1.The origin of PCM relay
It was first developed by A Rivers proposed in 1937 that pulse code modulation laid the foundation for digital communication. This method was first applied to urban telephone networks in the 1960s with the aim of expanding their capacity and increasing the transmission capacity of most core lines of existing audio cables by 24-48 times.
With all these improvements, by the mid to late 1970s, some countries were able to apply pulse code modulation to medium to large capacity transmission systems, such as coaxial cable communication, microwave relay communication, satellite communication, and fiber optic communication.
2.The Development of PCM Relays
In the early 1980s, pulse code modulation was applied to local telephone relay transmission, high-capacity relay transmission, and digital program-controlled switches, and was used for user telephones. In fiber optic communication systems, binary optical pulse "0" and "1" codes are transmitted through fiber optic cables, which are generated by modulating the switch state of the light source with binary digital signals. Digital signals can be generated by sampling, quantization, and encoding continuously changing analog signals, known as PCM, which stands for Pulse Code Modulation. This type of electrical digital signal is called a digital baseband signal generated through PCM electrical terminals.
Currently, all digital transmission systems in operation use pulse code modulation systems. Initially, it was not used to transmit computer data, but to establish relay lines between switches instead of just transmitting a telephone signal. There are two standards: expression form E1 and T1.
3.PCM relay structure and characteristics
Structure: It consists of a control circuit, a drive circuit, and contact components. Generally speaking.
characteristic：
1. Programmable: Implement certain control logic through programming; It is flexible. It can be set according to the requirements of different applications and can meet the requirements of various complex control situations.
2. High precision control: It can achieve high-precision time control and logical judgment, ensuring the accuracy and reliability of control. In situations where high-precision control is required, such as sequential control and timing control in industrial automation production lines, PCM relays can be utilized.
3. Miniaturization design: Compared with traditional relays, PCM relays are usually much smaller in size and are suitable for use in places with limited space. For example, in some small electronic devices or intelligent control systems, PCM relays are easily installed on circuit boards to achieve a compact design.
4. Multi functional integration: In addition to the basic functions of relays, PCM relays can also integrate counters, timers, data storage, and other functions to perform multiple control functions within a single device, reducing system complexity and cost.
4.The working principle of PCM relay
Once an external input signal is received, the signal is processed by a given pre programmed control logic. Then control the contact action of the relay to achieve on/off control of the circuit.
5.The function of PCM relay
It can be used for power switch in the circuit. In case of failure of a main power supply, the system automatically switches over to the backup power supply in order to provide uninterrupted power to critical equipment. It can also be used for controlling load on/off for achieving on-demand power supply and improving energy efficiency. Meanwhile, overcurrent, overvoltage, and short-circuit protection can be installed in order to prevent abnormal situations that may damage equipment and a circuit. Besides, it can also be used as a switch for transmitting the signals to realize the isolation of the signals and prevent interference and fault propagation between different circuits or systems. For automation control, remote control of equipment may be realized by its cooperation with sensors and controllers to arrive at automatic control. The roles played by the PCM relays are indispensable in circuit control, protection, transmission of signals, and automation.
6.What is PCM power relay?
PCM power relays also perform a lot of functions in automobiles. Many functions are performed with the help of computer control. Along with this, it will also be used for the management of the engine. Still, there will be an engine control module which will manage the engine and its related functions.
It will also monitor the operating conditions via ECM and control the power distribution of fuel and injection systems, Engine timing, emissions, ignition, exhaust circulation, etc inside the vehicle.
On the other hand, ECM requires power to transmit it into each system.
How does it get this power?
The power distribution center is located under the hood of the car. It is designed in a way that it controls all the car relays and fuses. A switch that has become known as the PCM power relay-or sometimes ECM power relay-has always carried out the switching function of sending the power to the ECM. After your ignition key is turned off, however, the switch inside the PCM power relay likewise will fail to get the power from the battery. For that reason, it will not allow your car to run the way it usually would.
This is because, when the PCM relay stays open, it cannot distribute the power to the ECM. In other words, that is the reason you cannot open and start the car. If it stays closed, the ECM will be getting too much power. Consequently, the battery will get drained out.
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