Daikin AWV024 - System Architecture; Modbus Communication - Unit

ConTroller operaTIon
www.DaikinApplied.com 43 IOM 1242-2 • PATHFINDER
®
MODEL AWV CHILLERS
System Architecture
The overall controls architecture uses the following:
• One MicroTech
®
III unit controller
• I/O extension modules (sometimes referred to as
“controllers”) as needed depending on the conguration
of the unit
• Up to three BAS interface modules as needed based on
installed options
Modbus Communication - Unit
The unit controller (UC) communicates to the compressor
VFD’s and the EXV modules via the Modbus RTU connection
on the controller itself. Communication to the VFD’s and EVAP
EXV MODULE is required for operation in all congurations.
Communication to ECON EXV MODULE is required only if the
chiller is congured with economizers.
Figure 60: System Architecture Schematic
NOTE: Graphic shows typical chiller controller arrangement; individual chiller congurations will be as ordered.
Compressor
VFD 2
Compressor
VFD 1
Alarm/Limit
I/O Extension
Circuit 1
I/O Extension
Circuit 2
I/O Extension
Evap EXV
Module
Economizer EXV
Module
RapidRestore®
I/O Extension
BAS Comm
Interface
Module
BAS Comm
Interface
Module
BAS Comm
Interface
Module
Unit Controller
DC
Fan
DC
Fan
DC
Fan
Modbus
...
DC
Fan
DC Fan Controller
Modbus
Peripheral Bus