1. Core viewpoints
1.1 There are significant differences in programming, each with its own merits
There are significant differences between Mitsubishi PLC programming software and Siemens PLC programming software in many aspects. From the perspective of programming concept, Mitsubishi programming is intuitive and easy to understand, relatively easy to learn, and has many instructions. Its programming software has a top-down single vertical structure from the early FXGPWIN to the recent GX8.0. Siemens programming instructions are more abstract and difficult to learn, but there are fewer instructions. Its programming software such as MicroWIN has both vertical and horizontal structures, and subroutines support local variables. The same function only needs to be programmed once, which greatly reduces development difficulty. and time.
In terms of functions, Mitsubishi PLC performs well in discrete control and motion control, and has dedicated positioning instructions. Controlling servo and step is easy to implement. For example, high-speed counter instructions are more convenient than Siemens. But in terms of floating-point operations and analog input and output, Siemens has obvious advantages. S7-200 has always supported powerful floating-point operations, and the programming software directly supports decimal point input and output. However, Mitsubishi did not have this feature until the FX3U series launched in recent years. At the same time, the analog input and output program of S7-200 is very simple and convenient. AD and DA values can be directly accessed without programming. Mitsubishi's FX2N and its previous series require cumbersome FROM TO instructions.
1.2 The selection must be based on actual conditions and accurate matching
Enterprises should fully consider their actual needs when choosing PLC programming software. If the company's equipment is mainly for motion control, such as manipulators, or if there are servo or stepper for positioning control, then Mitsubishi PLC may be a more suitable choice. Because Mitsubishi has rich instructions in this area, it is easier to achieve complex motion control. And if the enterprise's equipment has a lot of analog quantities to be processed, such as central air conditioning, sewage treatment, temperature control, etc., or there are many instrument data on site that need to be collected through communication, then Siemens PLC is more suitable. Siemens has obvious strengths in process control and communication control. Analog modules are cheap, simple in program, and easy to communicate. In short, only by rationally selecting PLC programming software based on actual needs can efficient control be achieved and production efficiency and equipment reliability improved.
2. Comparison of programming concepts
2.1 Mitsubishi programming is intuitive and easy to understand
2.1.1 Suitable for small control systems
Mitsubishi has more programming instructions, which gives you more tools when working with small or medium-sized control systems Available to choose from. For example, in some small automated production lines, Mitsubishi PLC can quickly implement various logic controls through rich instructions. Its programming logic structure is relatively simple, and its top-down single vertical structure makes the program flow clearer and easier to understand and maintain. For small control systems, this structure can meet basic control needs and does not require too many complex programming skills. In the control of some small equipment, such as small packaging machines, small injection molding machines, etc., Mitsubishi PLC can quickly respond to control requirements and achieve precise action control.
2.1.2 Low learning threshold
Mitsubishi programming is intuitive and easy to understand, which is mainly reflected in the interface design of its programming software and the expression of instructions. . From the early FXGPWIN to the recent GX8.0, the interface of the programming software has always maintained a relatively simple and clear style, allowing users to get started quickly. The expression of instructions is also relatively intuitive. For example, when performing logic control, Mitsubishi's ladder diagram instructions are relatively similar to the actual electrical schematic diagram, making it easier for people with a certain electrical foundation to learn. In addition, Mitsubishi PLC provides rich annotation functions during the programming process. Users can make detailed annotations on key parts of the program to facilitate subsequent maintenance and modification.
2.2 Siemens programming is abstract and rigorous
2.2.1 Suitable for large and complex systems
Siemens programming focuses on abstraction, which means that it focuses more on the overall architecture and logical relationships of complex systems description. Siemens programming software such as MicroWIN adopts both vertical and horizontal structures, which can better adapt to the needs of large and complex control systems. In large-scale industrial production processes, such as automobile manufacturing, steel smelting and other fields, multiple equipment and systems need to be controlled collaboratively. Siemens PLC can achieve efficient control of the entire production process through its rigorous program structure and powerful communication functions. . At the same time, the subroutines of Siemens PLC support local variables, which enables better management and maintenance of variables when writing complex programs and improves the readability and maintainability of the program.
