Johnson Controls VMA 1420 - User Manual

Technical Bulletin
Issue Date February 28, 2006
Variable Air Volume Modular Assembly (VMA) 1400
Series Overview and Engineering Guidelines
VMA1400 Series Overview and Engineering Guidelines ...................2
Introduction......................................................................................................... 2
Key Concepts...................................................................................................... 3
VMA1400 Series Models...................................................................................................3
VAV System......................................................................................................................6
Definition of Terms............................................................................................................9
Room Sensor Placement ................................................................................................10
Pressure Independence..................................................................................................10
VMA Airflow Rate............................................................................................................10
Power Source..................................................................................................................11
N2 Bus Rules ..................................................................................................................12
Inputs and Outputs..........................................................................................................13
Zone Bus.........................................................................................................................14
CablePRO.......................................................................................................................15
CVTPRO .........................................................................................................................15
Related Documentation...................................................................................................16
Application Examples......................................................................................................17
Reference Information.....................................................................................................26
Specifications..................................................................................................................27
Detailed Procedures......................................................................................... 32
Determining VAV Box Requirements..............................................................................32
Establishing the Room Schedule ....................................................................................32
Developing the Bill of Material and Placing Orders.........................................................33
Configuring the VMA.......................................................................................................35
© 2006 Johnson Controls, Inc. www.johnsoncontrols.com
Code No. LIT-6363120

Johnson Controls VMA 1420 Specifications

General

Model	VMA 1420
Input Voltage	24 VAC ±20%, 50/60 Hz
Number of Universal Inputs	4
Number of Binary Outputs	2
Control Algorithm	PID
Type	VAV Controller
Operating Temperature	-40 to 158°F (-40 to 70°C)
Storage Temperature	-40°F to 158°F (-40°C to 70°C)
Weight	0.6 kg
Communication Protocol	BACnet MS/TP
Temperature Sensor	thermistor type
Product Type	Variable Air Volume (VAV) Controller

Summary

Introduction

Key Concepts

VMA1400 Series Models

Introduces the different VMA1400 models and their features.

VAV System

Explains the theory of operation for VAV systems.

Definition of Terms

Provides definitions for key terms used in the document.

Room Sensor Placement

Guidelines for optimal placement of room sensors for accurate readings.

Pressure Independence

Explains the pressure independent control method used by the VMA.

VMA Airflow Rate

Details how the VMA measures and determines airflow rate.

Power Source

Information on the required power supply and connections for the VMA.

N2 Bus Rules

Outlines the rules and specifications for the N2 communication bus.

Inputs and Outputs

Describes the available input and output terminals on the VMA.

Zone Bus

Details the Zone Bus communication protocol and specifications.

CablePRO

Information on the CablePRO interface device for VMA communication.

CVTPRO

Information on the CVTPRO interface device for VMA communication.

Related Documentation

Lists other relevant documents for VMA system information.

Application Examples

Provides practical examples of VMA applications in different HVAC scenarios.

Detailed Procedures

Determining VAV Box Requirements

Steps for selecting the appropriate VAV box for a given application.

Establishing the Room Schedule

Guidance on creating the room schedule for system configuration.

Developing the Bill of Material and Placing Orders

Procedures for creating a bill of materials and ordering VMA components.

Configuring the VMA

Step-by-step instructions for configuring the VMA controller.