WF AUTOMACAO wrote: > > OPPPS, > > I put in one of my Last e-mail: DXF Protocol! > > Sorry, my friend is looking for DMX512 protocol! Sorry again! > > Thanks if someone know where find information about! > > :( > > Miguel. Here's the standard. :) Cheers, -- ~Keith tsk3000@Prodigy.Net http://pages.prodigy.net/tsk3000/ United States Institute for Theatre Technology, Inc. ==================================================== U S I T T ==================================================== DMX512/1990 DIGITAL DATA TRANSMISSION STANDARD FOR DIMMERS AND CONTROLLERS ____________________________________________________ APRIL 1990 A Revision of the DMX512 Standard Published in August 1986 A Project of the USITT Engineering Commission U S I T T 10 W. 19th St. - Suite 5A New York, NY 10011-4206 (212) 924-9088 (212) 924-9343 FAX DMX512/1990 Digital Data Transmission 1.0 SCOPE This Standard describes a method of digital data transmission between controller s and dimmers. It covers electrical characteristics, data format, data protocol, connector type, and cable type. 2.0 APPLICABILITY This Standard is intended as a guide for: 1. Equipment manufacturers and system specifiers who wish to integrate systems o f dimmers and controllers made by different manufacturers. 2. Equipment manufacturers seeking to adopt a standard controller-dimmer digital transmission protocol. Although widespread adoption of this standard is sought by USITT, compliance wit h the standard is strictly voluntary. Furthermore, it is not intended as a replacement for existing protocols already manufactured, but rather as an additi on to existing protocols which will broaden the installed base of controllers and dimmers that can communicate with each other. 3.0 CROSS REFERENCE See EIA standards EIA-422A and EIA-485 available from: Electronic Industries Association Standards Sales Office 2001 Eye Street NW Washington, D.C. 2006 202-457-4900 4.0 ELECTRICAL SPECIFICATIONS This standard shall follow EIA Standard EIA-485 (an enhanced version of EIA-422A ) with regard to all electrical characteristics including line driver and receiver selection, line loading, and multi-drop configurations. 4.1 COMMON MODE VOLTAGES Equipment designers are advised to pay particular attention to the Common Mode voltage provisions of EIA-485 in the choice of transmitter and receiver componen ts and general system implementation. 4.2 ELECTRICAL ISOLATION This standard and EIA-485 make no general provisions for electrical isolation. However, suitable optical isolation, transformer isolation, or other means may b e employed to prevent the undesirable propagation of voltages which exceed the Com mon Mode limits of EIA-485. The inclusion of such isolation does not, however, alte r the requirement that a transmitter or receiver conform to EIA-485. DMX512/1990 - 1 - April 1990 5.0 DATA PROTOCOL Data transmitted shall be in asynchronous serial format. Dimmer level data shal l be transmitted sequentially, beginning with dimmer 1 and ending with the last implemented dimmer, up to a maximum of 512. Prior to the first level transmitte d, a RESET signal shall be transmitted followed by a NULL START code. Valid dimmer levels shall be 0 to 255 decimal (00 to FF hexadecimal) representing dimmer cont rol input levels of OFF to FULL in a linear relationship. These numeric values shal l not necessarily have any relationship to actual dimmer output, which shall be determined within the dimmer itself. 5.0.1 RESET SIGNAL The RESET signal (Timing Diagram, Designation #1) shall consist of a BREAK lasti ng 88 uSeconds (two frame times) or any longer duration. A BREAK shall be defined as a high-to-low transition followed by a low of at least 88 uSeconds. All dimmers a nd other receiving devices shall interpret any such BREAK as a terminator for any pending transmission/data packet and its end as the start of the MARK AFTER BREA K and START code sequence at the beginning of the next packet. 