RC4 OneTouch To Set DMX Channels and Dimmer Curves

These instructions apply to all RC4 Series 3 Harmonized Design devices, including:

  • RC4Magic Series 3 and RC4Magic-900 DMX2dim, DMX4dim, DMX4dim-500
  • LumenDim4, LumenDimM4
  • W-DIM4, W-DIMm3

DMX channel and curve selection is a Single-Press Button Feature as described in detail in http://rc4.info/s3-ui-nomenclature/.


A Live DMX Connection is Required

Connect a DMX data source (the output from your DMX controller) to the DMX data input on your wireless DMX transmitter.  Be sure your transmitter is powered on and operating, and be sure your RC4 device is paired with your transmitter.  When using an RC4Magic system, be sure all devices are programmed with your private and unique system IDs, and the same ID is selected for each device.


Assign DMX Channels

You probably don’t want to run all your wireless dimmers on the default DMX channels 1 through 4.
RC4 OneTouchTM makes it easy to assign any DMX channel and dimmer curve to any dimmer with a single press of a single button.

Start by clearing all your DMX channels to zero on your controller.  Be sure this includes any “special” channels, like house lights and work lights, and be sure you are not using fixture profiles that “home” some channels at levels other than zero.  For example, some moving light fixture profiles will send X and Y motion to a midpoint when the console is “cleared.”   That midpoint is not zero; for our purposes, you need actual zero.

If you are unsure if all channels are really at zero, check your DMX line with a tester, like a Goddard DMXter or a Fleenor Gizmo.  These are very handy devices to have around, for all kinds of reasons.  Put this on your wish-list!

Bring up the level of any single DMX channel;  set a fader to about 1/3 of the way up, or type in a channel level of 30%.

Go to your RC4 dimmer and press the SetA button.  You’ll see the DimA indicator come on at 30% brightness.  When you let go of the button, the dimmer should stay on.  It is now assigned to the channel you have up.

If the dimmer does not stay on when you release the SetA button, the wireless link to the transmitter is probably not established.  Streaming DMX data is required for this process.

Fade the assigned channels up and down from your DMX controller.  Your wireless dimmer will track it exactly.  It will remember your channel assignments, even if you turn it off.

As of firmware v4.050, RC4Magic dimmers assign channels consecutively to all available device dimmers when SetA is used to assign a channel and curve to DimA.  In many cases, that’s all you need. If you need non-consecutive channels or different dimmer curves for each dimmer, you can use the same OneTouch process individually with SetB, SetC, and SetD.  These buttons affect only their associated dimmers.  That is, only SetA will change the channel and curve settings for all the dimmers in the device.

If the dimmer came on brightly when you pressed the button, and did not stay on after you released the button, the data connection to the transmitter is not working.  Go back to the previous steps and get it dimming up and down with default DMX channel settings. Then proceed to setting other DMX channels.

Setting the channel to 30% tells the dimmer to use a combination of options that make LEDs look great, ideal for viewing the little indicator on the dimmer device itself.

You can set the channel to levels other than 30% to select configurations that are optimized for other kinds of loads.  Each dimmer can be set to a channel, curve, PWM frequency, and RC4 Digital Persistence level, accommodating the needs of various different kinds of load you can connected to an RC4 dimmer.


RC4 OneTouchTM Channel, Curve,
and Digital PersistenceTM Assignment

When an RC4 Series 3 device is connected to an active transmitter with DMX data streaming in, the Set buttons provide RC4 OneTouchTM dimmer configuration.  Press a dimmer Set button to assign that dimmer to the first DMX channel that is at a level higher than 20%.  The level of the DMX channel determines the dimmer curve, RC4 Digital Persistence time, and PWM frequency.

As of firmware v4.050, the SetA button assignes all dimmers in the device to consecutive DMX channels, all with the same dimmer curve, PWM frequency, and Digital Persistence time.  The other Set buttons affect only their specific dimmer.  It is still easy to have each dimmer configured completely independently, just be sure to configure DimA first.

Dimmer Curves

Using RC4 OneTouchTM, three different dimmer curves can be selected: Inverse Square Law (ISL), Linear, and Non-Dim 1.

The ISL Curve is optimized for light emitting diodes (LEDs).  You must use the ISL curve to make LEDs dim smoothly; do not use the linear curve for LEDs.

The Linear Curve is perfect for incandescent (including halogen) lighting – traditional filament bulbs.

The Non-Dim Curve is ideal for relays, solenoids, AC inverters, and anything else that needs cleanly switched DC power. 


As of firmware v4.050 a parameter in RC4MagicPC software allows you to replace the OneTouch-selected Non-Dim curve with any other available curve.  This makes it easy, for example, to assign the AC Wave curve for ringing a telephone, without needing to pull out a computer and software.  The factory default setting is Non-Dim.

RC4 Digital PersistenceTM  

The ISL dimming curve is only part of how to make LEDs look great.  RC4 Digital PersistenceTM makes LEDs look as pleasing as incandescent lighting, with no visible stepping, by emulating the natural filament persistence of vintage lamps.  Using RC4 OneTouchTM, the ISL curve can be selected with or without RC4 Digital Persistence by using the ISL-Slow or ISL-Fast dimmer curve. 

PWM Frequency

All RC4 Series 3 dimmers provide a range of PWM frequencies.  Low frequencies must be used with high-power loads, particularly incandescent lamps.  Higher frequencies are best for LEDs, to eliminate visible flicker.  Using RC4 OneTouchTM, the default frequency for the Linear Curve is 77Hz; the default for the ISL Curves is 615 Hz.

These defaults are user selectable using RC4MagicPC software.  There are 8 Digital Persistence speeds.  As of firmware v4.050, PWM frequencies are 615Hz, 1230Hz, 5kHz, 10kHz, 20kHz, and 40kHz.

Easy RC4 OneTouchTM Channel Level Chart

Dimmer Curve,
RC4 Digital PersistenceTM(DP),
PWM Frequency
Level % (0-100) Level Dec (0-255) Level Hex (0-FF)
No Digital PersistenceTM,
No Modulation
(80% or higher)
(205 or higher)
(0xCD or higher)
No Digital PersistenceTM,
77Hz PWM
(60% – 79%)
ISL Fast,
No Digital Persistence,
Default is 615Hz PWM
(40% – 59%)
ISL Slow 1,
Default DP is Fast Medium 2,
Default is 615Hz PWM 2
(20% – 39%)
Channel Ignored
(No change to current settings)
Less than 20% Less than 52 Less than 0x34
  1. If you are unsure about which curve to use, try the ISL Slow curve. If your load is drawing a lot of power and the dimmer is getting hot, use the Linear curve.
  2. Default PWM frequency and RC4 Digital PersistenceTM time are user adjustable. See the complete RC4 Series 3 User Manual for details.
  3. As of firmware v4.050 a parameter in RC4MagicPC software allows you to replace the OneTouch-selected Non-Dim curve with any other available curve.  The factory default setting is Non-Dim.

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