Johnson Controls VMA1200 Series, VMA1220, VMA1210 Technical Bulletin
ECHNICAL BULLETIN
T
LONW
Systems Manual 1162
ORKS
VMA1200 Section
Issue Date 0501
Variable Air Volume Modular Assembly (VMA) 1200 Series
Overview and Engineering Guidelines
VMA1200 Series Overview and Engineering Guide......................... *3
Introduction........................................................................................................*3
Key Concepts.....................................................................................................*4
VMA1200 Series Models...............................................................................................*4
Definition of Terms........................................................................................................*6
Theory of Operation.......................................................................................................*9
Establish Zones.............................................................................................................12
Room Sensor Placement...............................................................................................12
Pressure Independent VMA...........................................................................................13
VMA Airflow Rate........................................................................................................*13
Power Source.............................................................................................................. *14
ONWORKS
L
Network Topology..................................................................................... *17
Inputs and Outputs...................................................................................................... *19
CablePRO................................................................................................................... *21
CVTPRO.....................................................................................................................*21
Software Too ls ............................................................................................................ *21
Related Documentation............................................................................................... *22
Procedure Overview......................................................................................... 23
Detailed Procedures ........................................................................................*24
Determining VAV Box Requirements........................................................................... *24
Establishing the Room Schedule...................................................................................25
Developing Bills of Material and Placing Orders............................................................26
Configuring the VMA .....................................................................................................27
*Indicates those sections where changes have occurred since the last printing.
© 2001 Johnson Controls, Inc. www.johnsoncontrols.com
Code No. LIT-1162350
2
VMA1200
Appendix A: Reference Information ............................................... *28
Introduction....................................................................................................... 28
VMA Wiring List........................................................................................................... *29
VMA Wiring Interface Diagram....................................................................................*31
VMA Parts List............................................................................................................. *32
FCC Part 15 Label.........................................................................................................33
VMA Specifications ..................................................................................................... *34
Fabricating Your Own Interconnection Cable...............................................................*38
Sensor Interface.......................................................................................................... *39
Appendix B: Application Example.................................................. *42
Single Duct Application Example................................................................................. *42
*Indicates those sections where changes have occurred since the last printing.
VMA1200 Series Overview and Engineering Guidelines
VMA1200 Series Overview and
Engineering Guide
Introduction
The Variable Air Volume Modular Assembly (VMA) 1200 Series is a
configurable, integrated module that includes a Variable Air Volume
(VAV) controller, actuator, and differential pressure sensor. The VMA
is offered as two models: cooling only and cooling with reheat. The
models, which use the LonTalk protocol, are designed for pressure
independent, single duct systems. The reheat model can be used with
parallel or series fan powered boxes.
3
This manual is a reference tool for engineering VMA1200 installations
and applications. It is also a training tool to learn about the
VMA1200 Series controllers. It is task oriented for easy reference to
specific tasks. Refer to the appendixes at the end of this document for
wiring tables and diagrams, a parts list, specifications, and an
application example.
This document describes how to:
• determine VAV box requirements
• establish the room schedule
• develop bills of material and place orders
• configure the VMA
4
VMA1200
Key Concepts
VMA1200 Series Models
Table 1 lists VMA1200 Series features. Table 2 shows available
VMA1200 models.
Table 1: Feature Checklist
VMA Features Comments
Applications
Pattern Recognition Adaptive Control (PRAC)
on Zone Proportional Plus Integral (PI)
Temperature Loops
Adaptive Flow Control Loops No manual tuning, improved control and energy savings
Single Duct, Pressure Independent VAV Meets most VAV applications.
Side Loops without Interlocking Single Analog Input (AI) to Analog Output (AO)/Binary
Fan Powered Boxes Series or parallel
Incremental, Proportional, and Three Stages
of Box Heat
Incremental, Proportional Two Position, or
One Stage Supplemental Heat
Damper Actuator
Clockwise (CW)/Counterclockwise (CCW)
Rotation Selection
Software/Tools
Ability to Download Code Firmware Firmware code is upgradeable without removing the VMA.
Diagnostics
Moving Average Flow/Temperature
Diagnostic
Actuator Duty Cycle Diagnostic Indicates shaft slippage.
Commissioning
Balancing Tool with Automatic K-factor
Calculation
Hardware
24 VAC Isolation Eliminates 24 to 24 VAC transformer and polarity concerns.
Multiple VMAs Powered by a 100 VA
Transformer
Isolated Communication, Binary Outputs, and
24 VAC
Ability to Drive Low Current Relays Down to
25 mA
13-Bit Analog Input/8-Bit Analog Output
Resolution
Analog Input Jumpers Eliminated All analog inputs are preset reducing labor.
Continued on next page . . .
Eliminates manual tuning and seasonal retuning.