5.0.1.1 MARK AFTER BREAK The duration of the MARK seperating the RESET/BREAK and the START code (Timing Diagram, Designation #2) shall be not less than 8 uSeconds and not greater than 1 Second. All DMX512/1990 transmitters shall produce a MARK AFTER BREAK of not le ss than 8 uSeconds. All receivers shall recognize an 8 uSecond MARK AFTER BREAK. Receivers capable of also recognizing the shorter 4 uSecond MARK AFTER BREAK (as specified in the 1986 DMX512 Standard) may be identified and marked as having th is capability as per paragraph 11.0 5.0.2 NULL START CODE The NULL START code shall be defined as a properly framed NULL character (all ze ros) following a RESET. The NULL START identifies subsequent data as sequential 8-bi t dimmer level information. 5.0.3 OTHER OPTIONAL START CODES In order to provide for future expansion and flexibility, this Standard makes provision for 255 additional START codes (1 through 255 decimal, 01 through FF hexadecimal). For this reason, a dimmer receiver must not accept as 8-bit level data any data packet with a START code other than NULL START following the RESET . 5.0.4 MAXIMUM NUMBER OF DIMMERS Each data link shall support up to 512 dimmers. Multiple links shall be used wh ere larger numbers of dimmers are required. DMX512/1990 - 2 - April 1990 5.0.5 MINIMUM NUMBER OF DIMMERS There shall be no minimum number of dimmers on the data link. DMX512 data packe ts with levels for less than 512 dimmers may be transmitted, provided that the conditions of this Standard, including Paragraphs 5.0 through 5.0.8, are observe d. 5.0.6 DEFINED LINE STATE BETWEEN FRAMES The time between any two frames of a data packet (Timing Diagram, Designation #8 ) may vary between 0 uSeconds and 1 Second. The line must remain in a "marking" s tate during any such idle period greater than 0 uSeconds. A receiver must be capable of accepting a data packet having no idle time (0 uSeconds) between any of its fram es. 5.0.7 DEFINED LINE STATE BETWEEN DATA PACKETS Every data packet transmitted on the data link, regardless of START code or leng th, must begin with a RESET, MARK AFTER BREAK, and START code sequence as defined ab ove. The time between the second stop bit of the last data byte/frame of one data pac ket and the falling edge of the beginning of the RESET for the next data packet (Tim ing Diagram, Designation #9) may vary between 0 uSeconds and 1 Second. The line mus t remain in an idle ("marking") state throughout any such period greater than 0 uSeconds. Transmitters, therefore, must not produce multiple BREAKs between d ata packets. Receivers, however, must be capable of recovering from multiple BREAKs produced by data link errors. 5.0.8 MINIMUM BREAK SPACING The period between the falling edge at the start of any one BREAK shall be not l ess than 1196 uSeconds from the falling edge at the start of the next BREAK. 6.0 DATA FORMAT The data transmission format for each level transmitted shall be as follows: BIT POSITION DESCRIPTION 1 Start Bit, Low or SPACE 2 through 9 Dimmer level Data bits, Least Significant Bit to Most Significant Bit Positive logic 10, 11 Stop Bits, High or MARK Parity Not transmitted 7.0 DATA RATE The data rate and associated timing shall be as follows: Data Rate 250 Kilobits per second Bit Time 4.0 uSeconds Frame Time 44.0 uSeconds Maximum Update Time for 512 dimmers 22.67 milliseconds Maximum Update Rate for 512 dimmers 44.11 times per second DMX512/1990 - 3 - April 1990 7.1 TIMING DIAGRAM See Figure 1 for the DMX512/1990 timing diagram. Figure 1 8.0 LOSS OF DATA TOLERANCE The receiving device must maintain, for a minimum of 1 Second, the last valid le vel received for each connected dimmer. Designers of transmitters are reminded that a low number of dimmer level (START CODE 00) updates may be interpreted by a recei ver as a loss of data. 8.1 RECEIVER DATA RATE TOLERANCE DMX512/1990 is intended to make possible the interconnection of lighting control equipment by different manufacturers. It does not specify the minimum performan ce levels of connected equipment, either by requiring a minimum number of level upd ates per second be produced by a transmitter, or by requiring that all level updates on the data link be used by the receiver. The performance of any device incorporating a DMX512/1990 receiver must, however , not be degraded by the presence at its input of the continuous transmission of d ata packets containing any number of dimmer levels up to the maximum update rates specified in Section 5 and Paragraph 7.0 above. DMX512/1990 - 4 - April 1990 9.0 CONNECTORS Where connectors are used, the data link shall utilize 5-pin "XLR" style microph one connectors. Some manufacturers of this connector are: Switchcraft ITT Cannon Neutrik 9.0.1 CONNECTOR SEX Female connectors shall be utilized on controllers or other transmitting devices and male connectors shall be utilized on dimmers and other receiving devices. In ca ses where an optional second data link is implemented using the spare pins of the connector for bi-directional transmission, female connectors shall still be util ized on the controller. 