Mixed Air Dual Duct (MADD) Air Handling Unit (AHU) Application Note

110 Pages·2008·2.12 MB·English

Application Note Mixed Air Single Duct Air Handling Unit
Issue Date December 4, 2008

Mixed Air Dual Duct (MADD) Air Handling Unit (AHU)
Application Note
Mixed Air Dual Duct (MADD) Air Handling Unit (AHU) Application Note
.....................................................................................................................4
Introduction............................................................................................................4
Related Documentation.........................................................................................6
Key Concepts.........................................................................................................7
State Based Control.............................................................................................................7
Occupancy Determination....................................................................................................8
Temperature Control Strategies...........................................................................................9
Discharge Air Temperature (DAT) Control.....................................................................9
Discharge Air Temperature Reset by Outside Air Temperature.....................................9
Occupied Control Schemes.................................................................................................9
Unoccupied Control Sequencers.......................................................................................14
Discharge Air Unoccupied Sequencer.........................................................................14
Sequencers........................................................................................................................17
Emergency Mode.........................................................................................................17
No Airflow.....................................................................................................................18
Unit Enable...................................................................................................................19
Start Stop Sequencer...................................................................................................19
Control of Staged Devices.................................................................................................23
Discharge Air Control of Staged Devices.....................................................................23
Device Availability Determination.................................................................................23
Output Device Control........................................................................................................24
Damper........................................................................................................................24
Preheat.........................................................................................................................28
Heating.........................................................................................................................32
Cooling.........................................................................................................................35
Supply Fan...................................................................................................................38
Return Fan...................................................................................................................40
Humidification...............................................................................................................42
PID Tuning.........................................................................................................................43
Integral Time................................................................................................................43
Proportional Band........................................................................................................43
Saturation Time............................................................................................................43
FX Builder Application Wizard Concepts ..........................................................45
© 2008 Johnson Controls, Inc. www.johnsoncontrols.com
Code No. LIT-12011290
Mixed Air Dual Duct (MADD) Air Handling Unit (AHU) Application Note 2
Installing the MADD AHU Application Package.................................................................45
Selecting the MADD AHU Application Template................................................................48
Configuring the MADD AHU Application............................................................................49
Configuring the Control Strategy..................................................................................49
Adjusting Setpoints......................................................................................................53
Adjusting Parameters...................................................................................................54
Adjusting Proportional Plus Integral Plus Derivative (PID) Parameters.......................58
Configuring the Internal Occupancy Schedule.............................................................60
Viewing the Configuration Summary............................................................................61
Viewing Required Inputs and Outputs..........................................................................62
Selecting the User Interface(s) and Supervisor Interface..................................................63
Selecting the Target Device...............................................................................................64
Configuring the Hardware I/Os...........................................................................................65
Generating the Application Files and Documentation........................................................67
Viewing Generated Application and Documentation Files...........................................69
Reviewing an Exported Application File.............................................................................69
FX CommPro Concepts.......................................................................................71
User Interface Concepts......................................................................................71
Medium User Interface.......................................................................................................71
Medium User Interface Capabilities.............................................................................72
Medium User Interface Navigation...............................................................................72
Status Folder................................................................................................................74
Modes Folder...............................................................................................................76
Configuration Folder.....................................................................................................78
Setpoints Folder...........................................................................................................81
Parameters Folder.......................................................................................................82
PID Parameters Folder................................................................................................84
Balancer Folder............................................................................................................85
Time Folder..................................................................................................................87
Schedulers Folder........................................................................................................88
Password Folder..........................................................................................................88
MUI Status LEDs..........................................................................................................88
Accessing a Folder in the MUI.....................................................................................89
Changing a Configuration Setting, Setpoint, or Parameter in the MUI.........................89
LCD2x4 User Interface.......................................................................................................90
LCD2x4 User Interface Capabilities.............................................................................91
LCD2x4 User Interface Navigation...............................................................................91
Config 1 Page..............................................................................................................93
Config 2 Page..............................................................................................................95
Analog Inputs Page......................................................................................................96
Digital Inputs Page.......................................................................................................96
Analog Outputs Page...................................................................................................97
Digital Outputs Page....................................................................................................97
Setpoints 1 Page..........................................................................................................98
3 Mixed Air Dual Duct (MADD) Air Handling Unit (AHU) Application Note
Setpoints 2 Page..........................................................................................................99
Parameters 1 Page......................................................................................................99
Parameters 2 Page....................................................................................................101
PID Parameters Page................................................................................................102
Modes Page...............................................................................................................103
Time Page..................................................................................................................106
Balancer Page............................................................................................................107
FX Setup....................................................................................................................108
Password Page..........................................................................................................108
Events Page...............................................................................................................109
Schedulers Page........................................................................................................109
Graphical Status Icons...............................................................................................109
Accessing a Page in the LCD2x4 UI..........................................................................109
Changing a Configuration Setting, Setpoint, or Parameter in the LCD2x4 UI............109
Supervisor Interface..........................................................................................110
Mixed Air Dual Duct (MADD) Air Handling Unit (AHU) Application Note 4
Mixed Air Dual Duct (MADD) Air
Handling Unit (AHU) Application
Note
Introduction
This application note introduces the standard Mixed Air Dual Duct Air
Handling Unit (MADD AHU) controller application template, provides
procedures to configure the application using FX Builder’s Application
Wizard, and procedures to commission the system using the Integral and
Medium User Interface and FX CommPro.
The MADD AHU application template consists of a single application
software file which includes multiple configuration options and control
strategies for controlling many different types of air handlers. You use
FX Builder’s Application Wizard to select the specific configuration
options and control strategies for your specific MADD AHU control
requirements. The available control strategy configuration options appear
in Table 1.
Table 1: MADD AHU Configuration Options
Configuration Setting Allowable Options
Temperature Control Strategy Discharge Air Temperature Control
Discharge Air Temperature reset by Outside Air
Temperature
Type of Preheat None
Staged (up to four stages)
Face and Bypass (2-position or proportional valve)
Proportional valve
Staged Preheat Control Type Equal Runtime
First On/Last Off
Type of Cooling None
Staged (up to 4 stages)
Face and Bypass (2-position)
Proportional valve
Staged Cooling Control Type Equal Runtime
First On/Last Off
Continued on next page . . .
5 Mixed Air Dual Duct (MADD) Air Handling Unit (AHU) Application Note
Configuration Setting (Cont.) Allowable Options
Type of Heating None
Staged (up to 4 stages)
Face and Bypass (2-position)
Proportional valve
Staged Heating Control Type Equal Runtime
First On/Last Off
Economizer Type None
Dry Bulb
Differential Temperature
Single Enthalpy
Differential Enthalpy
Supply Fan Type Constant Volume
Variable Volume
Return Fan Type None
Constant Volume
Supply Fan Tracking
Building Pressure Control
IAQ/CO2 Control Enable
Disable
Humidification Enable
Disable
Alarm Options High Static Pressure Alarm
Mixed Air Low Limit Alarm
Supply Fan Proof
Smoke Alarm
Reset after Loss of Airflow Manual
Automatic
Power Fail Restart Enable
Disable
Mixed Air Dual Duct (MADD) Air Handling Unit (AHU) Application Note 6