2.2.2 Command refining is difficult to learn
Siemens’ instructions are more refined. Although this reduces the number of instructions to a certain extent, it also increases the number of instructions. Difficulty of learning. For example, Siemens' programming languages mainly include LAD, FBD, STL, SCL, etc. Each language has its own specific application scenarios and scope of use. For beginners, it takes more time to learn and master these. Language grammatical rules and programming ideas. In addition, the operating interface and functions of Siemens programming software are relatively complex, requiring users to have a certain computer programming foundation and engineering practice experience. During the parameter setting and debugging process, you also need to have an in-depth understanding of the system's hardware structure and working principles, otherwise errors will easily occur.
3. Software interface and operating experience
3.1 Siemens interface modernization
3.1.1 Feature-rich
Siemens' programming software interfaces are generally more modern and feature-rich. For example, it supports online debugging. Engineers can monitor the status of various variables in real time while the program is running and quickly locate problems, which greatly improves the efficiency of development and debugging. At the same time, the simulation operation function is also very powerful. It can simulate the operation of the system without connecting the actual hardware, discover potential problems in advance, and reduce the time and cost of actual debugging. In addition, the software also supports a variety of advanced functions, such as data recording and analysis, fault diagnosis, etc., providing engineers with a full range of development and maintenance tools.
3.1.2 Humanized operation
The operating experience of Siemens programming software is more user-friendly. Its interface layout is reasonable, the design of menus and toolbars is concise and clear, and it is easy to operate. For commonly used functions, the software provides shortcuts and shortcut keys to facilitate engineers to quickly call them. During the programming process, the software will automatically prompt grammatical errors and logical errors to help engineers correct errors in time. At the same time, the software also supports custom settings. Engineers can adjust the interface layout and function settings according to their own habits and needs to improve work efficiency.
3.2 Mitsubishi interface is traditional and stable
3.2.1 Traditional interface style
Mitsubishi's programming software is relatively traditional, and the interface style may be slightly outdated. Compared to Siemens' modern interface, Mitsubishi's software interface may not be visually appealing enough. However, this traditional interface style also has its advantages. For some engineers who are accustomed to traditional programming software, it is easier to get started and adapt.
3.2.2 Strong stability
Mitsubishi programming software has excellent performance in terms of stability and can meet the needs of long-term stable operation. In an industrial production environment, system stability is crucial. After years of development and optimization, Mitsubishi Software has achieved a high degree of stability and reliability. Even during long runs, glitches and errors are rare. This allows Mitsubishi PLC to be used in some fields that require higher system stability, such as electric power, chemical industry and other industries.industry and has been widely used.
Fourth, instruction system and functional characteristics
4.1 Siemens instructions are rich and powerful
4.1.1 Floating-point operation is strong
Siemens PLC has a rich instruction system, among which the floating-point operation function is particularly powerful. Siemens PLC can play a huge role in situations where high-precision calculations are required, such as precision instrument control and high-end manufacturing. For example, in the automotive manufacturing industry, a large number of floating-point operations are required to accurately control the performance parameters of the engine. Siemens PLC can handle these complex calculation tasks quickly and accurately to ensure that the engine performance is optimal. According to relevant data, the floating-point calculation accuracy of Siemens PLC can reach multiple decimal places, which can meet the needs of various high-precision calculations.
4.1.2 Support for complex logic algorithms
Siemens PLC supports a variety of complex control logic and algorithms, which makes it perform well in large and complex control systems. For example, in the steel smelting process, multiple parameters such as temperature, pressure, flow rate, etc. need to be monitored and controlled in real time, and various process requirements and safety factors need to be considered. Siemens PLC can program and implement these complex control logics through its powerful instruction system. It can support advanced programming structures such as loops, conditional statements, and functions, allowing engineers to design and implement control systems more flexibly.
