Yonghan is waiting downstairs in the company. A young man from Tengcheng arrived by taxi. He carried a large bag with some multimeters, circuit boards, and wires.
Yonghan said: "Hello, welcome to Shengshi City."
Guan Lirong said: "Hello, brother."
Yonghan said: "Landian Company has told you what we want you to do this time."
Guan Lirong said: "As I said, add some sensors."
Yonghan said: "Let's go to the dungeon now. I'll take you there."
Yonghan drove him to the entrance of the dungeon, swiped his card to open a heavy door, and saw the elevator.
Yonghan said: "This elevator is also newly installed."
After a while, we reached the 4th underground floor.
Yonghan introduced: "This is an underground city with many transmission lines and transformers."
Guan Lirong said: "What specifically do you need me to do?"
Yonghan said: "Add some sensors to detect voltage, current, temperature, and control switches."
Guan Lirong said: "Okay, I understand, and then I need to know the specific parameters and installation location."
Yonghan took him to various places and pointed out the installation location.
Guan Lirong said: "I've heard of this place."
Yonghan said: "Have you heard of it too?"
Guan Lirong said: "I have heard of you too."
Yonghan said: "Really? Is it about good things or bad things?"
Guan Lirong said: "Shengcheng whirlwind. Regardless of his own safety, he rushed into the eye of the storm, started the fan, generated a whirlwind, offset the original whirlwind, and stopped the heavy rain."
Yonghan said: "It is better to do more good deeds and accumulate virtue and do good deeds."
The good deeds he thinks of are Taoist goodness. Taoism promotes a kind of "unintentional" goodness, "non-contentious" goodness, which is a kind of natural "goodness". Let go of your obsessions, let nature take its course, and seek spiritual liberation and inner freedom. Taoist kindness means forgiving oneself and others, and having no disputes with others and the world. This kind of goodness can be said to be the highest good, and it is a great virtue in line with the way of heaven.
Yin virtue is the superior virtue; Yang virtue is the lower virtue. A virtuous person will be consistent in his words and deeds before others and will not deceive others. He can be "cautious in being alone". A person of low virtue is utilitarian in doing good deeds, needs rewards, and never forgets them. This is a small act of kindness. Some are hypocritical and do good deeds, just for superficial reasons.
Zheng Yonghan thought that he really wanted to do something good.
Guan Lizong said: "In the circle of skilled workers, you are also a role model."
Yonghan said: "Thank you. After thinking about it, it is what I, an electrician, should do."
They walked forward for a while, and circuits and sensors had been installed in some places.
Yonghan said: "Sensors have been installed in some places. However, they have been affected by moisture or damaged by mice. They need to be repaired."
Guan Lirong said: "I brought a multimeter and wires, let me take a look first."
The sensor is connected to the measurement circuit and there are many different ways of communicating. Some are voltage signals, some are current signals, some are digital signals, some are frequency signals, and some are bus signals. The voltage signal will not be transmitted very far. If it is too far, a voltage drop will occur due to the resistance of the wire.
Many are bus signals, and multiple sensors are transmitted to the same controller through the bus. Many of the analog signals from sensors are relatively weak and require an amplification circuit to amplify the signals.
A non-inverting amplifier or an inverting amplifier can be used to amplify the signal. The amplification factor of a non-inverting amplifier is equal to 1 plus the feedback resistor divided by the input resistance. The amplification factor of the inverting amplifier is equal to the negative number of the feedback resistance divided by the input resistance ratio. Generally, the input impedance is relatively small and needs to be improved. The output impedance of the sensor is generally relatively large. If the input impedance of the measurement circuit is small, it will be difficult for the signal to be transmitted to the subsequent stage.
Lirong measured that a sensor had no output signal. It turned out that there was a problem with the amplification circuit, so the circuit was replaced. Then the measurement output is normal.
Sensor signals may introduce high-frequency noise signals and low-frequency background signals. This is when you need to use a filter. Use a bandpass filter to filter out high- and low-frequency signals, leaving the mid-band signals through.
The controller end generally receives digital signals. The voltage and current signals from the sensor need to be converted into digital signals, or the current signals into voltage signals, the voltage signals into frequency signals, and then sent to the controller.
He measured it step by step, and it seemed that there was a problem with the intermediate voltage-to-frequency circuit.
There is also a frequency multiplication direction identification circuit behind the frequency signal processing circuit. For example, a 10-fold frequency circuit can increase the resolution of the original sensor by another 10 times. Place two sensors 90 degrees apart on the motor's speed measuring device. According to the detection signal, one signal is in the upper high level range or the low level range of the other signal, and it can be judged whether the motor is rotating forward or reversely.
Here the subdivision circuit is used to detect electric energy, and the electric energy meter outputs a frequency signal. It seems that the sliding rheostat was accidentally moved, and then continued to adjust the sliding rheostat to adjust the output signal to 10 times the frequency.
Yonghan was waiting nearby, sometimes handing over a multimeter and wires.
Guan Lirong said: "In addition, some measurement circuits have not been completed, and the measurement circuit and controller need to be redesigned."
Yonghan said: "Okay. You can go back and make and repair some devices again."
Guan Lirong said: "This place is a little damp."
Yonghan said: "For some things that physically absorb moisture, the air needs to be dried. Otherwise, the circuit is easy to be damaged. You are quite skilled at doing this. Okay, I basically checked everything today. Let's go up."
On the way back, Lirong considered rebuilding the control panel. In fact, this design contains quite a lot of content. Choose a processor that matches your needs, consider factors such as processor reliability, performance, power consumption, and cost, and determine processor selection based on processor architecture and interface adaptability. Design the system's hardware architecture based on requirements and selected processors. Including device selection, circuit board design, signal analysis, power management, and more. According to the requirements, design the software architecture of the system, determine the functions and relationships between each module in the system, and design data communication methods, etc. Write a low-level driver that matches the hardware so that each peripheral can work and transmit data normally. Write applications to implement various functions required by the product. Through simulation, unit testing and integration testing, the system is debugged and tested to ensure that the product can meet the needs and is stable. After testing and verification, it will enter the mass production stage.
Yonghan said: "How long does it take to make a circuit board?"
Guan Lirong said: "These sensors will not affect the use of the substation, right? It will take at least 5 days."
Yonghan said: "Then I'll wait for your news."
Guan Lirong said: "Okay."