Figure 1: Facility Explorer MADD AHU Application Architecture
Related Documentation
Table 2: Related Documentation
For Information On See Document LIT or Part Number
FX15 Overview Information FX15 Field Controller LIT-12011082
Product Bulletin
FX15 Technical Information FX15 Controller Technical LIT-12011107
Bulletin
FX16 Overview Information FX16 Master Controller LIT-12011084
Product Bulletin
FX16 Technical Information FX16 Master Controller LIT-12011108
Technical Bulletin
7 Mixed Air Dual Duct (MADD) Air Handling Unit (AHU) Application Note
Key Concepts
State Based Control
The MADD AHU application uses State Based Control to ensure proper
control of the air handling unit. State Based applications have the
following components.
• Inputs: Extract information from the system. Examples include
hardwired sensors (for example, discharge air temperature sensor),
switches (for example, proof of airflow switch), and network overrides
(for example, networked outside air temperature).
• Parameters: Refer to pieces of information stored inside the
application. Examples include configuration settings, setpoints, unit
parameters, and Proportional plus Integral plus Derivative (PID)
parameters. Many parameters are adjustable.
• Miscellaneous Logic: Defines all logic not defined via a State
Generator or Output Controller. Examples include occupancy
determination and active setpoint determination.
• State Generators: Defines the sequences of operation for a specific
control system. State generators need information from the appropriate
inputs or parameters or status information from the output controllers
to ensure proper sequencing.
• State Selector: Receives state information from all of the state
generators. The state selector then determines the current set of output
controller modes based on the current states of all the state generators.
• Output Controllers: Defines the operation of the output devices (for
example, valves, dampers, and fans) based on the modes determined
by the State Selector.
• Outputs: Converts the output controller information into action.
Examples include valve and damper outputs, fan commands, and
cooling and heating stage commands.

