There are a lot of people who don't know much about the power sequencer. As the name suggests, the power sequencer is a sequencer for controlling the on/off of the powered device. The power is turned on one by one from the previous device to the subsequent device, and the power is turned off. It is one of the indispensable equipments for all kinds of sound engineering, television broadcasting systems, computer network systems and other electrical engineering to shut down all kinds of electrical equipment from the later stage to the former stage.
What is a power sequencer?
The power sequencer, simply by means of the internal control circuit of the device, sequentially turns the power output on or off according to the established program, and the power supply voltage and the load device are managed. The voltage can be accurately monitored and the volume is smaller. From 1U to 3U standard racks, there are mainly 8, 10, 12, 16 channels. Widely used in automatic control, television broadcasting systems, audio broadcasting, power facilities and other systems.
In the audio equipment, the correct shutdown procedure is to turn off the power amplifier first, and then turn off the pre-stage equipment such as the exciter, the crossover, the mixer, etc.; First turn off the power amplifier to prevent the noise from being generated by the front-end equipment and damage the speakers and amplifiers. By using the power sequencer and accessing different switch sockets, it is possible to start the power supply from the pre-stage device to the post-stage device one by one. When the power supply is turned off, the opposite is true, and the various types of electric equipment are effectively and uniformly managed to avoid The man-made error operation reduces the impact of the power equipment switch on the power supply grid and ensures the stability of the power system.
Application of power sequencer in audio system
Is it used first or not? If in some fixed occasions, such as large venues or performances, the entire system has professional operations, the sound engineer or operator can use the audio equipment very skillfully, and it is completely unnecessary to use the timing switch. After all, the simpler the system, the fault occurs. The lower the rate. Even with the use of the sequencer, its function is relatively powerful, such as multi-level cascading, CPU control, computerized management, etc., stability and power capacity is also relatively large. So in a certain sense, the timing switch is more suitable for beginners. In most occasions, such as the conference room of the unit, the background music system, the karaoke business place, the middle and low-end Di Bar, the personal home entertainment system, the fixed installation of small and medium-sized venues, and the slow shake bar, etc., there are very few Professional sound engineers are operating, and some are like stage cars, mobile performance sound systems, school public address systems, and also part-time management equipment. The normative operation is not strong, you need to add appropriate timing power management for users. Better mastery. Facts have proved that in some current engineering configurations, the timing device power supply has almost become a standard equipment. How to properly select, correctly apply, timely maintain and discover hidden dangers in advance is a new subject faced by audio technology practitioners.
How to choose a power sequencer?
First, stability
Stability is overwhelming. No matter what you buy, everyone should think about it. If the sequencer is unstable, then there is no way for the system to be good. Of course, in addition to the stability of the power sequencer itself, it is also necessary to resist external interference. What can interfere with the power sequencer? Mainly caused by surges and pulse spikes caused by lightning, electric motors, fluorescent lamps, etc.; another aspect is the internal power supply charging or switching power supply interference when the system is started.
At this time, everyone will think, how to test the stability of the power sequencer?
Step 1, turn on the power sequencer, set the timer interval to 1 second, then start the power sequencer, and then switch the fluorescent lamp or electric drill in the room during the startup process. At this moment, pay special attention to the timing device. There can be no restart or there is a channel open, this method has to be tested multiple times. If it is possible to inject the interference pulse into the power supply (220V) of the sequencer by the pulse generator, the interference intensity is increased in the test to test the anti-interference intensity of the measured sequencer, generally reaching 1KV ( 1000V) or more. This first step of the test is complete.
Step 2, we passed the first test, and then each load of the power sequencer is connected to the load. Here, it is better to use a high-power amplifier. In the case of not having so much load, the load can be connected to continuous After the road (such as CH12, 11, 10, 9). Then power up the sequencer and start the timing start function (note that if the timing interval is adjustable, the interval should be adjusted to 1 second), and the start process cannot see that the sequencer cannot be restarted or the channel is not open.
Second, capacity:
The overall current demand of the system is the standard for selecting the capacity of the sequencer. Currently, there are 20A, 30A, 40A, 50A currents available for selection; the capacity of a single channel is generally 10A or 13A; now some manufacturers blow their own 30A relays. The output current is up to 30A, while the output block uses American or universal sockets. The rated current of this seat is 10A, and some thickened shrapnel is 13A. It can be seen that the output current is not up to 30A. Everyone can test it with a load of 30A (of course, burn out the output seat, don't look for me; huh...); use a load of 10A when testing (I generally use Electric heating rod, must buy well, to test the current.), receive the nominal total capacity current, boil water for 4 hours (water should be enough, some people must be on the scene when testing, pay attention to safety). The surface temperature of the power lead should not exceed 60 degrees, and it is not hot to the touch; the timing device can not emit a paste. (It is recommended not to try it easily, so as to avoid danger, you can buy regular manufacturers products.)
Third, the function:
According to the requirements of the project, such as level start function, RS232, RS485, TCP/IP control function, status monitoring; timing interval, normally open configuration function; power supply purification, anti-surge, voltage, current monitoring and protection functions.
Fourth, scalable:
The number of output channels of the power sequencer is divided into 4 channels, 8 channels, 10 channels, 12 channels, etc. When the number of devices exceeds the number of one sequencer channels, it is extended (cascading), and attention should be paid to the expansion when selecting. After that, it can be opened from the first road to the last road. It can also be closed from the last road to the first road. Many of the timing devices in the market can't meet this requirement. At the same time, each station is closed at the same time.
Scalability, the channel of the general power sequencer output is roughly divided into 4, 8, 10, 12 channels, etc. When a power sequencer cannot meet all the devices, it needs to cascade other power sequencers, and it needs to be used. To the extended features.
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