I. All RC4 devices have the ability to use the wired RDM control protocol
A. This includes RC4 2.4GHz devices, 900MHz devices, LumenDim and W-DIM devices
B. RDM is particularly useful with W-DIM devices
C. The process is demonstrated using a Goddard Design miniDMXter4
II. Using a Goddard Design minDMXter for RDM
A. In this application, the miniDMXTer and the DMXter are operated virtually the same.
A. An RC4 DMX-to-miniplug adaptor is needed to work with devices equipped with a standard XLR5 or XLR3 connector
B. Plug the DMX five pin cable into the DMX512 out on the miniDMXter
C. Plug the miniplug into the RC4 W-DIMm3 DMX port
D. Turn on the DMXter
1. When the DMXter screen command asks to transmit DMX 512, press the black Up button on the DMXter
2. The next screen will read RDM controller; press the middle white button
3. The screen will then display Discover RDM devices; press the middle white button
4. When the screen says Discover new devices, press the middle white button
5. On device discovery, the screen will read Discovery Complete, Found One Device
a. Press the white center button
6. The miniDMXter will ask if the current device should be selected
a. Press white center button to select
7. The Choose Sub Device screen will appear on the miniDMXter
a. The root is where the sensors are located
b. There are also three dimmers in the W-DIMm3
(1.) They are sub-devices, they are the actual dimmers, the power handling in the W-DIMm3
c. To choose a dimmer, press the black up button on the miniDMXter
d. In this example, sub-device 3 is chosen by pressing the center white button
8. The screen will read RDM Controller Device information
a. Press the white center button
9. The screen will read RDM Controller Set DMX information
a. Press the white center button
10. The DMX address is set
11. Press the gray Back button, then the black Down buttons until the screen reads E1. 37-1 RDM features E1. 37-1 RDM featuresThe original ANSI E1.20 Remote Device Management (RDM) specification outlines a bare-bones set of device parameters. Additional parameters that are useful for dimmer control were added with ANSI E1.37. RC4 devices support many of those additional features.
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a. These are an extension of the basic RDM PIDsRDM PIDRemote Device Management (RDM) is a protocol enhancement to USITT DMX512 that allows bi-directional communication between a lighting or system controller and attached RDM compliant devices over a standard DMX line. Various RDM features and commands are called Parameter Identifiers (PIDs). For example, to set a DMX channel with RDM, the PID for “set DMX […]
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b. These features include dimmer curvesDimmer curvesAn instrument’s dimming curve is simply how bright the light is in relation to the level of the associated DMX channel. A good dimmer should be perceived by your eye to be smooth and linear: if you set a light level of 50%, the lamp should appear to be half as bright as it does at 100%. […]
Read more », smoothing timeSmoothing timeRC4 Digital Persistence softens LED dimming to provide the appearance of incandescent lamps. This is done by introducing a smoothing time. To emulate larger traditional lamps, smoothing time is longer; to match the appearance of smaller lamps, a shorter time is used. For very fast blinks and strobes, no smoothing is introduced at all.
Read more » and PWM frequencyPWM frequencyTo see a visual representation and in-depth explanation of PWM, watch our latest video This chart is also a helpful resource. PWM stands for Pulse-Width Modulation. It is a method for using a switching device (one that can only be on or off) to create what appears to be analog changes in level. This is done by […]
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c. Press the white button in the center
(1.) To see a variety of dimming options, scroll through the screens using the buttons on the miniDMXter
(2.) There are 12 dimming options, including ISL, linear, non-dim, inverted ISLInverted ISLThe inverted ISL curve works backwards, with the highest level being off, and the lowest level being full. If two dimmers are assigned to the same DMX channel, one set to ISL and the other set to inverted ISL, they will smoothly cross-fade LEDs as the channel level changes. (Note that in this case it […]
Read more », inverted linearInverted linearThe inverted linear curve works backwards, with the highest level being off, and the lowest level being full. If two dimmers are assigned to the same DMX channel, one set to linear and the other set to inverted linear, they will cross-fade as the channel level changes. (Note that in this case it is not […]
Read more », inverted non-dim, servo motor pulseServo motor pulseHobby servo motors, like those made by Futaba, JR, and many others, are controlled using a short digital pulse. The length of this pulse controls position. RC4 offers a dimmer curve that provides this pulse, making it easy to control servo motors with any RC4 Series 3 dimmer output.
Read more », AC synthAC synthAC synthesis is the creation of alternating current (AC) using direct current (DC) electronics and special software. In RC4 Series 3 dimmers, this is done using two 2 DC dimmers in tandem. AC power is needed to make a telephone ring, or make EL wire light up. It is the kind of power that comes from a […]
Read more », DC motor bi-directionalDC motor bi-directionalThe direction that a DC motor spins is determined by the polarity of the power applied to it. To change the speed and direction of a DC motor, the power level and the polarity must both be controlled. A bidirectional motor controller provides this functionality.
Read more » and 16-bit raw16-bit rawOne DMX channel provides 8-bit digital resolution, which is 256 steps. Ganging two channels together provides 16-bit resolution, which is 65,536 steps and is much smoother when dimming LEDs. You can think of this as coarse and fine channels controlling a single load, where the fine channel provides 256 levels within one value of the […]
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d. In this example, servo motor pulse is chosen
(1.) The miniDMXter screen reads good response (if this is not the case, simply retry)
e. Using the back button, the screen for response time is located
(1.) There are eight output response times available
(2.) These options range from no smoothing to very slow smoothing
f. Press the Back and Down buttons to reach the modulation frequency page
(1.) There are seven options available
(2.) The options range from 77hz to 40kHz
(3.) Lower frequencies handle more power more efficiently, higher frequencies avoid visible artifacts when capturing video
E. Using RDM is a good way to access the internal dimmer parameters in any RC4 Series 3 wireless product
III. More info on the DMXter and the miniDMXter can be found HERE