Figure 2: State Based Control Diagram
Mixed Air Dual Duct (MADD) Air Handling Unit (AHU) Application Note 8
Occupancy Determination
The MADD AHU application:
• supports a local and network occupancy schedule with the network
schedule having priority
• supports a local and network occupancy sensor with the network
occupancy sensor having priority
• has a temporary occupancy input and a network occupancy manual
command with the network occupancy manual command having
priority
Table 3 displays the occupancy determination for the MADD application.
Table 3: Occupancy Determination
Inputs Result
Occupancy Manual Occupancy Occupancy Effective
Command Schedule Sensor Occupancy
Occupied − − Occupied
Unoccupied Unoccupied
Bypass Occupied Occupied
Unoccupied Bypass
Bypass Bypass
Standby Bypass
Invalid Occupied Occupied
Unoccupied Bypass
Standby − − Standby
Invalid Occupied Occupied Occupied
Unoccupied Standby
Invalid Occupied
Unoccupied − Unoccupied
Bypass Bypass
Standby Standby
Invalid Occupied Occupied
Unoccupied Unoccupied
9 Mixed Air Dual Duct (MADD) Air Handling Unit (AHU) Application Note
Temperature Control Strategies
The MADD AHU application supports the following selectable
temperature control strategies.
Discharge Air Temperature (DAT) Control
The MADD AHU sequences the controlled devices to control the
discharge air temperature to a constant setpoint.
Discharge Air Temperature Reset by Outside Air Temperature
The MADD AHU uses the outside air temperature to calculate a discharge
air temperature setpoint. When the outside air is warm, the discharge air
temperature setpoint resets down. When the return air is cold, the
discharge air temperature setpoint resets up. The MADD AHU sequences
the controlled devices to control the discharge air temperature to this
calculated setpoint. See Figure 3.

Figure 3: Discharge Air Temperature Reset by Outside Air Temperature
Occupied Control Schemes
The MADD application uses two sequencers to control the heating and
cooling devices. The mixed air damper, preheat, and cooling are
sequenced using the Occupied Sequencer, and the heating is sequenced
using the Hot Deck Sequencer. See Table 4 for Occupied Sequencer
modes and Table 5 for Hot Deck Sequencer modes.
Mixed Air Dual Duct (MADD) Air Handling Unit (AHU) Application Note 10
Table 4: Occupied Sequencer
State Description
Satisfied Enters this state when no heating or cooling is required.
Cooling Idle Enters this state through Satisfied whenever the state is enabled. In
this state, the output controllers hold their last command. This state
allows the fans to start and obtain an accurate outside air and
discharge air temperature reading.
Heating Idle Enters this state through Satisfied whenever the stated is enabled. In
this state, all of the output controllers hold their last command. This
state is used to wait for the fans to start.
Econ Enters this state if cooling is required and the economizer is available.
In this state, the mixed air damper controls the process variable.
EconMech Enters this state if, after being in the Econ state, the damper PI loop
has saturated high. In this state, the damper opens to its maximum
position and the cooling output controllers control the process variable.
Mech Enters this state if cooling is required and the economizer is not
available. In this state, the damper closes to the minimum position and
the cooling controls the process variable.
Preheat Enters this state when the preheat output controller controls the cold
deck air temperature to the cold deck setpoint.
Heat The Preheat state is set to maximum.
Shutdown Enters this state if the process variable is unreliable.

Table 5: Hot Deck Sequencer
State Description
Satisfied Enters this state when no heating or cooling is required.
Heating Idle Enters this state through Satisfied whenever the state is enabled. In
this state, the output controllers hold their last value. This state is used
to wait for the fans to start.
Control In this state, the heating output controller controls the hot deck
discharge air temperature to the hot deck setpoint.
Shutdown Enters this state if the process variable is unreliable. All heating and
cooling devices are turned off.