Mar 062013
 

This has been an unpublished firmware build for quite a while now, and we’ve finally had a moment to cut together a short video demonstration.

In summary, this firmware personality allows the DecaBox to

  • capture static DMX scenes (single frame snapshots)
  • … or dynamic looks (44 frames per second, with virtually no time limit),
  • … then replay this data using a simple RS232 command syntax
  • Also ‘build’ DMX scenes channel-by-channel using RS232 commands.

It’s been very popular with systems integrators who need more functionality than is provided by our RS232 to DMX engine.  Though the smaller DMX engine is fairly powerful, designers often have other DMX authoring tools they prefer to use, especially in situations involving complex cues and hundreds of channels.

The DecaBox allows DMX data to be captured from any system.  The data is stored internally on an SD memory card, and can easily be recalled.

The easiest way to demonstrate the different functions is with this quick video clip.  This clip covers capturing scenes using the front panel.  The serial syntax for capturing scenes is discussed below.

 

 

Command syntax is very straightforward.  RS232 connection is 9600 8N1.  If the DecaBox is connected directly to a PC, a crossover / null modem cable is required.

Here’s a screenshot from a terminal program, captured as the system boots up:

(Note that in this and all following screenshots, the image may be enlarged by clicking on it.  Also, yellow text is generated by the DecaBox and green text is sent to the DecaBox through the terminal program / Crestron system / etc.)  The text [cr] represents a carriage return character, decimal 13 or 0xod.

Splash Screen / RS232 Connection

Splash Screen / RS232 Connection

The system has two basic modes: DMX passthrough and DMX engine.  In DMX passthrough mode, data connected to the DecaBox’s DMX Input jack is copied to the DMX Output jack.  This feature is included because often an upstream DMX source, such as a lighting console, is used for primary control of the attached fixtures.  In this mode, the DecaBox is basically transparent to incoming data.  There is a latency of ~ 1 DMX packet, or 1/44 second, in passthrough mode.

In DMX engine mode, incoming DMX data is ignored.  The DecaBox generates all output data internally.

These two modes may be toggled between by sending P[cr] or E[cr].  At power up, the system defaults to E mode.

Engine / Passthrough mode

Engine / Passthrough mode

The DecaBox can grab static (one-shot) DMX scenes or record continuous sequences at 44 frames per second.

To grab a scene, send the serial command

GN[cr]

where

  • G is a capital G and mnemonic for grab
  • N is a decimal number, range is [1 999]
  • [cr] is the carriage return

Here’s a screenshot of the process.  Again, green commands are generated by the user, and yellow is feedback from the system.

Grab a single static frame.

Grab a single static frame.

To record a dynamic scene, with a time ranging from seconds to several hours, use this syntax:

RN[cr]

where

  • Ris a capital R and mnemonic for record
  • N is a decimal number, range is [1 999]
  • [cr] is a carriage return

The system creates the file for recording, and then prompts for a ‘start’ trigger.  B[cr] begins the capture and Q[cr] ends it, as shown below.

Record a dynamic DMX scene.

Record a dynamic DMX scene.

Once DMX data has been recorded, it’s useful to replay it.  To that end, both static scenes and dynamic recordings may be called through the serial port.

To play a static scene, the syntax is

SNNN:TTT[cr]

where

  • S is a capital S, and mnemonic for static.
  • NNN is a three digit decimal number, which matches a pre-captured scene
  • : is a colon
  • TTT is a crossfade time, in tenths of a second, between the current DMX output and what’s stored in the file
  • [cr] is a carriage return, decimal 13 or hex Ox0d

Here’s an example screen capture:

Replay a static scene.

Replay a static scene.

To recall a dynamic scene, use this syntax:

DNNN:RRR[cr]

where

  • D is a capital D and mnemonic for dynamic.
  • NNN is a pre-recorded scene number. three digits, with leading zeroes if needed.
  • : is a colon
  • RRR is the number of times a file repeats.  Use 000 for infinite loop.
  • [cr] is a carriage return.  Decimal 13 or 0x0D

Example:

repeatforever

Attempting to recall a scene which wasn’t previously stored in memory will return an error:

Error

Error

The command C[cr] can be used to instantly clear the DMX output.

Clear output.

Clear output.

If you need one of these, or something similar, please let us know!

 

 Posted by at 8:03 am

  One Response to “DecaBox DMX Recording and Playback”

  1. […] a long time we’ve been able to record incoming DMX to memory cards, then play it back on command.  So it didn’t take too much work to add MIDI […]

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