Output (BO)
Up to three stages or normally open/closed valves
Normally open or closed valves
Set via M-Pro software, VMA1200 Balancing Tool (VBT)
software, or network management tool for either direction
to close.
Provides standard measure of control loop performance
over time.
Palm compatible handheld device (Version 2.0 or later
operating system) on Zone Bus
Up to 14 cooling only. Number of reheat/fan units depends
on power consumption of valve/fan relays.
Saves installed cost and improved electrical noise
rejection.
Eliminates relay chatter.
High accuracy and good device control
VMA1200 Series Overview and Engineering Guidelines
VMA Features (Cont.) Comments
Differential Pressure Transducer
Dead Ended Transducer No filters or maintenance required.
Capacitive Technology Improved stability
Industry Accepted Flow Measurement
Accuracy
Temperature Sensors
Variety of Sensors Nickel, 1K platinum, 2.25K NTC
Temporary Occupied Button On TMZ1600, TE-6700, TE-7000 (Europe only) Series
Temporary Occupied Light-Emitting Diode
(LED)
LED Indicator for Operation
Power/Communication
Physical
Small, One Piece Assembly
102 x 153 x 102 mm (4 x 6 x 4 in.)
Plenum Plastic Housing Rating UL 94-5VB plenum flammability may eliminate metal box
Removable Input/Output (I/O) Screw
Terminals
Node Installation
Service Pin Message Local pushbutton and remote access from Palm compatible
Wink Function
Bar Code Label
Even for flows below 250 fpm (1.25 m/s) typical
room sensors
On TMZ1600, TE-6700, TE-7000 (Europe only) Series
room sensors for Occupied and Unoccupied modes
Verifies operation and power connections.
Prewired to reduce installed cost.
(check local codes).
Two or three position accessory kits
handheld device
Initiate via Palm compatible handheld device or network
management tool.
Two removable bar code labels printed with Neuron ID
5
6
VMA1200
Table 2: VMA1200 Series Models
Inputs/Outputs Points Rating VMA1210
(Cooling
Only)
Analog Inputs:
Zone Temperature
Zone Setpoint
Humidity, Dewpoint, or Sideloop
Supply Air Temperature or
Supplemental Heat Temperature
Velocity Pressure
Binary Inputs:
Temporary Occupied/
Standby/Room Sensor LED
Occupied
Off or Window or Shutdown
Analog Outputs:
Proportional Heat AO-1 0-10 VDC @ 10 mA
Binary Outputs:
Fan
Box Heat--Incremental Valve or
1-3-stage Electric
Supplemental Heat--Incremental
Valve or 1-3-stage Electric
Actuator Motor
AI-1
AI-2
AI-3
AI-4
Internal
BI-1
BI-2
BI-3
BO-1 to
BO-5
Internal
1K Ni or Pt or 2.25K NTC
1.6K ohm Potentiometer (Pot.)
0-10 VDC
1K Ni or Pt or 2.25K NTC
0-1.75 inch W.C. (0-436 pa)
Dry contact
Dry contact
Dry contact
24 VAC triac @ 0.5A
✔
✔
✔
✔
✔
✔
✔✔
VMA1220
(Cooling
w/Reheat)
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
Definition of Terms
Auto Calibration
The VMA has an Auto Calibration mode that runs periodically to
adjust the pressure sensor calibration due to offset tolerance and
mounting position.
Binding
A process performed by a network management tool that connects
Network Variable Outputs (NVOs) and Network Variable Inputs
(NVIs). These connections provide for peer-to-peer data transfers.
Commissioning
Verification of controller inputs and outputs and modification of the
controller configuration properties to meet installation specifications.
Configuration Properties
Data stored in non-volatile memory (Flash) in the controller that is
accessible from a network management tool.
VMA1200 Series Overview and Engineering Guidelines
Configuring
Building an application within the controller to establish the required
control sequence, setting the functionality of the controller.
Downloading
Writing the Heating, Ventilating, and Air Conditioning (HVAC)
application data and configuration properties to the controller. This is
accomplished using a software tool with a Personal Computer (PC).
7
LONW
Network management system protocol for LONW
ORKS
Network Services (LNS
) Protocol
ORKS
devices.
LONWORKS FTT-10A Transceiver
The Free Topology Transceiver (FTT) interface between the
VMA1200 and the physical network.
M-Pro
A software tool used to configure and download controllers.
M-Pro software is part of the System Tools in M-Tool.
Neuron
The microprocessor used in the VMA. Each neuron has a unique
48-bit ID for node identification.
NVI/NVO
LONM
term for Network Variable Inputs/Outputs. These
ARK
variables may be read/written by network management tools. They
may be bound to other network variables in a system.
Palm Compatible Handheld Device
A handheld computer that uses software to configure and balance the
VMA1200. The PalmPilot unit is an example of this device.
SCPT/UCPT
LONM
Configuration Property Type.