9.0.2 CONNECTOR PIN DESIGNATION Connector Pin Designations shall be as follows: PIN 1 - Signal Common (Shield) PIN 2 - Dimmer Drive Complement (Data 1 -) PIN 3 - Dimmer Drive True (Data 1 +) PIN 4 - Optional Second Data Link Complement (Data 2 -) PIN 5 - Optional Second Data Link True (Data 2 +) 10.0 CABLE Cable shall be shielded twisted pair approved for EIA-422/EIA-485 use. Examples of suitable cables are: Belden 9841 Alpha 5271 (one pair, no spares provided) Belden 9842 Alpha 5272 (two pairs, one as a spare) 11.0 MARKING AND IDENTIFICATION Equipment conforming to this Standard may be marked and identified with "USITT DMX512/1990" or "DMX512/1990". Only receivers also capable of accepting a 4 uSecond MARK AFTER BREAK may be mar ked and identified as "USITT DMX512/1990 (4uSec)" or "DMX512/1990 (4uSec)". Compliance with this Standard is the responsibility of the manufacturer, and suc h marking and identification does not constitute certification or approval by the USITT. = END = DMX512/1990 - 5 - April 1990 This page contained a diagram refered to as fig 1 in text, here reproduced in A SCII |<---------------------------"PACKET"------------------------------------>| | | | |<------"FRAME"------>||<------"FRAME"------>||<------"FRAME"------>| | |<---------3--------->||<---------3--------->||<---------3--------->| |-1-| |4| |7| ||4| |7| ||4| |7| | |9| |2| |5| |6| |7|| |5| |6| |7|| |5| |6| |7|-9| -1| __v v_v v_v_ _ _ _ _ _v_v____v v_v_ _ _ _ _ _v_v____v v_v_ _ _ _ _ _v_v______v v | | | | | | | | | | | | | || | | | | | | | | | | || | | | | | | | | | | | | | | | | | | | | | | | | | | || | | | | | | | | | | || | | | | | | | | | | | | | | | | | | | | | | | | | | || | | | | | | | | | | || | | | | | | | | | | | | | ^ | | | | | | | | | | | | | || | | | | | | | | | | || | | | | | | | | | | |^ | | | |___| |_|_|_|_|_|_|_|_|_| | ||_|_|_|_|_|_|_|_|_| | ||_|_|_|_|_|_|_|_|_| | || | __| | / / | | BREAK START CODE (8) DIMMER 1 (8) DIMMER N |BR EAK | OR | OR | RESET |RE SET | | IDLE IDL E LINE LIN E "MARK" "MAR K" DESIG DESCRIPTION MIN TYP MAX UNIT 1 "SPACE" FOR BREAK 88 88 uSEC 2 "MARK" BETWEEN BREAK 8.00 - uSEC & START CODE - 1.00 SEC 3 FRAME TIME 43.12 44.0 44.48 uSEC 4 START BIT 3.92 4.0 4.08 uSEC 5 LEAST SIGNIFICANT DATA BIT 3.92 4.0 4.08 uSEC 6 MOST SIGNIFICANT DATA BIT 3.92 4.0 4.08 uSEC 7 STOP BIT 3.92 4.0 4.08 uSEC 8 "MARK" TIME BETWEEN FRAMES 0 0 1.00 SEC 9 "MARK" TIME BETWEEN PACKETS 0 - 1.00 SEC ------------------------------------------------------------------------------- This document was keyed by hand on 6 February 1992 from the original standard obtained from USITT in mid january 1992. Neither I nor any parties involved in the transmission of this document to you can accept any responsibility for errors, and you use it at your own risk. There was no copyright notice on the original document. I have attempted to follow style as much as possible. Following the style has meant that some of the lines are 84 columns long - sorry! It has been necessary to substitue u for 'mu'. Occurances of "uSecond", "uSec" and "uSEC" in the text are references to microsecond, one millionth of a second. I noted one item that I think is in error in the standard. I have copied this item into this document and have not corrected it. I believe that the item given under "7.0 DATA RATE" as "Maximum Update Time for 512 dimmers" should in fact read "Minimum Update Time for 512 dimmers". A proper copy of this standard is available from USITT for nominal cost. The paper document includes a clear diagram for "Figure 1" and the AMX192 standard. USITT will also be able to provide you with the latest revision when DMX512/1990 is superseded. -------------------------------------------------------------------- Steven Murray stevenm@zeta.org.au PO Box 1491, North Sydney The paper burns, but the words fly away. NSW 2060, Australia. - Ben Joseph Akiba