Emerson E2 operation manual Zone Control, How Zones Work, Suction Group Outputs

Output Device	Wire 8RO contacts	Set Fail-safe Dip	Notes
	to:	Switch to:
Heat / Cool	see note	see note	Set up any stages you want ON when the controller is off-
Staged Outputs			line as N.C. Stages you want OFF should be set as N.O.
Single-Speed	see note	see note	If one or more heat or cool stages will be ON, wire fan
Fans			N.C. so it will be active during controller off-line times.
			Otherwise, wire N.O.
Two-Speed Fans	see note	see note	If any heat or cool stages are configured to be ON (N.C.),
(LOW, HIGH,			set the wiring and the switch to N.C., and set either the
and fan contac-			LOW or HIGH stage output to N.C. (whichever speed
tor)			you want active). If no heat or cool will be active, set
			LOW, HIGH, and the fan contactor to N.O.
Digital Econo-	N.O.	N.O.
mizer
Table 11-11- Suction Group Outputs

11.7 Zone Control

11.7.1 Overview

An HVAC Zone is a collection of up to sixteen rooftop units or air handling units that work together to maintain the same temperature and humidity throughout a particular volume of space. The primary function of an HVAC Zone is to “manage” the operation of each individual HVAC unit by providing the temperature setpoints that will be used in Temperature Control. Zones are also responsible for ordering HVAC units to dehumidify and determining when outside air conditions are favorable to economize.

11.7.2 How Zones Work

A Zone is built by first creating a Zone application in the E2 BX. Then, all HVAC unit applications that will be a part of the Zone must be connected with the Zone applica- tion. This connection process is known as association.

When a rooftop unit or AHU is associated with a Zone, the E2 automatically makes a series of I/O connections between the Zone application and the individual MultiFlex RTU or AHU application. From that point on, the Zone is responsible for passing along the following information to the individual unit:

•The heating and cooling setpoints it will use during occupied and unoccupied building times.

•A command to operate in either occupied or unoccupied mode (based on the Zone appli- cation’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 econo- mization checking method).

•A signal to begin or end dehumidification (based on the Zone application’s own humid- ity reading and dehumidification setpoint).

•A signal indicating the current season is either SUMMER or WINTER.

•The combined Zone Temperature and Zone humidity (based on a combination of each HVAC unit’s space temperature and space humidity).

•The fallback temperature and humidity set- points to use in case the unit loses contact with its Zone application.

Zone Control Software Overview • 11-25