| Controls 20 - 60 Tons
Figure 31-1
— Human Interface Display
The CGAF chiller is controlled by an
IntelliPak® microcomputer-based controller.
IntelliPak provides better control, as well as several
other important benefits.
Customized Control With IntelliPak controls, Trane can customize controls around the chiller application
and the specific components used in the CGAF. For
instance, the compressor protection system is specifically designed for the Trane 3-D® Scroll compressor. A leaving chilled solution temperature control algorithm maintains
accurate temperature control, for both comfort and
process applications, minimizing the drift from setpoint. The IntelliPak controls incorporate
improved chiller start-up, load limiting, compressor
anti-recycle timing and lead/lag functions into standard chiller operation. Interface with outside systems such as building automation controls is flexible and easy.
Simple Interface with All Control
Systems
The IntelliPak controls afford simple
interface with Trane Tracer® systems, providing broad control capabilities for Building
Automation systems. For control systems other than
Trane, two generic building automation system interfaces are available and offer simplicity and flexibility in accessing unit functions.
Safety Controls
A centralized microcomputer offers a
higher level of machine protection. Since the safety controls are smarter, they
limit compressor operation to avoid compressor or
evaporator failures, thereby minimizing nuisance
shutdown. For instance, the Unit Control Module (UCM) will provide condenser low pressure
control by staging condenser fans on or off in an
effort to maintain the saturated condensing temperature
within a fixed range. Overall, the safety controls help keep the cooling system
on-line and operating safely.
Monitoring and Diagnostics
Since the microcomputer provides all
control functions, it can easily indicate such parameters as leaving chilled solution temperature and capacity staging. If
a failure does occur, the diagnostic alarm will be
displayed giving specific information about the failure. All of the monitoring and diagnostic information can be easily accessed
at the Human Interface display, standard on every unit.
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