8.1.1 Installing the Software
2. Examine the contents of the software box. There should be manuals for the software and the PLC. There should also be a CDROM and a floppy disk. You will also find quick reference cards, training information, etc.
8.1.2 Connecting The Hardware
2. Connect the provided power cord. Plug the PLC in, turn it on and look to see if the power light turns on. Turn off the PLC before the next step. NOTE: the power is wired directly to the PLC L1, L2/N and ground terminals on the front of the PLC.
3. The communication cable has two connectors. The round connector plugs into the front of the PLC: there is a small door on the left hand side. The other end of the cable should plug into the back of the computer. This will either be in ‘COM1’ or ‘COM2’. Chances are if there is a serial mouse attached to the computer, it will be ‘COM2’. If you are not sure, you can try both later.
8.1.3 Running the Software
1. Move the mouse to the bottom left corner of the screen to where the “Start” button is located and click once. Next, click on “Programs” then “Rockwell Software”, then “RSLogix 500 English”, and finally “RSLogix 500 English”.
3. Select ‘File’-’New’ and then select the processor ‘Micrologix 1000’. Next, change the driver to ‘AB_DF1-1’. This may cause the software to start the RS-Linx program: if it does go to step 4, if not go to step 5.
4. (If RS-Linx has started and is on the screen) Go to ‘Communications’-’Configure Drivers...’-’RS-232 DF1 Devices’-’Add New’. Pick the appropriate COM port and set the device to ‘micro/panelview’. Then select ‘Autoconfigure’. It should find the PLC and set the port appropriately. Click ‘OK’ and get the RSLogix software back.
5. Click ‘OK’ on the new file creation screen. The program will put up a project window. This will include a scrolling menu on the left that allows access to many functions of the PLC. The ladder logic will appear on the right hand side. At this point you are ready to enter some ladder logic.
8.1.4 Setting up a new Project and Program
1. A window will appear on the screen. On the right hand side is where ladder logic is entered and displayed. On the left are system settings. On the top are the controls used for programming and other functions.
2. Look carefully at the bar at the top of the screen. At the right hand side there are small symbols. Point to the left most symbol and hold down the left mouse button (keep it pushed for now). Drag the mouse down to the ladder logic window. A green box will appear, drag the mouse pointer to it and let the mouse button go. This should add an empty rung to the program.
5. Now the names of the inputs and outputs will be added. For the input contact, double click with the left mouse button on the “?” above the input contact. Type in the value shown below and press return. Do the same for the output coil. Note: what is displayed will appear different from what was entered.
8.1.5 Downloading and Entering a Program
2. You will be asked if you are sure you want to download, select “yes”. You may get a message that the SLC is in “RUN MODE”. If you select “Yes” the program in the PLC will stop running so that the new program can be downloaded. After the program is downloaded you will be asked if you want to switch back to “RUN” mode, select “Yes”.
3. When asked “Do you want to go Online?” select “Yes”. The screen will now show the actual state of PLC inputs and outputs. Turn on Input 0 to the PLC, and notice that the rung on the screen changes. It is also worth noticing that there is a slight delay between pushing the switch, and the change on the screen.
8.1.6 Complex Ladder Diagrams
3. Go offline and add in the branch in the figure below. To do this drag down a branch icon from the bar above to a green box before the two input contacts. Then use the mouse to drag the other side of the branch (shown as a red box) to the other side of the input contacts.
2. Download the ladder logic and observe how the switches change the operation of the latches. Notice that the second last line of ladder logic has no effect: this is because the output ‘O:0/2’ was used twice, and only the last use counts.
3. After a latch is set (O:0/1) turn off the PLC, and turn it back on. Do the latched outputs stay latched? The programming software will give an error message “Communications loss to processor“, just click “retry” to reconnect to the PLC.
8.1.10 Basic Math Functions
1. Now we will write a program that adds two numbers. If the sum is greater than 8 then an output will turn on. Enter the ladder logic and run the program. Watch the values displayed, and notice how inputs I:0/0 and I:0/1 change the values.
8.1.11 Bit Memory
3. Next, look at the values in the memory of the PLC. First look at the left-hand side of the screen. One of the sections is labeled “Data Files”, under this there is “B3: Binary”. Double click on this one to bring up a display window.
8.1.12 Timer and Control Bits
8.1.13 Status Bits and Other Memory
1. Under “Data Files” select “S2: Status” to display the status memory of the PLC. Look through and notice many of the values that are available. The values that are gray can only be written to, while the others can be set by on the screen or by a ladder logic program. Also notice that memory addresses are also provided.
2. Enter the following ladder logic. Notice that the first scan value ‘S2:1/15” has been recognized as the first pass value. Download and run the program. Turn off the PLC and repeat. Notice how the bit is only set when the PLC is turned on.
3. Go to “Database” then “Address/Symbol” and double click. This will bring up a list of labels for all of the IO points in the system, including those defined by the user, and predefined values such as status bits.
8.1.14 Integer Math
8.1.15 Comparison Functions
8.1.16 Boolean Functions
8.1.17 Shift Registers
8.1.20 Jumping and Subroutines