Hello everyone, I am a industrial control amateur, my name is Wang Jiayang. When you come into contact with Siemens PLC programming, you can learn from the work, but many places can't be done independently. The knowledge points of learning are not able to connect, and I will have a professional training institution system for the family. Thunder, after I learned the work control, I will make a decision, please study, report my thoughts to the company, the company leaders are very supported, not only approved my review, but also funded me to learn to improve skills, I chose is Siemens' class, including Siemens S7-200 SMART, and 300/400 Boap Advanced Class. Now, I have completed the study of Smart's basic class. After a month study, I have a comprehensive understanding of Smart. The content is very suitable for beginners, and the advanced application of the back is very comprehensive. Next, I will enter the 300/400 learning. Use the weekend to show me my learning results, share an example of MODBUS communication using WinCC implementation and SMART to manipulate MODBUS communication of Smart and inverters.
First, first we need a 200smart PLC, a 485 interface, 2 1.5 square cable, a network cable, 2 inverters, a computer.
Second, here I use 2 British Witch Teng's inverter, just connect the 485 communication terminals of the two inverters, negatively negative negative, and the No. 3 needle of the PLC485 interface (3 positive, 8 Negative), link PLC and computers with a network cable. Figure:
Third, after the hardware connection is completed, we start writing a communication program:
1: Hardware configuration (Communication function only, no consider the power failure, no setting).
2: Write a program:
The first step: power-on initialization procedure.
Step 2: Call the MODBus library for communication initialization.
Step 3: Use the initialization completion bit M0.0 delay 100MS to trigger the first communication command, the content is: write the value of VW0 to the 1st station is 2000H register (2000h is 16), it needs to be converted into a decimal 40001 and then converted to 16 into the 16 # bc41).
The figure below shows the communication register address list of the inverter, and the value of the VW0 is 0001-0008 and corresponds to its corresponding function.
2001h converts the frequency address to the 16-way address is BC42
The figure below shows the No. 1 frequency setting: write the value of VW2 to 2001h.
The programs of the second stop are the same. Figure:
Then the following program is controlled: because the decimal 1-8 and hexadecimal is the same, I have not written 16 #.
The program is written to the PLC after downloading.
Step 4: Create a project with PC Access Smart.
Create a new PLC set its address to 192.168.2.1, then create a variable as follows:
Create m1.0 to m1.3 and VW14 VW18 session. As shown below
Then click Save.
Step 5: Open WinCCV7.3 Create a single user project. Right-click on variable management, select OPC in variable management
Select system parameters.
Click to browse the server
The variable created in PC Access is added to WinCC.
After the addition, the AS-OS-OS value of PL1 and PL2 is determined later.
Then create a new screen in the WinCC's graphics editor, as shown below:
Set the parameter setting of each graph to the corresponding variable link, save the click activation.
Fourth, adjust the parameters of the inverter. First initialize its parameters first.
Then set
P00.01 is 2
P00.06 is 8
Adjust the communication parameters:
P14.00: The frequency converter address is 2, 2.
P14.01: 3 baud rate is 9600.
P14.02: 1 Doll checks a stop bit.
Other parameters default.
After the setting is complete, you can control the start, stop, and frequency of the two inverters in WinCC. Up to 32 inverters can be controlled simultaneously. , Read full text, original text title: Graphic explains the Modbus Communication of Siemens S7-200SMART!
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