Explanation of Light Noun

1. Brightness

Brightness refers to the luminous intensity emitted in a given direction by dividing the area of a micro unit around a point on a surface by the area of the unit projected in the same direction. The unit is: cd/c ㎡. The concept of brightness is generally not encountered in lighting systems.

2. Illuminance

Illuminance refers to the luminous flux density on a surface, which is the luminous flux injected into a unit area, and the unit is LX. The definition and measurement of illuminance are more complex, such as average cylindrical illuminance, equivalent spherical illuminance, scalar illuminance, etc., and their measurement conditions and calculation methods are different. Often encountered in construction and decoration engineering, lighting system occasionally involves the concept of illumination.

3. Luminous flux

Luminous flux refers to the light source in the unit time away from the surrounding space radiation, can cause visual response energy, that is, the energy of visible light. It describes the effective radiation value of the light source, the unit is 1m (lumens). The luminous flux of lamps of the same power may be completely different because of their different luminous effects. For example, ordinary lighting bulbs are only 10 1 m/W, while metal halide lamps can reach 80 1 m/W.

4. Color temperature

Color temperature refers to the color emitted by the light source and the color of the black body at a certain temperature radiation is the same, the temperature of the black body is called the color temperature of the light source, generally in kelvin k. For example, 3200k and 5600k. The color temperature is high, the color of the light is cold: the color temperature is low, the color of the light is warm: when the color temperature is moderate, the light is close to white. Under normal natural sunshine, the color temperature of light is generally higher than that of artificial lamps. Under normal circumstances, the color temperature of sunlight is about 5600k, while the color temperature of the studio and the performance lamps is about 3200k (thermal light source). However, the recent rise of cold light sources in television studios is a change in traditional light sources. The cold light source has high color temperature, low energy consumption and low heat generation. When taking indoor and outdoor photography, the color temperature conversion is simple and the picture is natural. Of course, the cold light source has higher performance requirements for the dimming station.

5. Channels

In modern light control, a new concept of channel has emerged. It refers to a collection of control loops on a luminaire. Specifically, the function of a lamp needs to be controlled separately (for example, focusing, stroboscopic, discoloration, etc.), and the collective name of the output circuit of the dimming station is the channel. For example, the functions of a computer lamp include aperture, color, strobe, dimming, horizontal movement and vertical movement of the lens, so that they occupy 6 channels. It can be seen that the concept of the channel or the traditional light control loop evolved, but the modern lighting is the collection of multiple channels in a unified control of the device. Of course, the more advanced, more complex, and more action lamps, the more channels may be occupied, and the higher the requirements for the light console. For example: a 108 light path, with digital output dimming station, it wants to control a computer lamp with 12 channels, so it can only control up to 9 such lamps, how to control is the problem of signal and address allocation.

6. Analog control signal

It is a signal that directly uses low voltage signals to control lamps or silicon boxes. Now generally used 0~10V voltage signal as analog control signal. Usually used in stage dimming, speed control and some simple effect lighting control. Its advantages are: signal generation, acceptance and processing is relatively simple. There is no need to add any processing equipment, the use is intuitive, and the maintenance is relatively easy. Especially in the dimming control, the analog control signal can easily achieve stepless dimming. In some important places, due to the consideration of reliability, some computer lamps and lanterns need to be controlled by special personnel, so analog signal control is generally used. Its disadvantages are: signal transmission is more troublesome, and each loop must have a separate signal path. This is why the signal input interface is thick and large on analog control equipment with more signal channels (it There are dozens of hundreds of inserts); at the same time, the anti-interference ability of analog signals is also relatively poor.

7. Digital control signal

It is the use of digitally encoded bit signals to control information (including parameters and addresses), including a multi-data control signal, commonly used in modern computer lamps and digital control equipment. Its biggest advantage is: the use of a signal line can be dozens of hundreds of optical path information quickly and accurately transmitted to the corresponding equipment, and the transmission distance is very long, high anti-interference, the same type of digital control signal can also be easily combined with each other. Its disadvantage is that the corresponding coding and receiving equipment is more complicated, and under the existing technical conditions (coding and processing technology), the information it can accommodate is still limited. There are two types of digital control signals that are commonly used:

1)lRS232 digital signal (also known as PMX)

It is a serial digital encoded signal, introduced by the British company Pulsar. Generally, a 3-core or 5-core XLR plug-in interface is used, of which 1 is a shielded ground and 2 and 3 are signal paths. This signal is mainly used on pulsar console and lamps and silicon boxes receiving this signal.

2)DMX512 digital signal

It is also a serial digital encoded signal. Due to its wider and wider use, it has gradually become a standard for light control signals. With the existing transmission ratio and signal processing capabilities, it can transmit the optical path output signal to 512 optical paths. When using DMX512 digital signals, in order to ensure accurate signal transmission, it is necessary to use a termination resistor at the end of the signal line.

3) Address coding

Address coding is a concept that is generated simultaneously with digital control signals. It refers to the determination of lamps or other light-driven devices at a specific location controlled by digital signals, that is, to give them an approximate address number in the signal control system of the lighting device. The address code can express the actual position of the lamp in the system, that is, the address code in the true sense: it can also express the starting position of the channel contained in the lamp in the system. To be precise, the address at this time should be the limbs of the channel. Generally, address encoding is completed by an address encoder, and a plurality of two-gear DIP switches on the address encoder are generally used for address setting. What needs to be clearly pointed out for address coding is that the 1, 2, 3, 4...... and other consecutive numbers on the general address encoder refer to the number of the DIP switch of the encoder, not the real address coding. The difference between address coding and DIP switch values is easier to understand. Because the digital signal is binary coding, so the address coding is also integrated into this idea, it uses the corresponding DIP switch on and off to achieve the purpose of digital coding. Actually. The address code corresponding to the Nth DIP switch is regular, that is, 2n-1, that is, the exponential form of 2. In addition, the address code is in the form of the sum of the address codes corresponding to the DIP switches. For example, the address code corresponding to the above address encoder should be 1 4 8=13, which means that this address code is set to the 13th lamp of the system or the 13th channel in the system. If the device includes multiple channels, then its DIP switch setting is the address code of its first channel, with subsequent channels arranged in sequence. For example, the device has 12 channels, and its DIP switch sets the address to 13, so the channel address occupied by the device in the system is from 13 to 24.