September, 2006 Technopolis

One From Column A, Two From Column B

Moving Light Menus, and something new under the sun!

I have a confession to make. I snuck into the TV studio at school the other day and stole their lighting controller. It was summer, so they weren’t actually using it, and I wanted to fiddle with a new moving light I received that morning. I needed a nice, small DMX512 controller and they had one. I carried the thing down to our theater, set everything up in our orchestra pit and began to put my new light through its paces.

In particular I wanted to fiddle with the menu controls. All of the latest intelligent lighting fixtures have an incredible (let’s be honest, overwhelming) number of menu options and settings, with extra features being added every day. You can change the menu settings without a controller (right there at the light), but having a controller next to the thing makes it easier to see the results. It was also kind of fun to play with the sliders and watch my new toy spin around and around right in front of my eyes… but, hey, I’m easily impressed.

Appetizers

I suppose the most important menu setting would be the DMX address itself. How many of us have struggled with an erratic unit only to find that the address was set incorrectly? This happens a lot when we have to take a unit out of service and hook up a new one. Somewhere during the swap the correct DMX address gets forgotten. Push a few buttons, problem solved. (At our school installation we have a piece of white gaff stuck on every DMX connector with the “proper” DMX address written right on it. Yes, I realize that this is cheating.)

For today’s experiment I went way out on a limb and assigned my new light the DMX address of, um… one. Actually “001,” which is also the default address for most units (and the address that corresponds with the “slave” setting when lights are strung together without a controller nearby). Of course, this actually assigned my first sixteen addresses, since my new light has sixteen controllable features. And, to get back on-topic, almost all of these features can be changed in the menu.

Salads (The menu is trying to tell you something…)

When I turned on the controller the menu on my light very kindly stopped blinking at me, an indication that the DMX was working. I also got a somewhat cryptic indication that the lamp was on and functioning correctly. Knowing these subtle indications (in this case, a lit decimal point) can save a lot of hunting around when things aren’t right. Plinking through the menu I found the TEST function, and the LAMP ON/OFF, both very useful, as you might imagine. Other standard menu options were RESET, TIME and DISPLAY. RESET is sort of like a warm re-boot on a computer, re-aligning all the filters and gobos, which sometimes get out of adjustment. TIME tells you how old the lamp is so you can replace it before it blows, DISPLAY allows you to turn the menu display off so it won’t annoy your audience.

Some of the other menu items are a little more esoteric. Suppose we have a dozen similar units, half of which are hanging upside down above the talent. Change the RPAN and RTLT in the menu and all of the units will track together left-to-right and up-and-down. RPAN also comes in handy when units face each other, you can set one side to mirror the other, greatly simplifying the cues. There’s also a DISP/FLIP setting so that the now upside-down menus can be set to read correctly. Why bother? Any trick to save a little trouble further down the line is worth it.

All we have to do is step through the menu until the menu option we want appears on the display, then activate or deactivate the setting. Of course the display characters and features are different for different manufacturers, but if you can figure out text messages (U KN 2 THT, RT?) you can figure out the menu abbreviations. For instance, many lights allow you to turn off two or more features ,typically the fine pan and tilt (menu option FINE or FNE or FN, whatever).<<<< This can save you a couple of DMX addresses, and perhaps help you program two dissimilar units more easily.  (R – is this right?? - J)>>>>

You want that to go?

Imagine discovering an incorrect DMX assignment on a somewhat inaccessible unit. Never happens in real life, but hey, let’s pretend. This intelligent light allows you to reassign the DMX address from the board. The menu setting is RDMX , and, as far as I know, only this light has this exact feature. It’s a little tricky until you’ve done it a few times; I freely admit I have to step through it with the manual open right next to me. Setting several channel controllers just so sends a DMX assignment change to the distant unit. After 20 seconds the DMX assignment is fixed. You do have to know the “bad” DMX assignment, the one you want to change. Details? You want details, I got details, Set channel one and two to 03 (007 on your more fancy boards), set channel three to the new DMX assignment. Important little note (not in the manual)… set all the other channels to zero. You can believe me that little piece of info was hard to come by… all 16 “bad” DMX channels have to be be set properly for this new trick to work… even if you turned off the FINE mode  (14 channel mode, see above).  It’s theoretically possible to call this function up by accident, which is why you can turn the RDMX option off at the menu if you wish.

Small or Large?

The unit I was experimenting with also had an option (menu accessible) to change the pan limits from 630 degrees, which is more than some other units, to 540 degrees, which is a little more standard. Imagine the difficulty of interpolating the differing settings when mixing these lights with older stock and you will appreciate the menu tweak. Most manufacturers have a special feature or two like this that needs menu access; look for them in the online manuals. This is probably not the right time to tease the manufacturers about the poorly written manuals (Hey… I know a good writer), but, yes, the manuals could be a little more helpful (see above). As I’ve said before, stare at the manual (and the menu) long enough and it will eventually make sense.

I still have to return the lighting controller to the TV studio, but not before I play with the rest of the menu options on my light. I’ll tell you about it next month. As my students say, “Mad props!” to Eric and Ray over at Elation Lighting for providing the test unit, the new Design Spot 250.

John Kaluta teaches Research & Experimentation and Robotics at Montgomery Blair High School in Silver Spring, MD. He is also the author of The Perfect Stage Crew, The Compleat Technical Guide for High School, College, and Community Theatre, available at the PLSN Bookshelf. And, yes, he returned the TV studio lighting controller to the TV studio.