SNVT/UNVT
LONM
A SNVT/UNVT defines the units, structure, and resolution of the
configuration properties, NVIs and NVOs.
terms for Standard Configuration Property Type and User
ARK
term for Standard/User Network Variable Types.
ARK
8
VMA1200
Test and Balance (TAB)
Test and Balance (TAB) is a function performed to ensure the installed
system operates to design specifications. Balancing of the VMA zone
indicates whether the VAV terminal box achieves minimum/maximum
airflow settings. TAB must also be performed for the air handler and
the air duct distribution to the VAV box.
Variable Air Volume (VAV) Controller
An Application Specific Controller (ASC) used for digital control of
single duct, dual duct, fan powered, and supply/exhaust VAV box
applications.
Variable Air Volume Modular Assembly (VMA)
Includes a digital controller with integrated pressure transducer and
actuator.
Zone Bus
A local interface between the controller and the room sensor. By
connecting a Palm compatible handheld device with the proper
software to the CablePRO or CVTPROx00-0 and room sensor, the
Zone Bus allows you to monitor and commission directly through the
room sensor.
Theory of Operation
VAV systems are most easily understood by considering them as
cooling applications. As the zone temperature increases due to heat
produced by people, computers, or other heat sources, the VMA opens
the VAV box damper and lets cooler air in. The size of the space and
the internal and external heat loads dictate the volume of air required
to maintain a zone temperature setpoint. In addition, since the size of
the VAV box dictates its maximum cooling capacity, VAV box
performance is dependent upon the design engineer sizing the box for
each zone. If the installed unit is too small, insufficient cooling results,
and excessive flow rates cause audible noise. If the installed unit is too
large, proper control is difficult to maintain, since a small change in
damper position causes excessive airflow change. Boxes are
sometimes oversized to ensure quiet operation or to reserve cooling
capacity as zone usage changes.
A cooling only VAV system maintains a constant zone temperature
while varying the flow of air to the space. This is unlike a constant
volume system that maintains a constant volume of airflow to the
space but varies the temperature of the air stream in response to space
temperature changes. VAV systems are predominantly single duct, but
some are dual duct designs. The VMA can be configured for most
single duct pressure independent VAV applications. The M-Pro
software (part of M-Tool Release 2.0) is used to configure and
download VMA1200 applications.
VMA1200 Series Overview and Engineering Guidelines
9
The actuator drives the damper from full open to full closed in
90 seconds. The VMA incorporates flow feedback to accurately
position the damper and to minimize position hunting and motor
runtime. Control performance metrics are recorded and are available
via network variables to the Metasys Operator Workstation (OWS).
Figure 1 shows the VMA1200 in the Metasys Network. Figure 2 is a
functional block diagram of the VMA1200.
10
VMA1200
Operator Workst at i on
(with OWS, M-Pro,
and LNS S of tware)
LW
ON ORKS
Compatible
Devices
VMA1200
N1 LAN
Network Control Module (NCM)
LW
ON ORKS
Network
Bus
VMA1200
Zone
Bus
Room
Sensor
Palm Compatible
Handheld Device
CVTPRO
Converter
FTT-10
CablePRO
Converter
Zone
Bus
Room
Sensor
Palm Compatible
Handheld Device
MNET
Figure 1: VMA1200 Controllers in Metasys Network Diagram
VMA1200 Series Overview and Engineering Guidelines
ON ORKS
L W Network
FTT-10
Interface
11
Window Open
Occupancy Sensor
Temp Occ Button
Space Temperature
Space Set point
Auxiliary Temperature
Auxiliary 0-10V
Low
Neuron
Digital
Inputs
x3
Analog
Inputs
x5
Hi
Differential
Pressure
(DP) Sensor
Application
Processor
COP8
IO Processor
Isolated
Phone
Jack
Zone
Bus
Analog
Output
x1
Triac
Outputs
x7
CW CCW
Actuator
Motor
Fblock2
TE-670 0, TMZ1600, or
Palm Compatible
Handheld Device
Heating Valve
Five 24 VAC Outputs for
Fan, Staged Heating, etc.
Figure 2: VMA1200 Functional Block Diagram
12
VMA1200
Establish Zones
When designing VMA systems, establishing zones correctly is critical
to take maximum advantage of the VMA’s exceptional accuracy and
rapid response capabilities.
The designer strives for the most uniform indoor environmental
conditions possible. A single thermostatic device (room sensor)
controls each area. A zone could also be thought of as an area where
the load is considered the same for every square foot of floor space.
HVAC system zones fall into two major categories: exterior zones and
interior zones. Exterior zones are spaces directly affected by outdoor
weather conditions. Heat losses or outdoor air conditions do not
influence interior zones. Interior zones usually have cooling or
ventilation requirements only.
Further divisions of interior/exterior zones may be required to
accommodate different occupancy schedules and/or solar loads.
