The Rack Mount Multi-Out DMX Engine

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Jan 082019

We were contacted by an integrator whose DMX fixture installation was large and complicated. They were using a Control4 system and chose our RS-232 DMX Engine as the master output controller in their system. However, in their case the standard practice of daisy-chaining large groups of fixtures* together was impossible, due to the required physical layout, access to connected conduit, etc.

During a telephone consultation, we discussed installing multiple DMX Engines throughout their venue. Because of the required layout, this would have been quite expensive. When we learned that their timeline was fairly relaxed, it made sense to commission a rack-mount system with 12 outputs, 12 isolated output drivers, and genuine Neutrik EtherCON jacks for easy termination of their installed wiring. Our friendly metal shop across town returned two pair of blue-anodized chassis sets a few weeks later:

Click to Enlarge
Click to Enlarge

The system follows the now-standard pinout for DMX over CAT5 cable. We use the DATA 1 pair (orange) with both brown conductors grounded:

CAT5 cables wired to the 568-B standard can carry DMX data

This rack-mount DMX Engine functions exactly the same as its smaller red brethren. The command set is identical; only the form factor and output count have changed. Need one? Let us know.

*This was the subject of a tech support call earlier in the week. When playing in the DMX world, there are two numbers to keep track of: channel count and fixture count.

Channel count is fairly obvious: a full universe of DMX contains 512 separate channels. This means that 512 single AC dimmers could drive 512 discretely connected incandescent light bulbs. When the author got started in technical theatre, the entire venue was controlled by large, dusty, hum-emitting 6 KW dimmers. About 30 worked properly. The command ‘set all to full time zero’ provoked a physical, visceral reaction from offstage left.

If using RGB LED fixtures, a universe can discretely control 512 / 3 = 170 fixtures without any overlap. Some modern moving lights à la rock concert gobble up 100+ channels each, which means only five can be individually driven on a single universe.

Recently, we completed a Christmas art installation where a single tree required nearly 23,000 channels of data running at 50 frames per second. We used e1.31 / sACN (DMX over ethernet, more or less) as the control backbone.

Fixture count is a different beast altogether. It relates to the total electrical load on the differential bus (D+ and D-, the DMX data signals). Each fixture connected in a daisy chain increases the load, and if it’s too high, signaling can turn erratic and be difficult to troubleshoot. Here’s a great article which dives deeper into the math. In any case, the ‘standard’ load for an RS-485 receiver (and by extension, a connected DMX device) is 1/32, which means that 32 devices can be safely daisy-chained together and driven successfully by a single master controller. If fixture load isn’t explicitly called out in a device’s datasheet or instruction manual, assume 1/32 load.

For slightly more money, some manufacturers (including us, as has been required by clients from time to time) design DMX input stages with 1/256 load receivers, which allows up to 256 devices in a single daisy chain without introducing signal issues.

Bottom line: make sure both your channel count and fixture count are within acceptable ranges. If fixture count is too high, consider using what’s called an optosplitter, which receives a signal and then regenerates it multiple times across multiple outputs. Or call us and we can help with something custom.

The Ethernet DMX Engine

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Feb 262018

It’s finally (almost) here.  We’re planning a release date in early Q2 2018.  The Ethernet DMX Engine will feature a nearly identical command set as our current RS-232 version.

As we make final decisions regarding the panel layout and connections, we’d love your feedback.  Please take a few seconds and visit this very short survey:

Features – The Ethernet DMX Engine

 Posted by at 7:33 pm

New Tools

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Feb 172014

As a bit of an accounting exercise, we totaled up the money we’d been spending to outsource laser-cut materials (LCD chassis windows, plus small acrylic chassis sets for quick-turn work mostly) as well as chassis labeling and printing.  Though our outside vendors did great work, it was common for our three hour job to sit in their queue for 2-3 weeks before it was completed.

Not terribly efficient.

So in Mid-January, we purchased an 80-watt laser cutter with a 400 x 600 mm working space and an adjustable z-axis which travels up to 250 mm.  It’s been a wonderful addition to the shop.  It’s been used so far to mark a production run of DecaBox chassis pieces:

DecaBox - Laser Etched

DecaBox – Laser Etched


Close View


… with lovely results.  We also marked and branded a batch of complicated chassis sets which we OEM for another customer.

Last week, we were asked to ship a very quick-turn LED driver system, complete with protective chassis.  In the space of three hours, we hopped from napkin sketch to CAD drawing to paper printout to laser-cut cardboard mockup (several iterations) to final chassis cutting.  The flexibility and precision of the process is very rewarding.  Many many revisions can be completed in-house, in less time than it would take to visit a cross-town vendor.

Testing - Front Panel Design

Testing – Front Panel Design

A bespoke power supply + DMX receiver + LED pixel strip driver

A bespoke power supply + DMX receiver + LED pixel strip driver

A good friend who works as a lighting designer most nights – but who also plays in a band – received a copy of the group’s logo etched in 1/2″ water clear acrylic.  A black background and edge lighting make a beautiful result.


13″ square, 1/2″ acrylic

The money we would have spent to outsource this work, just over the past two weeks, totals about 10% of the machine’s cost.  That’s not such a bad return.

We look forward to helping our customers with high-quality, well-designed and quick-turnaround designs this year.


 Posted by at 10:54 pm

RS232 DMX Engine – New Firmware

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Jan 032014

Click to Enlarge

Happy New Year!

We’re pleased to announce a release of v4.7 firmware for the RS232 DMX Engine.  It’s a free update for all existing customers, and will ship installed on any purchase made after January 3, 2014.

Full details are available on this page, but here’s a quick breakdown of the added features:

  • Add ‘streaming data’ command.  It’s now possible to write to the repeating DMX output stage directly from your RS232 port, with almost zero protocol overhead.
  • Added command for initiating a hardware reboot.  Emulates a power cycle.
  • Added  command to pause crossfading mid-transition.
  • Added command for jogging individual channels up or down by a specified amount.
  • Add scene recall masking.  This makes it possible to recall a stored scene, but only apply it to specific DMX channels.  This is useful for multi-room installations, etc, where one room’s look should change without disturbing other presets.

If you’d like to update your existing equipment, just contact us for the details.  The process takes about 10 seconds to complete in the field.

Finally, if you’re interested in receiving email updates when new firmware for any of our equipment is released, or when new products become available, just enter your name and email address in the top right corner of this screen.

 Posted by at 11:06 pm

Ex-Rental Stock – Flapper MKIIs

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Apr 242013

Check out the bargain bucket – we’ve got five Flapper MKII projector shutter systems, recently returned from long term rentals.  Though there might be a few cosmetic scuffs, the gear works perfectly.  Now’s your chance to grab a projector shutter at much-less-than-regular price.

 Posted by at 2:14 pm