Do you have a Siemens S7-300 Programmable Logic Controller that you are unfamiliar with but need to program NOW! The following is a quick set of instructions I’ve put together to help you get started programming a Siemens S7-300 PLC.
After loading the programming software and connecting a Siemens MPI cable between your programming computer and the PLC, open the SIMATIC Manager by clicking the icon on the desktop. The STEP 7 Wizard window opens: “New project”. It’s easier to use the Wizard to set up communications with your PLC, but I chose to take the scenic route. I thought I would learn more this way. Therefore, close the STEP 7 Wizard window by clicking Cancel. If there are other windows or projects open, close them. We want to start with a totally new program.
Create a new project by clicking the new project button on the toolbar in the upper left corner of your screen.
The New Project window opens. Here you will see all the existing programs located on your computer. Near the bottom of the window, you’ll see the Name: input form. Type the name you want for your new project and click OK.
A new window will open showing your project name at the top. You will also see your project in the window on the left side of the screen at the top. Right click on your project and choose “Insert New Object”. Choose the device to program. We will be using the SIMATIC 300 drop, so choose that selection.
You will now see SIMATIC 300 appear in the right window of your screen. It should be highlighted in blue. Click anywhere in the window to make the blue disappear. Double click SIMATIC 300 and it will move to the left window and “Hardware” will appear in the right window.
Double click on “Hardware” and two (maybe three) new windows will open. On the left will be SIMATIC 300 – (your project name). The window on the right will be the parts catalog.
Look in the window on the right, the parts catalog, and click on the plus sign next to SIMATIC 300.
Click the plus sign next to RACK – 300. Click and drag the Rail to the window on the left. You will now see the Slots window appear. This is where we will place our PLC components.
First we will choose our CPU. Looking at the parts catalog, in the SIMATIC 300 tree, choose the CPU you are using. We are using CPU – 300, so click the plus sign next to that option.
Now look at the top left front of your PLC. This is where you will find the PLC model. I will use CPU313C-2 DP as an example since this is the PLC model I use.
Find this CPU in your parts catalog and click the plus sign. You will now see some part numbers.
Look back at your PLC. Locate the door that covers the MPI port. This will be the lower left side of the PLC. On the bottom of the door you will find the part number. The PLC part number I’m using as an example is 313-6CF03-0AB0.
Find this part number in the parts catalog. You will notice that this is another folder. Open it and you will see V2.0 and V2.6. Look at the PLC again, open the door covering the MPI port, and just above the MPI port you will see V2.6.3.
Go back to the parts catalog and click on V2.6. Notice how a slot in the left window will be highlighted in green. I think it will be slot #2. (Slot #1 is reserved for power supplies.) This is where you will drag and drop your CPU. (Note that the software will not allow you to put the CPU in any slot other than slot #2.)
When you release the mouse button over slot #2, a new window will open, “Properties – PROFIBUS Interface”. Click new, a new window opens, click OK, and then click OK again. We are not setting up a network at this time.
You will now see your CPU and associated hardware listed.
Double-click the slot that lists your DI16/DO16 (digital input/digital output).
A window with three tabs will open. The first tab will be General, the second tab will be Addresses, and the third tab will be Tickets.
Open the “Addresses” tab. We need to change the default addresses. Do this by unchecking the System Default button and changing 124 (or whatever address you have) to 0. Do this for both inputs and outputs.
Now we need to change the address of the node. Return to the window where you double-clicked on DI16/DO16 and double-click on slot 2, the CPU 313-2DP slot.
The Properties – CPU 313C-2DP window opens.
Look down the window a little more than halfway and find the Interface area and click Properties. Another window will open, “Properties – MPI Interface CPU 313-2DP”.
Change the address to meet your specific criteria. I know that my laptop, which I am using to program my PLC, is always addressed as 1 and my target PLC is usually addressed as 2. It will probably be the same.
Now click on MPI (1) and click OK. Click OK again to close the Properties window.
Save and compile by clicking the icon located on the left of the toolbar.
Download the hardware configuration to the PLC by clicking the download icon located on the toolbar.
A window titled “Select Target Module” should open. Click OK.
Another window titled “Select Node Address” will open. You should see your node address for the PLC you are working with as you set it in a previous step. If not, click view and click any node address that appears and click OK.
Go back to the SIMATIC Manager (by clicking on the tab on the taskbar).
Click Options. Select Set PG/PC interface. Choose PC Adapter (Automatic).
Click Properties. A new window will open showing Automatic Bus Profile Detection or Local Connection. Click on Local Connection and choose USB. Now choose Auto Bus Profile Detection and change the address to 30. You can check your connection now by clicking Start Network Discovery. If a new window opens showing Network Type = MPI, Baud Rate = 187.5 kbps, you have established communication with your S7-300. Click Close. Click OK. Click OK.
Now is the time to start programming. Looking at the SIMATIC Manager window, click the plus sign next to SIMATIC 300(1), click the plus sign next to CPU 313C-2DP, click the plus sign next to S7 Program( 1). Now click on Blocks and you will see the system data and OB1 appear in the right window of your screen.
Double click on OB1 and a new window will open called Properties – Organization Block
Here you can choose how you want to program, in LAD (ladder), STL (instruction list) or FBD (function block diagram). Choose which one you want to use and click OK.
Double-click OB1 again and the LAD/STL/FBD programming window will open.
Now you can start programming.
I have these same instructions with pictures on my website at http://www.saturdayafternoonhobbies.com