4.2 Mitsubishi instructions have characteristics
4.2.1 Advantages of high-speed counter instructions
Mitsubishi PLC has unique features in specific functions such as high-speed counter instructions. For example, in some occasions where high-speed moving objects need to be counted, such as packaging machinery, printing machinery and other industries, Mitsubishi PLC's high-speed counter instructions can quickly and accurately count the number of times an object moves. According to statistics, the counting frequency of Mitsubishi PLC's high-speed counter instructions can reach a very high value, which can meet most high-speed counting needs. In addition, Mitsubishi PLC's high-speed counter instructions also have a variety of working modes and triggering methods, which can be flexibly set according to different application scenarios.
4.2.2 Gradually strengthen floating-point operations
In recent years, Mitsubishi has also gradually strengthened the support for floating-point operations and other functions. With the continuous development of industrial automation, the requirements for PLC's calculation accuracy are getting higher and higher. Mitsubishi PLC is aware of this and continues to strengthen its floating-point operation function. Now, the floating-point calculation accuracy of Mitsubishi PLC has been greatly improved, which can meet more high-precision calculation needs. For example, in some occasions with very strict requirements on temperature control, such as the pharmaceutical industry and food processing industry, the floating-point calculation function of Mitsubishi PLC can achieve precise control of temperature and ensure product quality and safety.
V. Scalability and compatibility
5.1 Siemens performs well
5.1.1 Easy integration
Siemens PLC performs extremely well in scalability and compatibility, and can be easily integrated with other devices and systems. Its design concept focuses on openness and versatility, allowing different types of equipment to be easily connected to the Siemens PLC system. For example, in the field of intelligent manufacturing, Siemens PLC can be seamlessly integrated with robots, sensors, actuators and other equipment to achieve fully automated production processes. Through standardized interfaces and protocols, engineers can quickly build complex control systems to improve production efficiency and quality.
5.1.2 Rich communication interfaces
Siemens PLC has rich and diverse communication interfaces and supports multiple communication protocols, which makes data transmission and remote monitoring more convenient. For example, Siemens PLC supports mainstream communication protocols such as Profibus, Profinet, Ethernet/IP, and can communicate efficiently with equipment from different manufacturers. According to statistics, Siemens PLC can connect up to hundreds of different types of equipment to meet the needs of various complex industrial scenarios. In addition, Siemens also provides powerful network management functions, engineers can easily monitor and manage the entire network to ensure the stable operation of the system.
5.2 Mitsubishi is slightly inferior
5.2.1 Good performance
Mitsubishi PLC also has good performance in scalability and compatibility. It can achieve functional expansion through various expansion modules to meet the needs of different application scenarios. For example, Mitsubishi PLC can process more types of signals by adding analog input and output modules, high-speed counting modules, etc. At the same time, Mitsubishi PLC also supports some common communication protocols, such as Modbus, RS232/485, etc., and can communicate with other devices to a certain extent.
5.2.2 Relatively weak
However, compared with Siemens, Mitsubishi PLC may be slightly inferior in scalability and compatibility. When integrating with other devices and systems, more customized development and debugging work may be required. For example, when connecting some new intelligent devices, Mitsubishi PLC may require additional interface conversion modules or special programming settings. In terms of communication protocol support, Mitsubishi PLC has relatively few types and may not meet some complex network architecture requirements. In addition, Mitsubishi PLC's functions in network management and remote monitoring are relatively weak, requiring engineers to invest more time and energy in maintenance and management.
VI. Input and output module differences
6.1 Advantages of Mitsubishi input modules
6.1.1 Support transistor types
Mitsubishi PLC input modules support transistor types and have significant high-speed response advantages. The response time of transistor input modules is usually at the microsecond level, which can quickly capture changes in external signals and is suitable for application scenarios with high response speed requirements. For example, in high-speed automated production lines, it is necessary to detect the signals of various sensors in a timely manner in order to make control decisions quickly. Mitsubishi's transistor input modules can respond in a very short time to ensure the efficient operation of the system. In addition, transistor input modules have the advantages of low power consumption and small size, which are suitable for use in equipment with limited space.