Variations in internal loading dictate the selection of separate zones.
For example, in a restaurant, the kitchen has vastly different heating
and cooling requirements from the seating area.
Room Sensor Placement
Consider room sensor placement for each zone, making sure to:
• Verify that the room sensor is the correct one for the application.
• Review architectural requirements such as furniture height and
location, aesthetics, and type of mounting. Wall plates are required
if mounting on a conduit handibox.
• Review room sensor location. The best room sensor location is on
an interior wall, about five feet above the floor, out of direct
sunlight, out of the direct path of supply air from the diffuser, away
from heat sources, such as equipment, machines, and perimeter
radiation, and away from doors and other draft sources. Mounting
height may be affected by local codes or the accessibility needs of
persons with disabilities.
• Do not locate a sensor near zone boundaries where primary
influence is from an adjacent zone.
VMA1200 Series Overview and Engineering Guidelines
Pressure Independent VMA
The pressure independent VMA employs patented self-tuning,
cascaded proportional/integral control loops. The zone temperature
loop samples space temperature and resets the airflow setpoint
between the minimum and maximum flow settings. Since inlet duct
static pressure influences the amount of air passing through the
VAV box, the VMA airflow loop samples airflow via a flow pickup in
the box inlet. It modulates the damper to control the flow. Thus, the
VAV box flow is independent of duct static pressure.
The engineering basis for this method of control is that the temperature
of a space with a constant load is linearly proportional to the flow of
conditioned air into the space. The engineer must accurately determine
the required maximum and minimum flow for each space based on
heating, cooling, and ventilation loads.
VMA Ai r fl o w Ra t e
The VMA determines airflow rate by dynamic pressure measurement.
The VMA contains a Differential Pressure Transmitter (DPT) to sense
differential pressure in pressure independent VAV applications.
13
The DPT is connected to the VAV box airflow pickups. It measures
differential pressure and generates a proportional voltage signal. The
voltage signal from the DPT is read by the VMA and converted to
airflow in cubic feet per minute (cfm) or liters per second.
The DPT provides maintenance-free performance within the control
range of 1.25 to 18 m/s (250 to 3500 feet per minute [fpm]) when used
as recommended.
The minimum 1.25 m/s (250 fpm) velocity and the gain of the airflow
pickup produce an accurately measured pressure difference.
The VMA Auto Calibration function helps reduce the temperature
effect error by zeroing offset errors. As the ambient temperature
swings relative to the temperature at which the Auto Calibration
occurred, an offset error may occur (typically ±0.179 Pa/°C
[±0.0004 inch W.C./°F]). When calibration occurs, this error becomes
zero.
The error envelope becomes smaller with increased airflow pickup
gain and with smaller ambient temperature deviations at the
transmitter location.
14
Power Source
VMA1200
You can use one 24 VAC power trunk to power multiple VMAs. In
this case, transformers of up to 100 VA are centrally located, and the
secondary run is without conduit and without concern about polarity.
Notes: The 24V power transformer must be UL/CSA listed as
NEC Class 2 Power Limited.
See NEC Article 725/Class 2 (30 VRMS maximum) and
(100 VA maximum).
The VMA1210 draws 7 VA including the internal damper actuator.
Therefore, 14 VMAs can be powered from one 100 VA transformer
without conduit. The number of VMA1220s is dependent on the
binary output loads and reheat actuators. The reheat actuators must be
added to the 7 VA of the controller, then divided into the 100 VA
transformer power. For example, the VMA1220 draws 7 VA without
loads. If there were only a single VA-8020 reheat valve per VMA, its
4 VA must be added to the VMA for a total of 11 VA. Then
nine VMA/VA8020s can be powered from one 100 VA transformer.
Table 3 shows the power rating for several cooling/heating coil valve
actuators. The valve power plus the VMA power must not exceed
100 VA. If a device is not listed in the following table, refer to the
product literature for that device.
Table 3: Actuator VA Power Rating
Actuator Type Power Rating
VA-8020
VA-8050
VA-7200
J Series Electric Zone Valve
VA-8022
VA-8052
VA-7202
VA-7450
VA-7452
VA-7050
VA-7310
VA-7312
VA-7010
VA-7150
VA-7152
Incremental 4 VA
Incremental 6 VA
Incremental 6.7 VA
On Off 7 VA
Voltage (0 to 10 VDC) 4 VA
Voltage (0 to 10 VDC) 6 VA
Voltage (0 to 10 VDC) 6.7 VA
Incremental 2.5 VA
Voltage (0 to 10 VDC) 2.5 VA
Thermal (DAO) 3 VA
Incremental 2 VA
Voltage (0 to 10 VDC) 2 VA
On/Off 7 VA
Incremental 2.7 VA
Voltage (0 to 10 VDC) 4.7 VA
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