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DMX512 with 'HMS Protocol'

     HMS-RS232-DMX-AH96 
HMS-RS232-DMX-AH96 Board

Text Mode (Ascii) DMX Controller

HMS Firmware Protocol DMX512 Controller

Features:

Description of Operation:
This board is used to interface to any BrightSign with an RS232 port or any RS232 device (5 volt Jack required if non BrightSign use)

Serial Transmission 'Break' Protocol:  The RS232 port (BrightSign) has to allow 20 milliseconds to elapse between serial data 'bursts' going out.  This 20 millisecond 'rest' time is interpreted by the HMS board as a 'Break' in serial transmission.  This 'Break' condition synchronizes the HMS board to the serial transmissions from the BrightSign (or other device).

New Command Selection for HMS Protocol:  The first byte received by the HMS board (after 'break condition') sets the receive protocol command.  This new protocol simplifies how many bytes to send from the BrightSign because the DMX parameter is selectable! The bytes are enclosed in brackets [ ].  Note: 'Speed' = Rate of Fade.

Note: See the 'Not HMS Protocol' for simple DMX control (no fade) near the bottom of this specification sheet.

Ascii (Text) Mode:
This controller uses Ascii or 'Text' strings.  All the commands should be sent as text.  A space or comma separates bytes.  A carriage return ends the command string.
I.E. to send command 22 you send  "22 1 255" or "22,1,255" (note: leading zeroes are discarded.  "001" = "1")

*********Play/Record and Other 'Scene' Commands 32-36

Link to 'Scene Format (Protocol)'

********Miscellaneous Commands (Useful for Development)

Note: Use you computer to send these commands so that you can view the data

*1: 'End Command' means that this was the end of the command and another command can be part of the same string (no 'Break' required) 
I.E. Turn on DMX channel 1 100%, Turn on DMX channel 50 100%   [22,1,255,22,50,255]  (Two command22's in succession)

Notes:

To Send Multiple Commands (not concatenated) , Send 1 command, then pause for 10 milliseconds, then send the next command and pause and so on except where designated above.
I.E. if selecting Command12 (Set all 16 DMX fade values): Note if all 16 values are sent then the next Command can be part of the string.
I.E.  [15,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,'new Command#','bytes for that Command]

Note: Fast Flash of the 1Hz LED (3 Hz).  When any command is terminated with 'Break', fast flashing occurs.  When a command is sent incomplete or out of range, (I.E. set fade for channel 30), because channel 30 is out of range, fast flashing is set.  Fast Flashing is cleared upon complete reception of a command not requiring the 'Break' condition.  I.E. Send 'Command0', to clear the fast flashing after 'Break'.

DMX512 Operation:  The DMX first 4 to 'Max Channels' channels (see command31) are sent every .8 seconds if Option2) or whenever the DMX 'Channel' bytes change (resulting in instant DMX output).  The DMX512 protocol is so fast that the entire 256 (256 channels) channels of DMX data can be sent out during 12 milliseconds.

DMX 'Head' Operation.  If a DMX dimmer pack is utilized, setup the dimmer pack to utilize channels 1-4.  Then set the DMX 'Head' start channel to 5 (or whatever channel is allowed).  If the DMX 'Head' is the only DMX device, then set the 'Head' channel to channel 1.  If the DMX 'Head' protocol expects to receive 20 bytes (20 channels) then all 20 of those bytes need to be sent with each DMX 'Head' command sequence.  Likewise, when using the BrightSign to control the DMX Head, the BrightSign should send all 20 DMX bytes with each Serial Send() command. If the DMX512 'Head' can only be set for 'even addresses' or multiples of a number (I.E. 20,40,60) then the bytes for that address (channel) will have to start at the address or channel set as the base channel.

DMX 'Play Scenes'.  A 'scene' file can be created and stored on the SD card.  BrightScript would be used to interpret the 'scene file'.  Any number of scenes could be stored on the SD card.  Contact the BrightSign people if you need help with this programming.

Diskette DMX_Demo.AVI (84 mega byte movie demo)                  Diskette  DMX_Demo.mov 6MB (requires Quicktime)    Link: Setting up the Serial Port and Sending Bytes with 'BrightAuthor'.

 

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Options:

Not HMS Protocol:

With Option 1 on (SW1-1) the HMS Protocol is not used.  Instead, a simple protocol is used and no Fade!  This protocol is that you first send 0xAA (decimal 170) followed by the bytes for DMX channels 1 thru ??.

 

Note: Fade Command makes 'Fading the lights on and off' an easy task if utilizing a DMX Dimmer Pack.  To Fade up lights just output 0xFF ( 255 decimal) for the channel value for DMX Ch 1 to 24)  To Fade down the lights, just output a zero (decimal) for the channel value and the brightness will Fade down at 20 millisecond intervals or at the rate specified with the speed setting.

Note: Fade Speed: The Fade speed value is the number of milliseconds to increment (increase brightness by '1') or decrement (decrease brightness by '1') of the channel value.  If the channel value is 255, and the speed value=20, then it takes 20 milliseconds for each step or 5.1 seconds to obtain full brightness (0 to 255).  If the Fade Speed is zero, the new channel value is output immediately to the DMX channel.  So if the channel value was 0, then 255 and the speed value is 255 (255 milliseconds per step of 1),  then it will take 65535 milliseconds (255 times 255) to finish Fade (1092 seconds).  You may want to keep the value below 50.

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Note: External Supply Voltage:  External 5 volts is necessary if not using a BrightSign.  The BrightSign supplies 5 volts via pin4 of the DB9 Connector.

Page Updated 03/02/2024