There are various types of Siemens PLCs, such as Siemens PLC S7-200 series and Siemens PLC S7-300 series, which are widely used in various industrial automation fields. During use, users need to process analog signals to implement various logic. The following article introduces the Siemens PLC analog processing method, in order to better use Siemens PLC for users.   Siemens PLC Analog Processing Method     1. Standard signal In the era of electric sensors, central control becomes possible, which requires long-distance transmission of detection signals. However, the direct transmission of complex physical signals will greatly reduce the applicability of the instrument. Moreover, most sensors belong to the weak signal type, and long-distance transmission is prone to attenuation and interference issues. Therefore, secondary transmitters and standard electrical transmission signals emerged. The function of a secondary transmitter is to amplify the sensor signal into an electrical signal that meets industrial transmission standards, such as 0-5V, 0-10V, or 4-20mA (among which 4-20mA is more commonly used). By shifting the zero point and adjusting the gain of the amplifier circuit, the transmitter can accurately correspond the standard signal to the detected range of physical quantities, such as 0-100 ℃ or -10-100 ℃. This is a mathematical transformation of physical quantities using hardware circuits. The instruments in the central control room drive these electrical signals to mechanical voltmeter and ammeter to display the measured physical quantities. For different range ranges, simply replace the dial behind the pointer. Replacing the dial will not affect the fundamental nature of the instrument, which brings unlimited benefits to the standardization, universality, and large-scale production of the instrument. If you are looking for a reliable and efficient variable PLC, come to Rockss Automation to take a look and perhaps find a satisfactory product. We have different brands of PLC,such as Siemens PLC, Allen-Bradly PLC, Schneider PLC,etc.         2. Digital instrument  In the digital era, pointer display meters have become more intuitive and accurate digital display methods. In digital instruments, this display method actually uses a purely mathematical method to invert the standard signal, becoming a common way of expressing physical quantities. This transformation relies on software for mathematical operations. These operations may be linear or nonlinear equations, and today's computers are easy to handle these operations.     3. Mathematical problems in signal transformation The transformation of signals requires the following process: physical quantity - sensor signal - standard electrical signal - A/D conversion - numerical display. For simplicity, we are discussing linear signal transformations here. Simultaneously skip the signal transformation process of the sensor. Assuming the physical quantity is A, the range is A0-Am, and the real-time physical quantity is X; The standard electrical signal is B0-Bm, and the real-time electrical signal is Y; The A/D conversion value is C0-Cm, and the real-time value is Z. Thus, B0 corresponds to A0, Bm corresponds to Am, Y corresponds to X, and Y=f (X). Due to its linear relationship, the equation is obtained as Y=(Bm B0) * (X - A0)/(Am A0)+B0. Due to its linear relationship, the mathematical equation Z=f (X) after A/D conversion can be expressed as Z=(Cm C0) * (X-A0)/(Am A0)+C0. So it is easy to conclude that the mathematical equation for inverse transformation is X=(Am A0) * (Z-C0)/(Cm C0)+A0. The X calculated in the equation can be directly expressed as the detected physical quantity on the display.     4. Calculation method of inverse transformation in PLC Taking Siemens PLC S7-200 and 4-20mA as examples, after A/D conversion, we obtained values of 6400-32000, C0=6400, and Cm=32000. So, X=(Am A0) * (Z-6400)/(32000-6400)+A0. For example, a certain temperature sensor and transmitter detect -10-60 ℃, expressed as X=70 * (Z-6400)/25600-10 using the above equation. After calculating the mathematical operation instructions of the PLC, the Siemens HMI can read from the result register and directly display it as engineering quantity. Using the same principle, we can input engineering quantities on the HMI and then convert them into standardized values used by the control system through software. In Siemens PLC S7-200, the calculation results of (Z-6400)/25600 are very important values. This is a real number from 0 to 1.0 (100%) that can be directly sent to the detection value input of the PID instruction (not the instruction wizard). The PID instruction outputs real numbers from 0 to 1.0, which can be converted into 6400 to 32000 through the inverse calculation of the previous formula, and sent to the D/A port for 4-20mA output.      Our team of experienced professionals is dedicated to delivering personalized services that exceed our customers' expectations. We offer a diverse range of services,including after-sales and maintenance, among others. Our team is composed of experienced engineers and technicians who are highly skilled in the maintenance and troubleshooting of PLCs.

