Input Module plc's shortcomings

input module plc Disadvantages: module mechanism to bring safety hazard 

1, the intercept system calls. 

2, modify the output symbol table. 

3, by modifying the system calls the plc temperature module‍ themselves hidden. 

4, redirect file operations. 

5, modify the file owner. 

6, plc controller suppliers‍ processes. 

7, the executable file redirection. 

8, calling sys_socketcall by modifying the system, making the system after receiving the specified data packet open the back door 

9, TTY hijacking. 

10 virus.‍

Output modules plc explanation

output module plc, known as members, is a collection of individually named and independently able to complete certain functions of plc program logic controller‍ statements (ie, aggregate program code and data structures). It has two basic characteristics: internal features and external features. Wherein the external plc digital input output module‍ module with means to contact the external environment (i.e., program modules or other way to call the module, including input and output parameters, global variables referenced) and functional modules; internal environment is the internal characteristics of the module having the characteristics (i.e., the local module data and program codes).

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plc io module is divided into several modules by function

plc IO module is divided into several modules according to function, such as CPU modules, input modules, output modules, power modules, and so on. The module features a communication modules plc‍ mainframe is more some kind of modules and therefore relatively more. This can also be said to be the trend. At present, some medium-sized machine, the module features also tend to single species also increases Township. If the same OMRON Corporation intelligent plc‍ series PLC, H machine CPU unit to contain the power, and put the power ceded Ha machine, a separate power supply module.

the role of input and output modules plc

PLC input module for receiving the various parameters of the production process. (Start and stop with the input) 

PLC output module for programmable controller plc communication modules‍ after sending the information obtained and completed by plc intelligent controller‍ control industrial site outside the machine actuators. (Execution results with output) 

1 have a good anti-jamming capability. 

2 to meet the matching requirements of various types of industrial field signals‍

PLC input module wiring is correct

PLC control system design, plc digital input output module‍ a smaller proportion of total wiring work, most of the work or the PLC programming design work, but it is the basis for the design of programming, as long as the wiring is correct, can be programmed to plc programmable logic controller‍ smoothly. And to ensure the correctness of the wiring work, it must be inside the PLC input and output circuits have a more clear understanding.

Circuit relay output module plc

Relay output module plc circuit, the internal iron 1.4016 steel 2r of the relay coil is energized, its normally open contacts closed, the external load electrical work. Meanwhile relay power from the isolation and amplification, each way just to provide users with a pair of stainless steel coils open contacts. With contacts parallel RC circuit and varistor to eliminate Tun arc generated when the contact is opened, in order to reduce the interference of its CPU.

The collector of transistor output module plc circuit

The collector of transistor output module plc circuit that outputs a signal to the internal circuit of the output latch, and then sent via the analog output plc output transistor, which is saturated conduction state and the off state corresponds to the turning on and off the contacts opened. Figure regulator to suppress over-voltage shutdown and external surge plc communication module to protect the transistor, the transistor output circuit delay time <1ms. The output circuit of the transistor structure of the output circuit of the FET is substantially the same.