8/3/2019 DDC guide

1/2

DDC OnlineDIRECT DIGITAL CONTROLS

Getting Started

An Overview of Direct Digital Controls

Purpose of this Guide:

Due to the complexity and proprietary nature of DDC systems, its challenging to stay current with the designs,

installations, operation and maintenance of DDC systems. DDC-Online.org was developed specifically to help

building owners and consulting/specifying engineers with these issues. Getting Startedis a tool to help

professionals make more informed decisions and increase their knowledge about direct digital controls.

Chapter 1: Introduction to Direct Digital Control Systems

In this chapter:

This chapter covers the basics of an Energy Management System a fully functional control system.

Read this chapter.

Chapter 2: Control Response

In this chapter:

A review of five control responses and of the main benefits of DDCimproved effectiveness, improved

operation efficiency and increased energy efficiency.

Read this chapter.

Chapter 3: Elements of a Direct Digital Control System

In this chapter:

Included in this section: data classification - type, flow and source: and characteristics of the software

supporting DDC systems.

Read this chapter.

Input/Output Tutorial

Purpose of this Guide:

This portion of Getting Started provides descriptions of input and output devices written for someone new to the

field or a seasoned engineer.

Chapter 1: Input/Output (I/O) Basics

10/14/2010 DDC-Online

ddc-online.org/Getting-Started.html 1

8/3/2019 DDC guide

2/2

In this chapter:

This section provides terms and definitions to help readers better understand material covered in next

chapters.

Read this chapter.

Chapter 2: Input Devices and Sensors

In this chapter:

In the world of HVAC control, there is basically one type of device used to complete a digital input (DI)

circuit. A switch, employed in various forms, is this device. The following sections outline common

switching devices currently used by the industry.

Read this chapter.

Chapter 3: Output Devices

In this chapter:

There are numerous analog devices used in the HVAC controls world. Typically, analog output devices are

used to provide modulating control of valves, dampers, electric motors through variable speed drives and a

wide variety of other devices. The most common devices associated with analog outputs are sequencers,

variable speed drives, silicon controlled rectifiers and actuators.

The section also reviews the most common devices associated with digital outputsrelays, contactors,

starters and two-position actuators.

Read this chapter.

Supported by the Iowa Energy Center.

http://energy.iastate.edu/

Copyright Iowa Energy Center.

10/14/2010 DDC-Online

ddc-online.org/Getting-Started.html 2