Research on the Status of Stage Lighting Control System

- Nov 30, 2017 -

Research on the Status of Stage Lighting Control System

 

Summary:

In the process of the development of the entertainment equipment industry, stage lighting control technology occupies a very important position. A simple study of the stage lighting control technology will help us to have a more profound understanding of lighting control technology. This article gives an overview of the status quo of stage lighting control technology briefly from the three aspects of control system, console and dimmer.

 

Keywords: stage lighting; controller; dimmer

 

1 Introduction

 

As an important artistic component in theatrical performances, light cooperates with live performances on stage to achieve the artistic effects of simulating nature, creating moods, expressing emotions and cutting the stage, time and space with its unique means. And these artistic effects are usually reflected in the light and shade (brightness), light color, light projection direction and the beam effect and other means of expression and its dynamic combination. All of these light effects must be controlled by the lighting control device to perform good brightness control, color conversion, beam motion control and so on. The composition of the control system. The composition of the stage lighting control system can be divided into the weak part of the control and the strong part of the power supply.

 

2 control section

 

Control of the stage lighting can be divided into three basic systems, namely wither control system, scanner control system, color changer control system. On the connection and life, has gone through simulation, digital (DMX), the Internet three times. In the analog and digital era, the three major control systems are basically independent of each other, self-contained system, entered the era of the Internet. Three systems synthesized a large system. Strengthen the control function, convenient management.

 

2.1 lighting control analog connection

In the early days of thyristor wedges, the dimming control was dimmed by changing the resistance of one of the resistors in the trigger circuit. Widely used in the resistance-capacitance phase-shift trigger circuit is a typical example. This small form of resistor control can be centralized control, only a single light south staff operations. After improved into a voltage control, so that multiple centralized control possible. Light console sends control voltage to each dimmer through multi-core cable to realize wither control. This is enough to simulate the stage withered connection.

 

2.2 light control digital connection

 

The birth of computer lighting consoles and digital dimming cabinets made digital lighting of stage lights possible. It is possible to get rid of the desire to get a lot of control lines.

 

2.3 light control network connection

Although network technology is essentially digital technology, the development of computer networks. Bring new vitality to the stage lighting. The development of lighting control technology has had a huge impact.

 

2.3.1 stage lighting control network

With the development of theatrical arts and science and technology, the stage lighting is getting bigger and bigger in scale, and its function requirements are getting higher and higher. In particular, large-scale square and theatrical performances of the stadium and the special requirements of the theme park for lighting control, lighting control network Has become inevitable. Computer network industry is a much larger industry than the entertainment industry. There is a strong technology development force, and network technology in all walks of life around the world have been widely used. There are a large number of cheap equipment available for selection. With strong and mature computer network technology support. Light control network has a solid foundation.

 

2.3.2 lighting network control system

 

Lighting control network system composed of different system sizes, functional requirements and different products will be different, but the same basic principles. Of course, the main components of the stage lighting control network are light console, digital dimming cabinet, computer lights, color changers and other lighting equipment, but the application of network technology and some network equipment such as network distributors (usually switches and hubs) Cables connect them to form a local area network (LAN). Due to the current DMX protocol, such as dimmers, computer lights and other equipment, so in the light control network needs to be between the Ethernet and DMX signal conversion. In order to achieve remote monitoring also need a video signal conversion. These are the "network nodes" specially developed by the stage lighting equipment manufacturers to implement [1].

 

3 strong power system

High-power part of the light source of energy. Although not as complicated as the control section, it is also a basic part of the lighting that is very important. The power section can be divided into the power supply section before the dimmer and the light circuit section after the dimmer or the straight-through switch.

 

3.1 lighting power supply system

 

Lighting power supply system is part of the theater power supply system. Theater power supply system transformer room, low voltage distribution room, transmission cables and other components.

 

3.2 light line system

 

A lot of light on the stage is dimming by a dimming device, which is the main part of the stage lighting - incandescent light source to provide electricity. But some do not need to dimming, we call it through, this part of the line is mainly for the use of gas discharge light source of computer lights, high power projection slide and other equipment power supply, but also for lighting control in some mechanical accessories such as The color changer motor (after the power signal divider), effects, automatic lights and other power supply. Therefore, the lights in the stage should be distributed in a sufficient number of dimming and direct line.

 

4 Scanner console principle

The control system of the computer light is usually composed of several computer lights and matching computer light console combination. They are connected in series by a multi-core control cable (XLR). Connection method (Figure 4-1). Unified operation by the computer console, staff only programming in front of the console to control the action of all the computer lights. Computer lights equipped with one or two single-chip microprocessor (also known as SCM). Single-chip processor is the CPU and a small amount of RAM, ROM, and I / O port made of a silicon integrated. Monolithic microprocessor signals. Through the drive circuit to make all micro stepping motors in the machine move, so as to drive each color wheel, gobo, lens and mirror movement, resulting in a variety of colors and shapes of the beam and its movement in space [2].

