The level of system design will directly affect the performance of the control system and the reliability of the equipment. Among them, the selection of PLC is very important. How to choose a suitable PLC according to different control requirements, and design a control system with stable operation, reliable operation, safety and practicality, convenient debugging, and easy maintenance? In the design of the PLC system, the system plan should be determined first, and the next step is the design selection of the PLC. Select PLC, mainly to determine the PLC manufacturer and PLC specific models. For a system solution that requires distributed systems and remote I/O systems, the requirements for networked communications must also be considered. So how should choose PLC? A PLC manufacturer's choice Determine the manufacturer of the PLC, mainly should consider the requirements of the equipment user, the designer's familiarity with the different manufacturers of PLC and design habits, the consistency of supporting products and technical services and other factors. Considering the reliability of the PLC itself, as long as it is a product of a large foreign company, there should be no problem of poor reliability. In addition, for some special industries (such as: metallurgy, tobacco, etc.) should choose to put into operation in the relevant industry sectors, mature and reliable PLC system. Two input and output (I/0) points estimate The number of PLC input/output points is one of the basic parameters of the PLC. The number of I/O points should be determined based on the sum of all the input/output points required to control the equipment. In general, the PLC I/O point should have a proper margin. Usually based on the statistics of the number of input and output points, and then increased by 10% to 20% of the expandable margin, as the input and output points estimated data. In the actual ordering, the input and output points need to be adjusted according to the product features of the manufacturer's PLC. Three estimates of PLC memory capacity The memory capacity refers to the size of the hardware memory unit that can be provided by the PLC. The memory capacity of various PLCs can be found in the basic parameter table of the PLC. For example, the user program memory capacity of Siemens S7-314 PLC is 64 KB. , S7-315-2DPPLC user program storage capacity of 128KB. The program capacity is the size of the memory unit used by the user program in the memory, so the memory capacity should be greater than the program capacity. At the design stage, because the user application has not yet been compiled, the program capacity needs to be estimated. How to estimate the program capacity? Many literatures give different formulas, which are generally 10 to 15 times the number of digital I/O points, plus 100 times the number of analog I/O points. This number is used as memory. The total number of words (16 digits is a word), and the remaining 25% of the number is taken into account. Four PLC communication function choice The communication function of PLC is more and more powerful now, a lot of PLCs all support many kinds of communication agreements (some need to equip the corresponding communication module), when choosing, should choose the appropriate communication way according to actual need. The main forms of the PLC system's communication network are the following: (1) The PC is the main station, and multiple PLCs of the same model are slave stations to form a simple PLC network; (2) 1 PLC is the master station, other PLCs of the same model are slave stations, constitute the master-slave PLC network; (3) The PLC network is connected to a large DCS as a subnetwork of the DCS through a specific network interface; (4) Dedicated PLC network (dedicated PLC communication network for each manufacturer). In order to reduce the CPU communication tasks, according to the actual needs of the network composition, communication processors with different communication functions (such as point-to-point, field bus, industrial Ethernet, etc.) should be selected. Five PLC model selection PLC type: PLC is divided into two types according to the structure of integral type and modular type; overall type PLC has fewer I/0 points and is relatively fixed, so the user has less room for selection and is usually used for small control systems. Representatives of this type of PLC are: Siemens' S7-200 series, Mitsubishi's FX series, and Omron's CPM1A series. The modular PLC provides a variety of I/O modules that can be plugged into the PLC base to facilitate the user's selection and configuration of the I/O points of the control system as needed. Therefore, the configuration of the modular PLC is more flexible and is generally used for large and medium-sized control systems. For example, Siemens S7-300 series and S7-400 series, Mitsubishi's Q series, Omron's CVM1 series. Six I/O Module Selection (1) Selection of digital input and output modules The selection of digital input and output modules should take into account the application requirements. For example, for the input module, application requirements such as input signal level and transmission distance should be considered. There are many types of output modules, such as relay contact output type, AC120V/23V bidirectional thyristor output type, DC24V transistor-driven type, and DC48V transistor-driven type. Usually the relay output output module has the advantages of low cost, wide range of use voltage, but the service life is shorter, the response time is longer, and the surge absorption circuit needs to be added when used for inductive loads; the response time of the bidirectional thyristor output type module is faster. Applicable to frequent switching, inductive low power factor load occasions, but the price is more expensive, less overload capacity. In addition, the input and output modules can be divided into 8 points, 16 points, and 32 points according to the number of input and output points, and they must be properly equipped according to actual needs when selecting. (2) Selection of analog input/output module Analog input modules, according to the analog input signal types can be divided into: current input type, voltage input type, thermocouple input type. The current input type usually has a signal level of 4 to 20 mA or 0 to 20 mA. The voltage input module usually has a signal level of 0 to 10 V, -5 V to +5 V, and the like. Some analog input modules are compatible with voltage or current input signals. The analog output module is also divided into a voltage output module and a current output module. Current output signals usually have 0-20 mA and 4-20 mA. Voltage type output signals usually have 0 to 10V, -10V to +10V, and so on. Analog input and output modules can be divided into 2 channels, 4 channels, and 8 channels according to the number of input and output channels. Seven functional modules Function modules include communication module, positioning module, pulse output module, high-speed counting module, PID control module, temperature control module and so on. When selecting a PLC, the possibility of matching to the functional module should be checked. Selecting a functional module involves both hardware and software. In terms of hardware, first of all, it should be considered that the function module can be easily connected to the PLC. The PLC should have related accessories, installation locations and interfaces, and connection cables. In software, the PLC should have corresponding control functions, which can facilitate the programming of function modules. For example, Mitsubishi's FX series PLCs can conveniently control corresponding function modules through the "FROM" and "TO" commands. Eight general principles After the PLC model and specifications are roughly determined, the basic specifications and parameters of each component of the PLC can be determined one by one according to the control requirements, and the model number of each component module is selected. When selecting a module model, follow these guidelines. (1) Convenience: As a general rule, as a PLC, there are many types of modules that can meet the control requirements. The selection should be based on the principles of simplified circuit design, ease of use, and minimization of external control devices. For example: For the input module, the input form that can be directly connected with the external detection element should be selected preferentially to avoid using the interface circuit. For the output module, priority should be given to the output module that can directly drive the load, minimizing intermediate relays and other components. (2) Versatility: When selecting models, it is necessary to take into consideration the unity and universality of each PLC module and to avoid excessive types of modules. This will not only be conducive to procurement, reduce spare parts, but also increase the interchangeability of the various components of the system, to facilitate the design, commissioning and maintenance. (3) Compatibility: When selecting the PLC system components, compatibility should be fully considered. In order to avoid the problem of poor compatibility, the manufacturers of the main components that make up the PLC system should not be excessive. If possible, try to choose the same manufacturer's product. 5.00MM Wire To Board Connectors
5.00MM Wire To Board Connectors
5.0mm Wire to Board connectors are avialable in different terminations and sizes intended for use on a variety of applications. These connectors provide power and signal with different body styles, termination options, and centerlines. To find the wire to board set required, click on the appropriate sub section below.
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5.0mm Terminal
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Pitch 5.0mm Wafer Right Angle&SMT Type