Introduction; The Dac's I/O Points; Independent System Control - Emerson iPro.Genius Installation And Operational Manual

1

Introduction

The Discharge Air Controller (DAC) 
(P/N 818-9001) is a packaged HVAC control board
for use either as a standalone controller or in zone
control applications using a Retail Solutions E2 BX
building control system. The DAC is capable of con-
trolling heat and cool stages, fans, dehumidification
devices, and economizers using on-board I/O and
control algorithms, as well as monitor and interact
with other building control systems and peripherals
(such as smoke alarms and CO2 sensors).
Figure 1-1 - DAC
The DAC supports local physical inputs and out-
puts and communicates with the E2 controller (ver-
sion 3.00 and higher) via the RS485 MODBUS
network.
The E2 will support a maximum of 32 instances of
the DAC to be added to a BX-300 or CX-300. The E2
will support a maximum of 50 DAC devices on a BX-
400 or CX-400.
The DAC supports 15 relay outputs, 6 analog out-
puts, 10 analog inputs, and 10 digital inputs.
Discharge Air Controller (DAC) Manual

1.1. The DAC's I/O Points

The compact size of the DAC allows technicians
to field-mount the DAC in a rooftop unit or enclosure
close to it, allowing for local connection of sensors
and transducers. The board has 10 analog inputs and
20 digital inputs, with default configurations pre-
loaded for quick connection to space temperature
sensors, supply and return air temperature sensors,
and fan proofs. Its 15 relay outputs, rated 2.0 amps
max, are used for activating and deactivating fans,
heat and cool stages, economizers, and other systems
or devices. Its 6 analog outputs may be used for air
damper, modulated heat and cool control, and
variable-speed fan control.
1.2. Independent System
Control
The DAC can control a rooftop unit independently
without the need of a central controller (such as the E2
BX Building Controller). However, the DAC is
designed to interface with an E2 to allow it to work
with other DACs together to control large zones.
Networking the DAC to a central controller also
allows you to view status on E2 and UltraSite32 Site
Manager status screens, report alarms, and log point
values.
The DAC's configuration can be programmed
through the E2 front panel.
Introduction • 1