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4.4. BACnet Objects and Network Configuration
Transmission type
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Physical layer: EIA-485
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Protocol: BACnet MS/TP
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Baud rate: 9600-76800bps (38400bps default)
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MAC address: 1 (default)
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Device Instance: 100001
Initial Configuration
All configuration parameters are settable through use of the buttons on thermostat by entering the
Engineer Menu, or once installed on the BACnet network, configuration can also be altered using
BACnet commands. Network command-based configuration can also be accomplished using a
laptop/computer/tablet and Contemporary Controls’ free
MS/TP Communication Configuration
Overview
The BASstat MS/TP thermostat is preconfigured with a MAC address of 1 and default baud rate
of 38400bps. BACnet MS/TP configuration requires setting the baud rate or using the default
baud rate of 38.4kbps. A unique MS/TP MAC address is required to distinguish it from other
MS/TP devices on the bus (default MAC address = 1). When more than one BASstat is installed
at the same time, their MAC addresses must be configured prior to communicating on the
BACnet MS/TP bus or communication will fail due to duplicate MAC addresses. A unique Device
Instance Number throughout the entire BACnet internetwork is also required to distinguish the
device from all other BACnet devices.
End-of-Line Termination
The BASstat does not provide End-of-Line termination. If the BASstat is the first or last device on
the MS/TP bus, a termination resistor (120Ω) must be applied across pins 16 and 17 of the input
terminal.
Addressing
The MAC address can be set from Engineering Menu item (Addr) with values of 1 - 127. The
Baud rate can be set from Engineering Menu item (bAud) 9.6kbps – 76.8kbps.
A unique Device Instance Number throughout the entire BACnet internetwork is also required to
distinguish the device from all other BACnet devices. Device instance can be modified in
Engineering Menu items (dEVH) – high bytes and (dEVL) – low bytes.