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www.DaikinApplied.com 51
IOM 1266-2 • MAGNITUDE
®
MODEL WME CHILLERS
Building Automation
Systems (BAS)
All MicroTech
®
controllers with Open Choices
™
are capable
of BAS communications, providing easy integration and
comprehensive monitoring, control, and two-way data
exchange with open standard protocols such as LonTalk
®
,
Modbus
®
or BACnet
®
.
Daikin Applied unit controllers strictly conform to the
interoperability guidelines of the LonMark
®
Interoperability
Association and BACnet
®
International. They have received
LonMark
®
certification with optional LonWorks
®
communication
module.
Protocol Options
The following protocol options are available:
• BACnet
®
MS/TP
• BACnet
®
IP
• Lon
W
orks
®
• Modbus
®
RTU
The BAS communication module can be ordered with the
chiller and factory-mounted or can be field-mounted at any time
after the chiller unit is installed. Connection to the chiller for all
BAS protocols will be at the unit controller. An interface card or
module, depending on the protocol being used, will have been
factory installed in the unit controller if so ordered, or it can be
field installed.
If an interface module was ordered, the appropriate BAS
interface installation manual was shipped with the unit. If
necessary, contact your local Daikin Applied sales office for a
replacement manual or obtain one from
.
Use with On-Site Generators
All Magnitude
®
Model WME chillers have their compressors
operated with variable frequency drives and, if the unit has two
compressors, the compressors start sequentially in the normal
start/load sequence. These features make Magnitude
®
chillers
especially appropriate for use in applications where they may
be required to run with on-site electrical generators. This is
particularly true when the generators are used for temporary
power when the utility power is lost.
Generator Sizing
Natural gas and diesel generators are sensitive to the peak
current loads of the chiller. Although the normal VFD start
sequence does not require these peak values of current,
certain dynamic conditions such as changes in water flow and
temperature or momentary power interruptions can cause high
peak electrical currents. Use the electrical data either on the
VFD data plate or supplied with the chiller performance rating
sheet – obtained from the Daikin Applied sales office – for
generator sizing purposes. The referenced data will show the
RLA and LRA, which is for each compressor. It is important to
size the generator to handle the LRA value.
WARNING
Generator must be sized by an electrical engineer familiar
with generator applications.
Transfer Back to Grid Power
Due to the special VFD incorporated in all WME chillers
and the system’s inherent ride-through capabilities, transfer
from grid power to stand-by generator power and back to
grid power can be done at any time. The duration of power
interruption during the transfer process will determine how
the chiller will respond. While the compressor rotor is still
spinning at adequate speed, power is generated internally to
keep the bearings and all control electronics operating. Power
interruptions of various durations will cause different restart
scenarios as described below.
1.
Short:
Interruptions of only a few seconds will allow a
running compressor to return to operating speed almost
immediately. (NOTE: If the operating pressure ratio is
high at the time of interruption, there may be a short
delay in return to operating speed.)
2.
Medium:
For interruptions that cause the compressor to
coast down below about 3500 rpm (but still generating
control power), the compressor will continue coasting to
a stop, and then restart.
3.
Long:
Once the compressor coasts nearly to a stop,
control power is lost and the controllers must reboot
normally when either grid power or emergency generator
power is reinstated. (NOTE: If the RapidRestore
®
option
is installed, the time required to restart is reduced to only
.)
Содержание Magnitude WME Series
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