Four key control points for the quality of studio lighting system construction

Figure 1 is a typical studio lighting system.

Figure 2 is a diagram of a typical suspension control system.

Figure 3 is a schematic diagram of dimming and through loop control.

Key to construction quality of mechanical suspension system

During the construction process, due to the convenience of construction and material saving considerations, the following quality problems that have a great impact on safety often occur:

(1) The two ends of the wire rope are fixed. GY5070—2013 “Construction and Acceptance Specifications for TV Studio Lighting Systems” requires that the total bearing capacity of wire ropes should not be less than 10 times the total lifting weight. In general, the weak link of the bearing capacity is fixed at both ends of the wire rope. Commonly used fixing methods are shown in Figures 4 and 5. Practice has proved that the fixing method of the drum end is very safe, but the fixing method of the steel wire rope and the horizontal boom is in some extreme cases, the wire rope in the buckle may cause slippage, which may cause a major quality accident. An improved fixing method is shown in Fig. 6. In Fig. 5, the wire rope lifting force is mainly supported by the frictional force of the buckle and the wire rope. In the way of Fig. 6, the lifting force is supported by the friction force and the tension of the wire rope itself, and the lifting force is greatly improved. According to the third-party tensile test data, the locking method in Fig. 5 is slipped under the condition of 1000Kg tension under the same torque locking condition, and the slipping in the fixing mode of Fig. 6 exceeds 4000Kg.

(2) Quality of wire rope. In some cases, during the production, storage and transportation process, there may be lap joints, twists, broken strands, rust, bends, pouting, looseness, etc. Among these phenomena, the situation of lap joints and strand breaks is relatively hidden, and it needs to be carefully checked to identify them.

(3) The limit and protection device of the mechanical system shall be installed and debugged. The suspension device must be installed with upper and lower limit positions and overload protection devices. Electric booms and hangers must be provided with loose rope protection and anti-shock protection devices. The setting of the lower limit should be considered convenient for the user's operation, and the upper limit setting should be set strictly in accordance with the specifications. It should be noted that when the upper and lower limits are set, the limit parameters of all the suspension devices in the studio should be set to be consistent. This debugging process requires multiple types of work and patient commissioning. Figure 7 shows a typical upper and lower limit device. In this device, according to the height of the studio, the displacement of a wire of the positioning nut corresponds to a few meters of the boom. To ensure the consistency of the height of the upper and lower limits of all the booms, it is necessary to finely adjust the initial positions of the two positioning nuts. Determine the limit parameters. During the commissioning process of the loose rope protection device, the elastic piece matched with the elastic coefficient of the steel wire rope should be selected. The wire rope breaking rope disturbance should cause the elastic piece to be denatured to achieve the purpose of cutting off the motor power supply.

The anti-shock protection device generally adopts the method of hanging the safety hammer, and should pay attention to the safety of the protection device itself. The safety hammer should be provided with a safety chain.

Key to construction quality of weak current system

In the lighting system, the weak current system includes a wide range, including at least the following parts: dimming DMX signal control system, cloth optical LAN control system, lighting digital and mechanical three-action (or more action) light control system. The dimming control system is developing in the direction of networking. At present, some TV stations have begun to deploy DMX dimming systems and LAN dimming systems at the same time. In the above system, special attention should be paid to the following matters during construction: (1) The integrated wiring of the weak current system should be shielded and isolated from the dimming and straight-through circuits. There are a large number of odd harmonics in the dimming circuit, which generate a lot of electromagnetic interference. (2) Determination of the grounding method of the DMX signal. The DMX 512 control line uses a 5-pin XLR connection. (3) Cable end processing and wiring line sequence. The network cable generally uses the cable clamp to make the crystal end. After the connection is completed, the network tester is used for testing. The connection method is different and the test method is different.

Dimming and straight-through loop construction quality key

Compared with ordinary power supply circuits, dimming and straight-through circuits have their special characteristics: first, there are many circuits, and second, electromagnetic interference is large. During the construction process, pay attention to the following items:

(1) All supply circuits and three power cables should be laid in the same channel to avoid interference and eddy currents.

(2) The bridge of the straight-through and dimming circuit from the dimmer chamber to the studio should be carefully calculated before purchasing. In the system integration process, the size of the eighty-nine is too small, resulting in cable congestion, which is not conducive to post-maintenance and heat dissipation.

(3) The connection of the cable ends. Cable ends generally have two connections: screwing and crimping, as shown in Figures 8 and 9, respectively. In the power box, terminal box and adapter box of the lighting system, it is generally connected by screwing. In the silicon box terminal block, most of them are connected by crimping.

(4) Testing of cable insulation resistance. The studio lighting system has a large amount of cable laying, and the bridge design has a relatively small interface size, so cable straining often occurs during cable laying.

System function test

System function testing is the key to verifying the success of a project. A complete lighting system consists of multiple subsystems, each with its own subsystem. The engineering test should first start the test from the function of each subsystem. After the functional test of each subsystem is completed, the system test will be carried out. After the system test is completed, the system joint test will be carried out. Table 1 is the system division and test content.