Advanced LED lighting - Max-i Fieldbus

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Advanced LED lighting
Integrated LED controller
The Max-i controller includes a state-of-the-art LED controller with a lot of outstanding features:

  • Suitable for even the most demanding stage light and architectural lighting applications (DMX512 replacement).
  • Pulse code modulation with 1.25 µs pulses (not PWM) for very small decoupling capacitors, no flicker or stroboscopic effects, no discomfort and very long LED life (less thermal stress). Pulse width modulation (PWM) below 800 - 3000 Hz may create headache, nausea, eye exertion and eye fatigue even though the flicker is not directly visible.
  • No violation of the Signify (previous Philips Lighting and Color Kinetics) PWM patent for color changing (RGB) lamps with communication or the similar Infineon sigma-delta patent.
  • 4 x 8-bit, 6-color RGBWaAaC system with automatic generation of artificial amber (aA) and artificial cyan (aC) on the basis of RGB.
  • Build-in gamma correction of 2.44 (very close to the eye curve) to increase the contrast ratio and keep the color hue constant during dimming.
  • Contrast ratio of over 11,000:1.
  • 3rd order smoothing filter on each color with 7 time constants (bypass, 2.5 ms, 5 ms, 10 ms, 20 ms, 40 ms, 80 ms and 160 ms), which may be selected on a per-telegram basis. This can reduce the necessary telegrams per second considerably and makes it for example very easy to make short, but smooth light flashes with different rise and fall time by means of only two telegrams.
  • 6-bit dot correction on each color removes the necessity for expensive bin selected LED's.
  • Integrated one-button or two-button light dimmer with 54 levels, night light, programmable start level and synchronized multi-way landing switching.
  • Possibility to control two lamps from one controller so that Max-i can replace ordinary dual wall switches without limitations, but with a lot of added features.
  • Daylight control (dimming) in up to 255 groups with all-off (and all-on) function and slow smoothing filter to convert the 54 levels to 216 steps and in this way make each step invisible.
  • Possibility for emergency light with programmable color in case of a communication failure.
  • Integrated traffic light controller with dimming, programmable minimum level and green safety output.

The very advanced controller has previously unseen control possibilities. Without changing the settings, a lamp can simultaneously be controlled and dimmed by means of wall buttons and automatic daylight control, be set to a specified color for example by means of a mobile phone or tablet and be controlled together with other lamps in a common group telegram with individual reception delay to set a scene or even control the lamps in real time from for example a TV set or a computer with the same speed and performance as professional stage light.

With the 6-color RGBWaAaC system, which can generate excellent pastel colors, and the possibility to address many light sources in the same telegram, the lamp controller is perfect for illuminated ceiling panels with diffused light where it can create an illusion of being outside with drifting clouds and varying color temperature depending on the time of the day. This may for example be used to create a pleasant feeling in stores, treatment rooms in hospitals and in rooms without daylight such as rooms in the basement. The ceiling may simultaneously hide alarm sensors etc., which can just be connected to the same bus.

If 6 colors are not enough, any number of Max-i controllers can very easily collaborate by means of common telegrams. Just two controllers where the reception in one is delayed 4 bytes can create an absolute state-of-the-art 8-12-color system at a previously unseen low cost. With for example a royal-blue, blue, artificial cyan, green, lime, artificial amber, orange, red and deep red system, any color and color temperature can be created with excellent accuracy for example for lighting in art museums etc. Because of the inherent possibility for battery backup, the lamps for such applications can simultaneously be used for emergency lighting, which can even show the way to the nearest exit by means of running light for example controlled by means of a common group telegram. In case of smoke where white light gets scattered, the light may even change to red or reddish, which makes it easier to find the way out. If the lamps are equipped with sensors, they can simultaneously be used for alarm systems for example for burglary and fire so that only a single lamp unit may do it all.

Automotive Matrix Headlamps
The same properties, which makes Max-i perfect for stage light, also makes it very suitable for matrix headlamps, which makes it possible to increase the safety considerably by travelling with permanent high beam and maybe also with permanent fog lamps without risk of dazzling oncoming traffic or any preceding vehicles. The light is controlled by means of a camera or a row of light sensors, which detects the light from oncoming vehicles and reflected light from road signs and dims the light in these directions so that neither the oncoming driver nor the driver himself are dazzled.

Some matrix systems splits the high beam into 5 reflectors, each one having a chip containing 5 LED's so that the light can be individually controlled in 25 directions. With Max-i, this could be replaced with 6 reflectors with each 4 LED's and a Max-i chip, and it is then possible to utilize the many outstanding properties:

  • Choice between linear or gamma correction according to the characteristic of the camera or the light sensors.
  • The publisher/subscriber model makes it easy for each headlamp to utilize the same messages, and all LED's can be controlled in a single telegram.
  • Because of the smoothing filter, it is not necessary with more than 10 - 15 telegrams per second so very little data processing is needed. Without these filters, the LED's need to be updated at least 75 times per second to avoid flicker, which can even cause epileptic seizures.
  • No flicker caused by interference between pulse width modulation (PWM) and vibrations.
  • The dot correction may be used to ensure the same light level in all directions.
  • The possibility for a programmable light level in case of a communication failure increases the error tolerance and safety.
  • Unlike other systems, where each LED strips off the used bytes and then transmits the rest of the telegram to the next LED's, Max-i is a parallel system, so the communication line does not need to be broken and a failure on one chip does not affect the operation of others.

Traffic Lights
For many reasons, Max-i is also perfect for driving traffic lights:

  • It makes it possible to replace all the expensive and thick multi-core cables and belonging connection boxes with a single balanced 4-wire loop.
  • It saves all the expensive controller-I/O for point-to-point connections to lamps, loop detectors and pedestrian pushbuttons. This saves a lot of money too and makes it possible to drive everything from a microprocessor with the size of a credit card.
  • It is very easy to connect a laptop PC or tablet to the bus for programming and debugging so there is no need for an operation panel.
  • The excellent dimming possibilities with group control and programmable minimum level makes it easy to optimize the light intensity in each direction according to the ambient light and solar radiation in that direction. This can save a lot of power and prevent dazzling of the drivers at night.
  • The inherent possibility for battery operation can easily prevent the traffic from breaking down in case of a power failure. This is especially important in critical situations like terror where a loss of traffic lights very fast makes it impossible to evacuate people and get rescue vehicles and police through.
  • In case of a power failure, the lamps can be dimmed to save power and in this way make the batteries last much longer.
  • The 4-bit boolean values fits perfectly with the usual number of lamps in a lantern (in one direction).
  • It is possible with automatic and synchronized flash with two flash frequencies and programmable phase for each lamp.
  • The publisher-subscriber mode makes it possible to update all lamps i one direction simultaneously.
  • It is possible to control any number of lanterns by means of a common telegram.
  • It is designed for maximum safety according to IEC 61508 SIL 3 (death of 1-3 persons) and even has a green safety output with own decoding circuit to prevent green light in case of a failure.

This page is created with WebSite X5 and updated May 10th 2021

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