Explain the key points of learning Siemens PLC

Learning Siemens PLC is not as difficult as you think. It can be summarized in one sentence: for beginners, it is enough to roughly grasp the hardware composition, programming software, system instructions and program structure of PLC!

Next, let us explain the key points of PLC learning one by one.

1. Model selection and cost

Recommended: SR20

Reason for recommendation: This starts with the Siemens PLC product family.

Siemens has been making PLCs for more than 40 years, and its latest product family is SIMATIC S7.

Siemens has launched different product series to meet different market demands, such as the high-end S7-1500 series, the mid-range S7-1200 series, and the low-end S7-200 SMART (hereinafter referred to as SMART) series.

For beginners, it is best to start with the SMART series.

SMART is a new generation of PLC developed by Siemens for the Chinese market. It is widely used in packaging, textiles, machine tools, food, subways and many other fields.

It can effectively improve equipment performance and reduce costs, and is very cost-effective and reliable.

SMART is mainly divided into two series, ST and SR, both of which can be purchased on e-commerce platforms. The main differences between the SR series and the ST series are:

The ST series can receive/output high-speed pulse signals, so the ST series can be used in motion control, common packaging production lines, currently popular robotic arms and other fields.

These functions are generally not applicable during the learning stage.

Moreover, there is no difference between ST and SR in programming and usage, and it is very easy to communicate between them.

In the SR series, for beginners, I recommend SR20 for the following reasons:

1. High cost performance, it can be purchased from Siemens dealers on major e-commerce platforms, and the price is only more than 600 yuan

2. Configuration software is free, and learning and migration costs are low

The configuration software of the SMART series (i.e. the host computer in the popular sense) is STEP 7-Micro/WIN SMART (Micro/WIN for short), which can be downloaded and used for free on the official website.

The design concept of Micro/WIN is consistent with the configuration software TIAPortal of the other two high-end PLC series, S7-1200 and S7-1500 mentioned above, and it also supports communication between S7-1200 and S7-1500.

If you need to learn Siemens' mid-to-high-end PLC product series in the future, the cost of learning and migration is very low.

The true face of SR20 PLC

Next, let’s take a look at the appearance of SR20 PLC.

The blue line is the network cable for communication between Micro/WIN and PLC.

The upper row of terminals are signal input terminals and power supply terminals.

The row of terminals below are the output terminals and the power supply terminals for the expansion modules.

At the lower left is the RS485 interface.

There is also some identification information on the left and right sides, such as order number, FS number, etc.

2. Introduction to PLC

PLC is a highly integrated system. In actual work, only some of its functions may be used, but when learning, you need to have a comprehensive understanding of the functions of PLC.

SMART PLC is a very good introductory series. As we mentioned earlier, the operating tool of SMART PLC is Micro/WIN.

So learning SMART PLC is learning Micro/WIN.

We also exchange learning experiences about SMART PLC internally, and the general feeling is that the learning cost of the SMART series is very low.

When designing the functions of SMART PLC, we take ease of use as the primary consideration. Even if you have no programming experience, you can become familiar with most of the functions of PLC products in a short time.

High cost-effectiveness, easy to use and reliable, this is one of the reasons why the SMART series is so successful in China.

At this time, some fans will ask, "I don't know anything. Even if PLC is very simple, I can't learn it!" Don't panic, and look at the good stuff I have for you below!