What is the PLC? PLC (Programmable Logic Controller) is a widely used programmable controller in the industrial field. The application of PLC technology can achieve digital, networked, and automated control of various production equipment, improving production efficiency and work quality. With the continuous improvement of industrial automation level, the application range of PLC is also expanding.   Basic structure A PLC is essentially a computer dedicated to industrial control, with a hardware structure similar to that of a microcomputer, consisting of a CPU, I/O board, display panel, memory, and power supply.  1. Power supply The power supply of PLCs plays a very important role in the entire system. Without a good and reliable power supply system, it cannot work properly. Therefore, manufacturers of PLCs also attach great importance to the design and manufacturing of power supplies. Generally, the fluctuation of AC voltage is within the range of+10% (+15%), and the PLC can be directly connected to the AC power grid without taking other measures  2. Central Processing Unit (CPU) The central processing unit (CPU) is the control center of a PLC. It receives and stores user programs and data input from the programmer according to the functions assigned by the PLC system program; Check the status of power supply, memory, I/O and alert timer, and diagnose syntax error in user program. When the PLC is put into operation, it first receives the status and data of various input devices on site through scanning, and stores them in the I/O image area respectively. Then, it reads user programs one by one from the user program memory, interprets commands, and executes logical or arithmetic operations according to the instructions. The results are sent to the I/O image area or data register. After all user programs have been executed, the output states or data in the output registers of the I/O image area are finally transmitted to the corresponding output devices, and the cycle continues until it stops running. In order to further improve the reliability of PLCs, redundant systems with dual CPUs or voting systems with three CPUs are also used for large programmable logic controllers. In this way, even if a CPU fails, the entire system can still operate normally.  3. Memory The memory that stores system software is called system program memory. The storage for storing application software is called user program storage. 4. Input output interface circuit 1) The on-site input interface circuit consists of an optical coupling circuit and an input interface circuit of a microcomputer, serving as the input channel for the interface between the PLC and the on-site control. 2) The on-site output interface circuit is integrated with output data registers, gate circuits, and interrupt request circuits, and functions as a PLC to output corresponding control signals to the on-site execution components through the on-site output interface circuit.  5. Functional modules Functional modules such as counting and positioning. 6. Communication module       Our company Rockss Automation Technology Co. Ltd. has been a leading provider of automation solutions for several years, and with our extensive inventory, we can fulfill all your automation needs. Our PLCs are of the highest quality and trusted by businesses of all sizes worldwide.      We have a wide range of PLCs available, and each of them is designed to meet specific needs. Our PLCs are developed to maximize efficiency and cut costs while providing reliable and accurate automation solutions. They are also manufactured using the latest technology and the highest quality materials, ensuring excellent performance and longevity.     Functional characteristics PLCs have the following distinct characteristics.   1. Easy to use and simple programming Adopting concise programming languages such as ladder diagrams, logic diagrams, or statement tables without the need for computer knowledge, the system development cycle is short and on-site debugging is easy. In addition, the program can be modified online to change the control scheme without dismantling the hardware.   2. Strong functionality and high cost performance ratio A small PLC has hundreds or thousands of programming components available for users to use, which have strong functions and can achieve very complex control functions. Compared with relay systems with the same function, it has a high cost performance ratio. PLC can achieve decentralized control and centralized management through communication networking.   3. Complete hardware support, convenient for users to use, and strong adaptability PLC products have been standardized, serialized, and modularized, equipped with a variety of hardware devices for users to choose from. Users can flexibly and conveniently configure the system to form systems of different functions and scales. The installation and wiring of PLC is also very convenient, usually connected to external wiring through terminal blocks. PLC has strong load capacity and can directly drive general solenoid valves and small AC contactors. After the hardware configuration is determined, the user program can be modified to quickly and conveniently adapt to changes in process conditions.   4. High reliability and strong anti-interference ability Traditional relay control systems use a large number of intermediate relays and time relays, which are prone to malfunctions due to poor contact of the contacts. PLC replaces a large number of intermediate relays and time relays with software, leaving only a small number of hardware components related to input and output. The wiring can be reduced to 1/10-1/100 of the relay control system, greatly reducing faults caused by poor contact of contacts. PLC adopts a series of hardware and software anti-interference measures, with strong anti-interference ability, with an average time between failures of tens of thousands of hours or more. It can be directly used in industrial production sites with strong interference. PLC has been recognized by users as one of the most reliable industrial control equipment.   5. Low workload in system design, installation, and debugging PLC replaces a large number of intermediate relays, time relays, counters and other devices in the relay control system with software functions, greatly reducing the workload of control cabinet design, installation, and wiring. The ladder diagram program of PLC is generally designed using sequential control design method. This programming method is very regular and easy to master. For complex control systems, designing a ladder diagram takes much less time than designing a circuit diagram for a relay system with the same function. The user program of PLC can be simulated and debugged in the laboratory, with input signals simulated using small switches. The status of the output signal can be observed through the LED on the PLC. After completing the installation and wiring of the system, problems discovered during the on-site debugging process can generally be solved by modifying the program, and the debugging time of the system is much shorter than that of the relay system.   6. Small maintenance workload and convenient maintenance The fault rate of PLC is very low, and it has complete self diagnosis and display functions. When a malfunction occurs in the PLC or external input devices and actuators, the cause of the malfunction can be quickly identified based on the information provided by the LED or programmer on the PLC. Replacing the module can quickly eliminate the problem.       At Rockss Automation Technology Co. Ltd., we are committed to providing our clients with nothing but the best. That's why we have a range of brands to choose from, including Siemens, Allen-Bradley,SIEMENS , and more. With our vast inventory, we can supply PLCs for industries such as automotive, pharmaceuticals, food and beverage, and more.    Below is an introduction to several brands of PLC sold by our company: 1.Allen-Bradley PLC 2.B&R PLC 3.SIEMENS PLC   4.ABB PLC 5.Schneider PLC    Our team of experienced professionals is dedicated to delivering personalized services that exceed our customers' expectations. We offer a diverse range of services,including after-sales and maintenance,among others. Our team is composed of experienced engineers and technicians who are highly skilled in the maintenance and troubleshooting of PLCs.    When you purchase PLCs from us, you can rest assured you are getting the best value for your money. With our competitive pricing, exceptional quality, and unparalleled service, we want to ensure our customers have nothing but the best experience when they partner with us.    In conclusion, Rockss Automation Technology Co. Ltd. is the perfect partner for all your automation needs. Whether you need PLCs for industrial, manufacturing, or commercial purposes, we have it all. Our commitment to providing quality products and services at competitive prices, coupled with our experienced team of professionals, is what sets us apart. Contact us today and let us help you streamline your automation needs.