 

Computer light console to make a computer light to do some action. First of all to find this computer lights. Console to identify the same DMX signal in a computer lamp, you must find the address code to solve. Therefore, each scanner must be set before using the address code.

 

Due to the different manufacturers of computer lights. 512 channels have two kinds of representation. One is 000-51l, one is 001-512. Therefore, the setting of scanner address code starts from 000 and starts from 000. Computer lights address code is through the computer lights on the binary code switch. With the switch ON, the leftmost digit represents "1", the second digit to the left represents "2", the third digit to the left represents "4", the fourth digit to the left represents "8" The fifth left represents "16" and so on. If you use a 16-channel scanner. The first is 001 computer lights. The first scanner address code is 00 1 the leftmost switch is turned on, said "l"; the second scanner address code is 001 + 016 = 017, the first switch is connected, and the fifth switch Dial; the third computer lamp address code is the sixth left, the first switch is turned on, said 32 +1 = 33 and so on. This set the address code for each scanner, you can control through the console.

 

5 Dimmer

5.1 digital dimmer

From large transformer to trigger thyristor components for dimming, great improvements have been made in the functions, benefits, thermal control and even the volume of the device. Early silicon components rely on pure hardware for triggering, when the input signal only self-control pushrod and 0 ~ 10V analog. Later, the successful development of the digital signal DMX512, in the traditional analog silicon with a digital decoder before the digital dimmer has become the time, but this is not all-digital dimming, the real digital dimming must be digital signal input and After the three-phase synchronization signal is input, all the functions (dimming curve, minimum / maximum output, adjustment and silicon trigger output) are all completed by the processor [3].

 

5.2 silicon trigger mode

In the early dimmer products, the triggering method for the thyristors was pulse firing. The method was to pulse the TRIAC to turn on when the phase angle needs to be turned on (brightness adjustment) 220V AC / 50Hz sine wave returns to 0 automatically shut down, and in the next cycle, repeat the action. At that time, the lamps and lanterns used were purely resistive load or high power, so the basic requirements of dimming can be met.

 

If you want to ensure that the inductive / electromagnetic resistive load will not cause oscillation and let the load flicker, you must use the hard trigger (HardFiring) to handle the silicon conduction. When the incoming power is oscillating through a non-inductive resistive load, it is impossible for the interfering power source to provide normal power to the passive components for legitimate and successful triggering. The disadvantage of hard trigger mode for the high cost of manufacturing and product size is relatively large, most of the product design in the form of a single silicon or large silicon cabinet appeared in the market.

 

5.3 Sine wave dimmer

 

Prior to the 1960s, the dimming equipment on the stage, from the salt water tank to the large power variable resistor, dimmed the lamp load by changing the sine wave of the AC power supply. The disadvantage of this form is the large amount of thermal energy lost and the huge volume, but the advantage is that there is no disturbing noise. The invention of one-way thyristors (SCRs) and triacs (TRAICs) has made dimming diminished in volume, lowering the operating temperature and controlling the dimmer with a low-voltage signal, which is what we are familiar with Dimmer. But this way of triggering the phase-cut waveform brings us the problem of intermittent current in the power system. In a standard three-phase supply system, these harmonics can increase the neutral current to 1.4 times normal. Harmonic will produce audible noise, will make the power transmission system of metal conductors and even transformer transformers produce high fever [4]

 

EU countries advocate the development of legal provisions "dimming system must be low-level harmonic leakage" principle. On the other hand, the disadvantages of using phase cut waveform dimmers on the market are becoming increasingly apparent. More and more luminaires are not purely resistive loads in the past. Later dimmers using IGBT as the power amplifier components reverse phase cut waveform, technically canceled bulky filter coil, but the original phase-cut waveform problem still exists, but only to reduce weight.

 

In addition, some working voltage can not be lower than some of the value of the electrical appliances, such as ballasts, neon tubes, motors, etc., can be pre-set their minimum operating voltage. Then, like adjusting the incandescent light bulb, adjust the pressure. In other words, all types of loads can be dimmed / regulated by SST sine wave dimmers

 

6 Conclusion

Modern stage lighting control system design is the direction of network digital intelligent dimming. With the rapid popularization of the Internet and continuous improvement of the quality of professional lighting personnel, the automated lighting control system with advanced technology, stable performance, flexible control, convenient operation, complete functions and economic durability will add luster to the Chinese stage.


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