Honeywell AUTOMATIC CONTROL User Manual

ENGINEERING CMANUAL OF AUTOMATION CONTROL
AIR HANDLING SYSTEM CONTROL APPLICATIONS
216
CONDITIONS FOR SUCCESSFUL OPERATION
Local weather data analysis needed to determine the optimum
changeover setpoint. The analysis need only consider data when the
OA is between approximately 60°F and 78°F, and during the occupancy
period.
NOTE: The dry bulb economizer decision is best on small systems
(where the cost of a good humidity sensor cannot be
justified), where maintenance cannot be relied upon, or
where there are not frequent wide variations in OA RH
during the decision window (when the OA is between
approximately 60°F and 78°F).
SPECIFICATIONS
A global economizer function shall be provided to switch all AHUs
from OA cooling to minimum OA based upon an OA temperature
setpoint. Software shall also be provided to allow the user to override
the decision from being based upon OA dry bulb (with an appropriate
commandable setpoint), to manually lock the system into or out of the
economizer mode.
ECONOMIZER CYCLE DECISION—OUTDOOR AIR ENTHALPY CONTROL
Functional Description
16.8
OA
MA
RA
EA
27.0
1
22
ON
ECONOMIZER MODE SELECTOR
OA MINIMUM SETPOINT
(NOTE: THE TEST AND BALANCE INITIAL
VALUE FOR PROPER VENTILATION IS 22)
OTHER INPUTS
AND OUTPUTS
ECONOMIZER
STATUS
ENTHALPY
BTU PER POUND
M10455
4
7
5
9
3
6
83
8
1 2
83
CONTROL
PROGRAM
1 = AUTO BASED UPON OA
ENTHALPY BELOW BTU PER POUND
72.0
81.0
2 = AUTO BASED UPON OA DB
TEMPERATURE BELOW DEGREES
3 = MANUAL, ECONOMIZER ON.
4 = MANUAL, ECONOMIZER OFF.
NOTE: THE SYSTEM IS LOCKED OUT OF
THE ECONOMIZER MODE ANYTIME
THE OA DRY BULB IS
ABOVE DEGREES.
49
52
Item
No. Function
1 Sensor senses OA temperature.
2 Sensor senses OA humidity.
3OA enthalpy calculated from OA temperature
and humidity.
4 Economizer mode decision selector, including
OA enthalpy setpoint below which the
economizer decision is invoked, and command
schedule.
5 Economizer decision status (operator
information).
6 Setpoint for minimum OA damper position.
7 Actuator positions OA and RA dampers.
8 Actuator positions EA dampers.
9 Control program coordinates occupancy,
temperature, smoke, and ventilation controls.

Honeywell AUTOMATIC CONTROL Specifications

General

Brand	Honeywell
Model	AUTOMATIC CONTROL
Category	Controller
Language	English