Advanced DMX Networking

Transcription

1 Advanced DMX Networking Presented by IATSE Local 728 Training Program April 28, 2007

2 History of DMX512 USITT DMX512 A Digital Data Transmission Protocol originally intended for dimmers and controllers that operates on an EIA-485 electrical network; DMX512 & DMX512/1990 also specify connectors & cable Before DMX512 Multiple Protocols, Different Control Voltages, Incompatible with each other CD80 (AMX192), K96, CMX, and others Need for Lowest Common Denominator a way any Controller could operate any Receiver USITT responded in 1986; minor revision in 1990

3 History of DMX512 Updated & became an ANSI standard in 2004 ANSI E , Entertainment Technology USITT DMX512-A Asynchronous Serial Digital Data Transmission Standard for Controlling Lighting Equipment and Accessories Made editorial updates to DMX512 as appropriate Added technical features while maintaining a balance with backward compatibility Cable broken out to different standards: E , Portable Cables BSR E1.27-2, Permanently Installed Cables (about to go out for Public Review)

4 Requirements of DMX512 Required cable is EIA-485 (RS-485) Twisted Pair w/ Overall Shield; 120 Ω Nominal. 2-Pair Cable Required for some manufacturers and to be required in the wall in new DMX512 cabling standard EIA-422 (RS-422) also used and normally works Twisted Pair w/ Overall Shield; 100 Ω Nominal Possibility of problems in long runs due to mismatch of impedance of cable (100 Ω) to electronics (120 Ω) Category 5 UTP Cable acceptable Can provide an upgrade path to Ethernet if cable plan is properly implemented

5 DMX512 Terms Universe Slot (Address) Isolation & Grounding Break Splitter, Amplifier Merger Termination

6 Requirements of DMX512 EIA-485 requires point-to-point Daisy-Chain cabling between devices with Line Termination Maximum of 32 Unit Loads on a Daisy-Chain Star Topology not permitted (no Y s, stubs, or branches) Use Repeaters or Splitters if the number of devices is high and/or a Daisy-Chain installation is not practical The 5-Pin XLR connector is the ONLY Connector ever allowed by DMX512 3-Pin XLR and RJ-45 Connectors are NOT allowed (exceptions for RJ-45 in E1.11)

7 RDM RDM - Remote Device Management (ANSI E ) Extension of DMX512-A An enhancement to USITT DMX512 for configuration, status monitoring, and management of DMX512 based systems Extends two way communication out to the end of DMX512 data link. ACN works over Ethernet, RDM works over DMX512

8 Common Causes of DMX512 Problems Splices / Bad Terminations Wrong or Mismatched Cables Cross-Wiring Cables mixed in with Power Wiring Drain Wire and/or Shield Exposed Incompatible Equipment Different use of 2nd Pair Bad Equipment Grounds

9 Wireless DMX512 No standard or cross-manufacturer compatibility Most use Digital Spread Spectrum Technology DSSS - Direct Sequence Spread Spectrum FHSS Frequency Hopping Spread Spectrum Some implement proprietary versions of the above Most 2.4 GHz (also 900 MHz & 5.8 GHz) Wi-Fi (802.11) is more susceptible to interference Propagation Delay - Most often not a problem Bi-directional - Not all systems are capable, therefore may not be able to do RDMl

10 Hexadecimal System DMX is based on a Hexadecimal 16 bit system which is converted into a percentage display = 1-100

11 Advanced DMX for the Set Lighting Technician Test Equipment Transmit/Receive DMX Cable test Should be easy to read Analyze DMX signal Operation should be intuitive

12 Advanced DMX for the Set Lighting Technician Control Network Advanced Control networks include combinations of DMX and Ethernet components.

13 Four Groups Group 1 - Control

14 Four Groups Group 2 - Network

15 Four Groups Group 3 - DMX Devices

16 Advanced DMX for the Set Lighting Technician Four Groups Group 4 - Metering & Testing