PLC input modules are used to detect incoming field input signal and converts the input signal within the PLC accepts low-voltage signal. 1. Input signal type and voltage selection switch input signal types there are three types of modules: DC input and AC and AC/DC input. General according to the input signal and the surrounding environment … Continue reading How to choose PLC switch input module?
PLC digital output module selection
Output modules are PLC internal low voltage signal can be converted to an external output device required to drive signals. Main load voltage should be considered when choosing the type and size, system requirements, to delay load state changes are frequent, and so on. 1. Choice of outputDigital output modules have three output: relay output, transistor … Continue reading PLC digital output module selection
485 communication grounded? How should the grounding?
According to long-term engaged in the items technology work of Comrade told: ① RS485 communications short distance (800m within) of General can using no shield of General double twisted line II interference more heavy Shi can using with shield layer of double twisted line (shield layer empty hanging/or only end grounding--to and "strong electric to" … Continue reading 485 communication grounded? How should the grounding?
RS232 serial interface basics
Now more commonly used RS232 serial 9-pin d-shaped serial [DB9] and 25-pin d-shaped serial [DB25], the maximum communication distance of up to [15m]. The short distance between two devices close, 232 of them with 232 cable directly connected to the serial port if distant, via modem (MODEM) connected.RS232 interface-"Negative logic"--the output is represented by +5V~+15V … Continue reading RS232 serial interface basics
Basic instruction of PLC system features
PLC programming languages and computer languages, have distinctive features, which is different from a high-level language, and with the General Assembly, it is both easier to write, and to meet the requirement to debug. At present, there is no programming language to the manufacturers of products are compatible. If Mitsubishi products has its own programming … Continue reading Basic instruction of PLC system features
CNC machine tools PLC hardware electrical interface
CNC machine tools PLC consists of two types of interface information, namely electrical interfaces of the hardware information and register the software interface information.1. the signal flow including input and output interfaces2.From the signal amplitude characteristics including analog and switch interfacesInput signal: composed of machine transfer signals to the PLC or CNC external device known … Continue reading CNC machine tools PLC hardware electrical interface
PLC industrial control selection methods
When the PLC system is designed, first determine the control scheme, the next step is the design of PLC type selection. Characteristics of process design and application requirements are the main basis for selection. PLC and related equipment should be integrated, standard, as easy to form a whole and industrial control system, easy to extend … Continue reading PLC industrial control selection methods
PLC overall composition and characteristics
This section of the PLC of the structure and characteristics of the hot issues of the solution, so that beginners PLC has an overall knowledge.Q: what is a PLC (programmable logic controller)?Answer: PLC can series program device (Programmable Logical Controller) is a digital operation operation of electronic system, designed for industrial environment Xia application and … Continue reading PLC overall composition and characteristics
Process and characteristics of PLC program
1. Input sample stageEnter the sampling stage, PLC to scan works in order to sample all inputs input state and stored in the input image register, input mapping registers to be refreshed. Then enters the processing stage, during the program or other phases, even if the input state changes, enter map registers of will not … Continue reading Process and characteristics of PLC program
The characteristics and advantages of field bus
1. comparison of the DCS and FCSAs shown in Figure 7-28, FCS has broken the traditional DCS (distributed control system) structure. DCS in the field devices and controllers are located in the control room one physical connection. FCS uses a smart device, DCS in the control room of the original control modules, input/output modules in … Continue reading The characteristics and advantages of field bus
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