Emerson Site Supervisor, Руководство пользователя

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HVAC Zone Software Overview
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When a rooftop unit or AHU is associated with an
HVAC Zone, the Site Supervisor automatically makes a
series of I/O connections between the HVAC Zone
application and the individual MultiFlex RTU or AHU
application. From that point, the HVAC Zone is
responsible for passing the following information to the
individual unit:
• The heating and cooling setpoints that the unit
will use during occupied and unoccupied building
times.
• A command to operate in either occupied or
unoccupied mode (based on the HVAC Zone
application’s own time schedule input).
• Outdoor air and outdoor relative humidity values.
• A signal to enable or disable economization
(based on the Zone application’s own
economization checking method).
• A signal to begin or end dehumidification (based
on the Zone application’s own humidity reading
and dehumidification setpoint).
• A signal indicating the current season is either
SUMMER or WINTER.
• The combined HVAC Zone Temperature and
HVAC Zone humidity (based on a combination of
each HVAC unit’s space temperature and space
humidity).
• The fallback temperature and humidity setpoints
to use in case the unit loses contact with its HVAC
Zone application.
5.22.2 Compatible Applications to
be Connected to HVAC
Zones
There are three different HVAC applications that may
be associated with an HVAC Zone application:
• a MultiFlex RTU application
• a MultiFlex RCB application
• an AHU application
The MultiFlex RTU and RCB applications interface
with the MultiFlex RTU and RCB I/O Network boards that
control rooftop units. AHU applications use input and
output points on the I/O Network to control air handling
units.
5.22.3 Temperature Control
HVAC Zone applications do not control temperature
themselves. HVAC Zone applications pass along the
setpoints that an HVAC unit will use. The individual unit
is responsible for controlling the setpoint using its own
temperature input.
The HVAC Zone application pass along eight different
setpoints, which are shown in
Table 5-14
. The application
that receives the setpoints can only use one cooling and
one heating setpoint. The pair of setpoints the application
will use determines whether the current season is SUM-
MER or WINTER and whether the building is OCCU-
PIED or UNOCCUPIED (both of which are supplied by
the Zone).
5.22.4 HVAC Zone Temperature
Each MultiFlex RTU and AHU application has a space
temperature output that is equal to the unit’s current
Control Temperature. When associated with an HVAC
Zone application, this space temperature output is
connected to one of the 16 HVAC Zone Temperature
inputs in the HVAC Zone application. These 16 inputs are
combined using a user-defined combination method to
yield the HVAC Zone Temperature.
HVAC Zone Temperature provides an overview of the
unit’s performance in heating and cooling within the
HVAC Zone. The HVAC Zone Temperature can be used as
a temperature control input by one or all of the HVAC
Zone’s application.
5.22.5 Economizer Control
An HVAC Zone application is responsible for
analyzing outside air conditions and determining if the
conditions are suitable for bringing in outside air. If the air
condition is suitable, the HVAC Zone sends a signal to its
associated HVAC units telling them that economization is
OK. If not, it sends a signal to disable economization.
It is up to the associated HVAC unit to process the
economization information and open the dampers.
5.22.6 Economization Enable
There are possible ways an HVAC Zone application
may determine when conditions are favorable for
economization:
1. Enthalpy Switch - An enthalpy switch is a digital
Cooling Heating
SUMMER COOL OCC
SUMMER HEAT OCC
SUMMER COOL UOCC SUMMER HEAT UOCC
WINTER COOL OCC WINTER HEAT OCC
WINTER COOL UOCC
WINTER HEAT UOCC
Table 5-14
- Cooling/Heating Setpoints