dmx-512a for led control: getting reacquainted with an old/new friend by shoshanna segal

Designers Lighting Forum

DMX-512A FOR LED CONTROL:Getting Reacquainted With an Old/New Friend

Shoshanna A. Segal, CLD, IALD, LEED APBD+CMarch 29, 2017

Credit(s) earned on completion of this course will be reported to AIA CES for AIA members. Certificates of Completion for both AIA members and non-AIA members are available upon request.

This course is registered with AIA CESfor continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any

material of construction or any method or manner ofhandling, using, distributing, or dealing in any material or product.___________________________________________Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.

LearningObjectives

1. Why a standards based system is a good idea

2. The basic organization and function of a DMX-512A System

3. How DMX-512A can be a useful tool in an architectural environment

4. Requirements and terminology for specifying DMX-512A system

At the end of the this course, participants will be able to:

Topics we will not cover today….Earl Simmons, American rapper, record producer, and actor

… or thisReebok’s proprietary foam compound used to provide cushioning and shock absorption in basketball shoes

WHAT IS IT?

• a method of digital data transmission between controllers and controlled lighting equipment and accessories, including dimmers and related equipment.

• intended to provide for interoperability at both communication and mechanical levels with controllers and receivers made by different manufacturers.

BASIC DEFINITIONS

• Original Title –• USITT DMX512 -

ASYNCHRONOUS SERIAL DIGITAL DATA TRANSMISSION STANDARD FOR CONTROLLING LIGHTING EQUIPMENT & ACCESSORIES – NOW

• ANSI E1.11-2008 (R2013) ENTERTAINMENT TECHNOLOGY

• USITT DMX512-A ASYNCHRONOUS SERIAL DIGITAL DATA TRANSMISSION STANDARD FOR CONTROLLING LIGHTING EQUIPMENT & ACCESSORIES

DMX512-ABUSDAISY CHAIN256512

BASIC HISTORY

• Developed in 1986 by USITT• Standard transferred to ESTA Technical

Standards in 1998

Why A Standard?

• Having a standard ensures that everyone using the specific technology is complying with the same set of rules. In this case that means…

Electrical Interface Standards• EIA485 (RS485)

Physical Interface Standards• 5-Pin XLR Connectors

Interface Standards• 8 pin modular or RJ45

Connectors

Topology Standards• MULTI-DROP BUS

TOPOLOGY WITH • DAISY CHANINED

NODES • ELECTRICAL

TERMINATION

BASIC DEFINITIONS

TOPOLOGY STANDARDS• An electrical scheme to carry power

or data• A bus can be Class I (Signal travels

with Line Voltage) • or Class II (Limited power, often 48V

or Less)• A bus can be rated (or limited) by

distance or cable length for signal/power – as in the 1500’ mentioned in the RP

• The rating of bus components affects the rated distance among or between components (nodes) for signal/power

• A bus can carry Digital or Analog Communication

DMX-512-A

BUSDAISY CHAIN256512

BASIC DEFINITIONSDMX-512-ABUS

DAISY CHAIN256512

TOPOLOGY STANDARDS

TOPOLOGY STANDARDS

THIS

NOT THIS

BASIC DEFINITIONS

• DMX-512-A breaks down the control process into 256 digital steps.DMX512-A

BUSDAISY CHAIN

256512

BASIC DEFINITIONS

• 512 REPRESENTS THE MAXIMUM NUMBER OF ADDRESSES OR DATA SLOTS AVAILABLE WITHIN ANY SINGLE DMX512 UNIVERSE

• EACH OF THE 32 NODES ON THE BUS CAN BE INDIVIDUALLY CONTROLLED BY SENDING INSTRUCTIONS TO EACH OF 16 ATTRIBUTES.

• 32 x 16 = 512

DMX512-ABUSDAISY CHAIN256

512

How is all of this used?

Lighting Control ComponentsAll lighting systems have essentially the same components:• User-Command/Sensor/Controller/

Dimmer/Switch• Interface - translates signal to

action• Power• Regulator-

Driver/Ballast/Transformer• Light Source/Luminaire/Light

Engine

How do we communicate with the light source?

0-10V

PHASE CONTROL

PWM

0-10v systems

• Line voltage switches the driver “on”

• Low voltage provides a control signal indicating a percentage of maximum output

• Voltage drop is an issue as the control signal is weakened as it travels

• May result in output differences along a single control run

• 0-10v is an analog control protocol and it interfaces with the LED Driver with 2 sets of wires

• Class I 120/277 line-voltage switching

• Class II ≤48v dimming control

ANSI C82.11 vs. ESTA E1.3

ANSI C82.11• CURRENT SINK• DRIVER PROVIDES CONTROL

VOLTAGE• DIMMER IS PART OF DRIVER• MAX OUTPUT AT ≥10V• MINIMUM OUTPUT AT 1V• MAY REQUIRE ADDITIONAL

“OFF”• MAX # OF DRIVERS/CONTROL

LIMITED BY DRIVER CAPACITY

ESTA E1.3• CURRENT SOURCE• CONTROL PROVIDES VOLTAGE

FOR EACH CHANNEL• DIMMERS ARE SEPARATE FROM • MAX OUTPUT AT 10V• OFF AT 0V

Phase Control Systems

• Modulates the amount of time full voltage is applied

• 120 times per second

• 2x frequency is delivered via AC (60Hz)

Forward Phase

Also called Leading Edge

Reverse PhaseAlso called Trailing Edge

Pulse Width Modulation• Controls the time-averaged

current through an LED and therefore the intensity.

• LED is turned on and off more quickly than is perceptible to the human eye. The intensity is approximately proportional to the percentage of time that the LED is on.

• Because it can control individual LED’s PWM can be used for color mixing as the relative levels of each component color can be manipulated to achieve the desired color.

Why these are non issues with DMX512-A?

DMX-512A

PROS• Stable protocol designed to

make products from different manufacturers work together; refined and reapproved for over 30 yrs.

CONS• “Old Technology”

DMX-512A

PROS• Stable protocol designed to make

products from different manufacturers work together

• Less gray area than other methods – presence of a written standard means you either comply or don’t


• Requires “special” equipment

DMX-512A



• Less gray area than other methods –presence of a written standard means you either comply or don’t

• Technology designed for mission critical live performance



• Not every conference room needs this

DMX-512A





• “Old school” nature of the standard means relatively few places to look when problems do arise




• No inherent error checking, communication is unidirectional

DMX-512A





• “Old school” nature of the standard means relatively few places to look when problems do arise

• Wireless DMX




• No inherent error checking, communication is unidirectional

• “But I want wireless”

This concludes The American Institute of Architects Continuing Education Systems Course