How to connect and Download Program on S7-300 PLC?

An Overview of S7-300 PLC?

The SIMATIC S7-300 universal controller saves assembly space and features a modular design.

A wide range of modules may be used to centrally extend the device or to build localized systems, depending on the job at hand, and to enable the cost-effective storing of spare parts.

Strong, lightweight, and cost-effective.

SIMATIC is known for its consistency and efficiency.

How to Connect with PC?

Step 1) Open Micro/Win software and Click the RUN icon on the toolbar or Choose the

PLC-> RUN menu command

Step 2) Click OK to change the operating mode of the S7-300 PLC.

Note: When the S7-300 is in RUN mode, the output LED is in RUN mode, the output LED for Q0.0 is turned on and off when the S7-200 is running the program.

Step 3) Click on PG/PC Interface

Step 4) Click on PC/PPI and local connection and choose COM4

Step 5) Click on communication tab

Step 6) In the Access Path, select PC/PPI cable (PPI). a) Click the Properties button.

Step 7)

a)Assign the station address (#0 is assigned for this test)

b) Set the transmission rate at 9.6kbps

c) Highest node address is 31

d) Click the OK button to exit from the Properties dialogue box

Step 8) Now, create a simple logic by clicking on the normally open contact/output coil

Step 9) Select Download option

Note: Follow all settings in the Download dialog box

How to download Program to S7-300 using Simatic Step 7?

Step1) Open SIMATIC Manager and click on the “new” icon to create a new project.

Note: In this window, we insert a name for our project in the “name” field. The route to our saved project is displayed in the “storage location.” And we can change the default location to our wish.


Step 2) Click on Insert → station–> Simatic300.

Step 3) After selecting “Station 300,” we could see that a subgroup called “SIMATIC 300” has been created for our project.”

Step 4) Then Click on “Simatic 300” and it takes us to the hardware so that we can configure the modules we need for the PLC. Here we are using “S7 300” PLC so we have to select the desired modules from “SIMATIC 300” subgroup.


Step 5) First of all, we need a rack in which the modules are mounted. To attach the rack, open the “Rack 300” and double click the “Rail” to connect it to the left pane. As you can see, this rack has 11 slots.

Step 6) To power on and turn on our PLC modules we need to connect a “Power Supply” in the first slot. To do this, we open the “PS300” folder and double-click on these two amber power supplies to insert them into the first slot of the rack.


Step 7) In the second slot of the rack, we often mount the “CPU” module. To select the desired module, we open this “CPU 300” folder, which opens to reveal all types of “300 CPUs”.

We need to select “316 CPU”, so we have to open the “CPU 316: folder and select the appropriate part number to insert it into the slot second in the rack. We can add the remaining modules in this way.

Step 8) The addresses of the digital input module vary from byte zero to byte number one means that the addresses we will use for our program in this module begin at “I 0.0” for the first input and proceed to “I 1.7” for the final input.

You will now see the addresses of our digital output module varying from byte number 4 to byte number 5 so that there are 16 addresses that we can use for this module starting from “Q 4.0” to “Q 5.7.” Finish the setup and download it to the PLC

Step 9) Click on the save and compile icon to save it before downloading. then we select the download icon. This will open a window where we need to pick the CPU on which we want to download the device, and then press “OK.”


In the next window, press “view” and then pick the required “MPI” address, and the configuration will be downloaded to the CPU after pressing “OK.”

Now that the setup has been done, we will search the project tree and see that a subgroup of the same name as the CPU has been added there.

Step 10) Now we can write our program in a file called "OB 1′′ We can find “OB 1” by opening the “S7 Program” folder and searching in the “Block” folder.

Step 11) Double-click on “OB 1” to open it. This “Properties” window opens as we first opened it. We all have no problem in the window to enter the world of programming

Step 12) Open the symbol table from the options menu to indicate the representative name for each I/O and save the symbol table.

Step 13 ) Make the PLC program as per your project requirement.

Step 14 ) To download the program into PLC click on the Download button