6.1.2 Large output current
The output module of Mitsubishi PLC can provide a large current, which makes it very suitable for driving large equipment or loads. For example, the relay output type of Mitsubishi FX3U series PLC has a large output current. The circuit voltage below AC250V can drive a pure resistance load of 2A/1 point, an inductive load of less than 80VA (AC100V or AC200V), and a lamp load of less than 100W (AC100V or 200V). The output current of each output point other than Y0 and Y1 is 0.5A, but due to the temperature rise, the total current of each output is 0.8A. This large current output capability gives Mitsubishi PLC a clear advantage in driving large motors, solenoid valves and other equipment.
6.2 Features of Siemens input module
6.2.1 Relay type is usually used
Siemens PLC usually uses relay type as input module. Relay input module has high current capacity and driving capability, suitable for driving various loads, such as motors, lights, solenoid valves, etc.. It can achieve high power control and has strong voltage resistance and durability. In some application scenarios that require high reliability, the relay input module can provide stable signal transmission. For example, in some industrial control systems with high safety requirements, the relay input module can ensure normal operation even in harsh environments.
6.2.2 More suitable for small device driving
The output module of Siemens PLC is more suitable for driving small devices. Siemens output modules usually have small output current and power, which are suitable for driving some small actuators, sensors and other equipment. For example, in some small automation equipment, such as small robots, precision instruments, etc., the output module of Siemens PLC can provide precise control signals to meet the control requirements of the equipment. In addition, the output module of Siemens PLC also has good performance in response speed and accuracy, which is suitable for small equipment with high control accuracy requirements.
VII. Communication protocol differences
7.1 Mitsubishi communication protocols are diverse
7.1.1 Applicable to various scenarios
Mitsubishi PLC supports multiple communication protocols, providing flexible choices for different industrial application scenarios. Among them, the Modbus protocol is a universal serial communication protocol, which is widely used in the field of industrial automation. It supports a variety of transmission media, such as RS-232, RS-485, etc., and has the characteristics of strong versatility, simplicity and ease of use, and high reliability. In Mitsubishi PLC, the Modbus protocol adopts a master-slave structure, with the host computer initiating requests as the host and the PLC responding to the request as the slave. Through the Modbus protocol, the host computer can read and write data in the PLC to achieve remote monitoring and control of the PLC. In addition, Mitsubishi PLC also supports Profibus protocol, Profinet protocol, DeviceNet protocol, CC-Link protocol, EtherCAT protocol, MELSEC-CNET protocol, MELSEC-MEDEX protocol, MELSEC-NFC protocol, MELSEC-BACnet protocol, MELSEC-Modbus TCP/IP protocol and MELSEC-OPC UA protocol. These protocols have their own characteristics and are suitable for different application scenarios. For example, the Profibus protocol is a commonly used industrial fieldbus protocol for fast communication between PLC and distributed intelligent devices. It has the characteristics of high speed and strong real-time performance, and is suitable for complex industrial control scenarios. The CC-Link protocol is an industrial Ethernet communication protocol developed by Mitsubishi Electric Corporation. It supports multiple transmission rates and topologies and is suitable for complex industrial environments. The EtherCAT protocol is a real-time communication protocol based on Ethernet. It has extremely high data transmission rate and extremely low communication delay, and is suitable for application scenarios with extremely high real-time requirements.
7.1.2 Convenient connection
Mitsubishi PLC has a variety of communication protocols, which makes it easy to connect and exchange data with various devices. For example, through the Modbus protocol, Mitsubishi PLC can communicate with sensors, actuators, host computers and other devices that support the Modbus protocol. Through the Profibus protocol, Mitsubishi PLC can communicate quickly with distributed intelligent devices. Through the CC-Link protocol, Mitsubishi PLC can communicate with other Mitsubishi PLCs or devices that support the CC-Link protocol. In addition, Mitsubishi PLC also provides a wealth of communication interfaces and modules, which can easily realize interconnection and data exchange with various devices. In practical applications, the communication protocols of Mitsubishi PLC can be used in combination to meet complex communication needs. For example, the Modbus protocol can be used to communicate with sensors and actuators, and the Profinet protocol can be used to achieve high-speed data exchange with the host computer and monitoring system.
