LED Annunciator Window Fascia Units

Binay LED (Light Emitting Diode) annunciator windows provide HIGH RELIABILITY of indication in mission-critical control and fault annunciation

Annunciator window units play a crucial role in control and fault annunciation. The reliability of indication is very important for control applications, as failure can have catastrophic consequences. These are normally back-lit with conventional filament bulbs from the rear.

These annunciators are normally back-lit with con-ventional filament bulbs from the rear. However, filament bulbs suffer from the disadvantages of a short life (1000 hours only) and high power con-sumption, apart from being susceptible to vibration. These problems are further aggravated when cheap filament bulbs of inferior quality are used, as their failure rate is extremely high.

BINAY LED Matrix Annunciator Windows utilise solid-state LEDs and offer the following advantages over filament bulbs:
  • A long life of 100,000 hours (nearly 11 years on a con-tinuous burning basis - as such, the question of re-placement does not arise)
  • Extremely low current consumption (20mA - 40mA) - this may reduce complexity in solid-state logic cir-cuits, since driver transistors and thyristors can be avoided. Furthermore, when using filament bulbs, the high ratio of cold/hot resistance requires the use of highly over-rated electronic components, which can withstand high current surge at switch-on. With the use of LEDs, this problem is eliminated.
  • Totally shock-proof and vibration-resistant (as LEDs are solid-state devices)
  • Ability to withstand a wide range (+/-25%) of voltage variation without any appreciable change in life or light output.

However, the greatest advantage that the LED An-nunciator Window offers over the filament bulb type is the reliability of indication. The failure of the fila-ment bulb at a critical juncture due to its limited life or as a result of vibration can cause an expensive mishap, and it is for this reason that many design-ers emission of the LEDs used, etc. Furthermore, the material with which the legend plate is made has to be highly translucent.

BINAY LED Matrix Annunciator Windows use multi-ple high-intensity LEDs to achieve a satisfactory and uniform light output. These LEDs are positioned on a replaceable printed circuit board in a matrix form, and as a result, the legend plate is illuminated in an extremely uniform manner. This plate itself has just the right amount of transmission so as to optimise the compromise between uniform diffusion over its outer surface and too much absorption of light.

For better legibility in high ambient light conditions, high contrast is required between the light trans-mitted through the window and the light incident on its surface. As such, a dark background for the legend plate (which reflects a minimal amount of in-cident light) gives highly improved visibility.

For such conditions (where the ambient light is high), we can also provide 'Negative' legend plates. These have a dark background with transparent letters (as opposed to a white background with the legend inscribed in dark letters). This gives a supe-rior effect, as a result of the high contrast obtained by the transparent legend being back-lit on a dark background.

Legend engraving can be furnished either on a clear plate or a black background. On request, legends on photo-film transparencies can also be supplied.

designers and users prefer to install these LED windows even though the cost is higher.

LEDs, however, suffer from some limitations, which require suitable modifications to be made in the de-sign of the end product. Filament bulbs radiate light in all directions, and one light source is usually ade-quate; however, when using LEDs (which have di-rectional light emission) a multiple-LED source is required, arranged so as to give wide dispersal of the emitted light over the entire annunciator legend plate. To enable this result, various factors have to be considered in the design of the window - its depth, the positioning of the LEDs, angle of light.

BINAY LED Matrix Annunciator Windows are avail-able in any voltage rating from 5V to 220V. Legend colours can be red, green or yellow-white, with the possibility of different partitions in different colours.

A flashing arrangement can also be provided. All types in high voltage ratings (110V/220V) can be supplied with internal circuitry for fast flashing (120 flashes per minute), slow flashing (60 per minute) and steady conditions. Various terminations such as solderable lugs, screw terminals, clip-on ('El-mech' type) conductor terminals, or multi-pin con-nectors can be provided.

Annunciation Arrays: Annunciator windows can be supplied in arrays on special order. The num-bers of rows and column should be intimated. An external bezel fixes the array on the main panel.

BINAY LED Annunciator Windows come with a free-replacement guarantee against manufacturing defects and operational failure for a period of one year from the date of purchase. The normal life of an LED, however, is 100,000 hours (11 years) cal-culated on a continuous burning basis, as com-pared to 1,000 hours for a properly manufactured filament lamp (a ratio of 100:1). As such, the ques-tion of replacement of an LED indicator does not normally arise.

BINAY LED Matrix Annunciator Windows are available in the following standard types:

BINAY Model External Bezel
Size (mm)
Panel cutout
(mm)

9696M 96x96 92x92
7656AAA 76x56 64x54.5
7353A 73x53 59x39.5
7052AA 70x52 56x44
7035BC 70x35 56x27
6550AB 65x50 51x36
6443B 64x43 50.5x30.5
5530C 55x30 41x22.5

Apart from the Model number (as above), mention voltage rating, type (AC or DC), colour of illumination and type of leg-end background (clear or black) when enquiring.