Siemens plc learning notes 3 (S7-300 signal module)

S7-300 PLC Siemens

This is the second video study note of Yang Shengfeng.

1. Digital Volume Module

1) Digital Volume input module

The digital input module converts the Digital Signal levels sent during the field process to the internal signal levels of the S7-300.

A. Digital Input module sm321 (external 24 V power supply required)

Sm321 has four types of modules: DC 16-point input, DC 32-point input, AC 16-point input, and AC 8-point input.

Figure:

B. Digital output module sm322 (external 24 V power supply required)

The digital output module sm322 converts the internal signal level of the S7-300 to the external signal level required by China, which can be directly used to drive solenoid valve, contactor, small motor and motor starters.

The transistor output module can only carry DC Load and belongs to the DC output module;

The Thyristor output mode belongs to the AC output module;

The module of the relay contact output mode belongs to the AC/DC dual-purpose output module.

In terms of response speed, the transistor responds the fastest and the relay responds the slowest. In terms of safety isolation effect and application flexibility, the output type of the relay contact is the best.

Figure:

C. Digital I/O module sm323 (external 24 V power supply required)

The sm323 module has two types: 8 common input and 8 common output, 16 common input and 16 common output. The two features are the same. I/O rated load voltage 24vdc, input voltage "1" signal level is 11 ~ 30 V, "0" signal level is-3 ~ + 5 V, I/O is isolated from the backplane bus by optical coupling. Under the rated input voltage, the input delay is 1.2 ~ 4.8 Ms. The output has the electronic short circuit protection function.

Figure:

2) analog modules

A. analog input module sm331 (external 24 V power supply required)

The analog input (AI) module sm331 currently has three types, namely, 8ai * 12 module, 2ai * 12-bit module, and 8ai * 16-bit module.

Sm331 is mainly composed of A/D conversion makeup, analog switching switch, compensation circuit, constant current source, photoelectric isolation component, logical circuit, etc. A/D conversion makeup is the core of the module, and its conversion principle adopts the integral method. The precision of the measured analog quantity is the positive function of the Set integral time, and the longer the integral time, the higher the accuracy of the tested value. Sm331 can be used for four-point time: 2.5 ms, 16.7 ms, 20 ms, and 100 ms. The corresponding values are 8, 12, 12, and 14.

 

B. analog output module sm332 (external 24 V power supply is required)

It is used to adjust the output speed of the level generator and the opening of the regulating valve.

C. analog input/output module sm334 (external 24 V power supply is required)

Used to connect analog sensors and connectors.

3) Representation of simulated values

The S7-300's CPU uses a 16-bit binary complement to represent a simulated value. The highest bit is S, "0" indicates a positive value, and "1" indicates a negative value. The accuracy of the tested value can be adjusted, depending on the performance of the analog module and Its set parameters, for analog values with an accuracy of less than 15 bits, digits with low power in low bytes are not needed.

Note: The bits after 1 in the figure are not used.

4) Upload several configuration maps for using the SM module in your project.

Siemens plc learning notes 3 (S7-300 signal module)