7.2 Siemens protocol is highly targeted
7.2.1 Mainly use specific protocols
Siemens PLC mainly uses PROFIBUS and Industrial Ethernet protocols. PROFIBUS is a fieldbus communication protocol used in the field of industrial automation. It supports multiple transmission rates and topologies and is suitable for complex industrial environments. It uses token passing to ensure that each device can send data in real time after obtaining a token. It has the characteristics of high speed, strong real-time performance and high flexibility. Siemens PLC connects to the Profibus network through the Profibus communication card, supporting DP (distributed I/O) and PA (process automation). Industrial Ethernet is a communication protocol based on Ethernet technology developed by Siemens, supporting high-speed data transmission and application scenarios with high real-time requirements. It is based on the TCP/IP protocol stack and has stable network transmission performance and easy expansion. Siemens PLC supports the Industrial Ethernet protocol through the built-in Ethernet interface or Ethernet communication card. Users can communicate with PLC through Ethernet to achieve remote monitoring and control.
7.2.2 Applicable to specific industrial scenarios
Protocols such as PROFIBUS and Industrial Ethernet of Siemens PLC are suitable for specific application scenarios that require high bandwidth and real-time data transmission. For example, in large-scale industrial production processes such as automobile manufacturing and steel smelting, multiple devices and systems need to be coordinated and controlled, and the real-time and bandwidth requirements for data transmission are high. The PROFIBUS protocol and industrial Ethernet protocol of Siemens PLC can meet these requirements and achieve efficient control of the entire production process. In some application scenarios with extremely high real-time requirements, such as robot control and high-speed production lines, the industrial Ethernet protocol of Siemens PLC can provide extremely low communication delays to ensure efficient operation of the system. In addition, the communication protocol of Siemens PLC also has good compatibility and stability, and can communicate efficiently with equipment from different manufacturers to ensure the normal operation and reliability of the system.
VIII. Hardware performance and scalability comparison
8.1 Siemens hardware has strong performance
8.1.1 Powerful processing capability
Siemens PLC uses high-performance processors with fast computing speed, and can quickly process a large number of control tasks and data. According to statistics, the processor speed of Siemens S7-1200 PLC can reach 100 MHz, while the processor speed of S7-1500 PLC is as high as 1 GHz. At the same time, Siemens PLC is equipped with large-capacity memory, which can store a large amount of programs and data. For example, the working memory capacity of S7-1500 PLC can reach 300 MB, and the loading memory capacity can reach 1 GB. Such processing power enables Siemens PLC to cope with complex industrial control scenarios, such as automation control of large production lines and construction of smart factories.
8.1.2 Good scalability
Siemens PLC performs well in hardware scalability. It supports a variety of expansion modules, such as digital input and output modules, analog input and output modules, communication modules, functional modules, etc. Users can choose appropriate expansion modules according to actual needs and flexibly expand the functions of PLC. For example, when the number of input and output points needs to be increased, digital input and output modules can be added; when analog signals need to be processed, analog input and output modules can be added. In addition, Siemens PLC also supports distributed I/O systems, which can distribute input and output modules in different locations and connect them to the PLC controller through the network to achieve remote control and data acquisition. This scalability enables Siemens PLC to adapt to industrial control systems of different sizes and complexities.
8.2 Mitsubishi hardware has characteristics
8.2.1 Some functions are outstanding
Mitsubishi PLC has characteristics in some hardware functions. For example, the high-speed counter instruction of Mitsubishi PLC is more convenient than Siemens, and can count high-speed moving objects quickly and accurately. In some application scenarios that require high-speed counting, such as packaging machinery, printing machinery and other industries, the high-speed counter instruction of Mitsubishi PLC can play an important role. In addition, the input and output modules of Mitsubishi PLC have various types, such as transistor output, relay output, thyristor output, etc., which can meet different control needs.
8.2.2 Minicomputers have advantages
Mitsubishi minicomputers have advantages in some aspects. Mitsubishi mini PLCs are small in size, light in weight, easy to install, and suitable for application scenarios with limited space. For example, in some small automation equipment, laboratory equipment and other fields, Mitsubishi mini PLCs can provide efficient control solutions. At the same time, Mitsubishi mini PLCs are relatively low in price and cost-effective, making them a good choice for some users with limited budgets. In addition, the programming software of Mitsubishi mini PLCs is simple and easy to use, with low learning costs, which is very convenient for beginners.Easier to get started.
