildings AB, June 2011
04-00124-06-en
B.4.3 BACnet Object I/O Signals
Each BACnet IP device represents a specific group of I/O signals within
a server device. The device editor is used to create new pseudo device
types, or to modify existing types, as shown in the following screenshot.
Each signal can be used to read or write the present value a BACnet
object within any device signal groups of the type being defined.
• BACnet Type – Selects the type of the required BACnet object
(AI, AV, BI and BV are shown in the above example). The selected
type must match that of the underlying BACnet object (AI for an
Analogue Input, BV for a Binary Value and so on).
• Object Instance# – Sets the object identifier or instance number
of the required BACnet object. Normally this will be provided in
the documentation for the target device. Instance numbers can
range from 0 to 65565.
• I/O Signal Direction – Most BACnet device signals are used to
monitor an object’s present value, in which case the I/O column
parameter should be set to Read-only (R). In a few cases it may be
necessary to control an object’s present value, in which case I/O
should be set to Write-only (W).
Setting an object’s present-value signal to Read/Write (R/W)
allows both monitoring of its value as well as control of it. How-