9. Application scenarios and selection suggestions
9.1 Mitsubishi applicable scenarios
9.1.1 Advantages of motion control
Mitsubishi PLC has significant advantages in motion control scenarios such as robots. Due to its rich instructions and dedicated positioning instructions, it can easily achieve precise control of the manipulator and complete various complex actions. For example, in the assembly line of the automobile manufacturing industry, the robot needs to perform fast and accurate grabbing, handling and assembly actions. Mitsubishi PLC can achieve efficient control of the robot through its powerful motion control function. According to statistics, in some automobile manufacturing companies, the action accuracy of manipulators controlled by Mitsubishi PLC can reach ±0.1mm, which greatly improves production efficiency and product quality.
9.1.2 Strengths of positioning control
Mitsubishi PLC is also strong in servo or step positioning control. Its positioning function block has the characteristics of high precision, fast response, flexible adjustment, multi-axis control and high reliability. For example, in the electronics manufacturing industry, precise positioning and drilling operations on circuit boards are required. The positioning function of Mitsubishi PLC can achieve precise control of the servo motor to ensure the accuracy of the drilling position. At the same time, Mitsubishi PLC's QD70 positioning module encapsulates functions such as JOG, HOME and absolute positioning into sub-modules FB. Programmers can implement the required positioning functions with simple calls, greatly simplifying the program development and maintenance process.
9.2 Siemens applicable scenarios
9.2.1 Strengths of process control
Siemens PLC has excellent performance in process control, especially suitable for simulation of central air conditioning, sewage treatment, temperature control, etc. Volume processing scenarios. Siemens' analog modules are cheap, have simple programs, and can process a large number of analog signals quickly and accurately. For example, in the central air-conditioning system, multiple analog parameters such as temperature, humidity, and pressure need to be monitored and controlled in real time. Siemens PLC can achieve efficient control of the central air-conditioning system through its powerful process control function. According to statistics, the temperature control accuracy of central air-conditioning systems controlled by Siemens PLC can reach ±0.5°C, which greatly improves the comfort of the indoor environment.
9.2.2 Advantages of communication collection
Siemens PLC has advantages in communication collection and is suitable for scenarios where a lot of instrument data needs to be collected. Siemens PLC supports a variety of communication protocols, such as PPI, MPI, PROFINET, OPC UA, etc., and can communicate efficiently with various instruments. For example, in a sewage treatment plant, multiple parameters such as water quality, flow rate, and pressure need to be monitored in real time. Siemens PLC can collect and process various instrument data through its powerful communication function. At the same time, with the help of HiWoo Box industrial IoT gateway, Siemens PLC can realize rapid data collection and remote monitoring, improving production efficiency and management level.
9.3 Reasonable Suggestions
9.3.1 Use its strengths to avoid its weaknesses
When enterprises choose PLC, they should reasonably choose Mitsubishi or Siemens PLC according to different control methods and give full play to their respective capabilities. the strengths and avoid the weaknesses. For example, if the company's equipment is mainly for motion control and positioning control, then you can choose Mitsubishi PLC; if the company's equipment has a lot of analog quantities to process or requires communication collection, then you can choose Siemens PLC. Only in this way can efficient control be achieved and production efficiency and equipment reliability improved.
9.3.2 Comprehensive consideration of actual needs
When choosing a PLC, companies also need to consider factors such as performance, software programming, reliability and after-sales service . In terms of performance, companies need to choose a PLC with sufficient processing capabilities and input and output points based on actual control needs. In terms of software programming, companies need to choose PLCs that are simple to program and easy to maintain. In terms of reliability, companies need to choose PLCs with high stability and reliability to ensure long-term stable operation of equipment. In terms of after-sales service, companies need to choose suppliers with good after-sales service to ensure that they can receive timely repair and support when equipment fails. In short, when enterprises choose PLC, they need to comprehensively consider various factors and choose the PLC that best suits them.