Two Contacts in Series (Logical AND)
The first ladder program to be implemented will be a simple series control rung. Two switches, SW3 and SW4, will be placed in series and will be used to control a single light, LA1.
Use the right mouse button to access editing functions whenever possible. Clicking on the right mouse button brings up the editing menu with available options. The menu is different depending on the (box) cursor location. If the box is on the left rail of a rung, rung editing functions: accept, cancel, cut, paste, append rung, insert rung, etc. If the box is on an instruction, then instruction editing functions are presented if the right mouse button is clicked: append/insert instruction, insert/append branches, change instruction type, cut, paste, etc. As you place the instructions into a ladder program, one can either append or insert the instruction. Append places the new instruction to the right of the current cursor position, and insert places the instruction to the left. If the cursor is on the left power rail, append or insert will append or insert a rung. Appended rungs are placed below the current rung, and inserted rungs are placed abovethe current rung.
If ladder window is not displayed, double-click on “MainRoutine” under “Main Task” in the project window. Place the cursor (blue box) on the END rung. If not, click on the left rail of the bottom rung.
Click on the Insert Rung icon (├─┤). A new rung appears at the top of the screen with a blue box on the left. The "e" in the box indicates this is an edit zone. Now the individual instructions for the new rung will be entered.
A normally open (NO) relay contact is needed at the input, so click on the appropriate contact symbol (┤├) above the ladder window.
Move the cursor arrow tip close to the left side of the rung and click the mouse. The NO contact will appear with a box around it and a question mark above it.
Switch SW3 will be used first, so type the tag for that switch ("SW3") and press <Enter>. The symbolic and physical address of the relay that controls the contact will appear above the contact symbol on the ladder diagram.
Click on the ┤├ contact symbol above the ladder window and then click on the new rung to the right of the first contact and add a second NO relay in series with the first. Use the symbol or address for switch SW4 ("SW4") for this contact.
The output for this rung will be light LA1.
Click on the output coil symbol (-( )-) above the ladder window.
Move the cursor to the right side of the rung and click the mouse. A normal output coil symbol will appear with a box above it.
Type the symbol or address for light LA1 ("LA1").
Since the output instruction has been entered, the rung edits may now be accepted.
Click on the left rail of the rung. A blue box appears.
Click the right mouse button.
Click on Accept Rung Edits. Now the rung is loaded into the controller's memory. The "e" indications on the left side of the rung should disappear.
To change the processor to the run mode use the following keystrokes:
Click on the arrow to the right of "REMOTE PROG" box
Click on Run
Click on Yes
The controller is now set to respond to input conditions and perform appropriate output commands. The ladder power rails change to green, indicating the processor in the run mode.
Try the input switches in various combinations and observe the output. Also observe the changing status of ladder components on the screen. Energized or true conditions cause the elements to be highlighted on the ladder diagram.
Use the right mouse button to access editing functions whenever possible. Clicking on the right mouse button brings up the editing menu with available options. The menu is different depending on the (box) cursor location. If the box is on the left rail of a rung, rung editing functions: accept, cancel, cut, paste, append rung, insert rung, etc. If the box is on an instruction, then instruction editing functions are presented if the right mouse button is clicked: append/insert instruction, insert/append branches, change instruction type, cut, paste, etc. As you place the instructions into a ladder program, one can either append or insert the instruction. Append places the new instruction to the right of the current cursor position, and insert places the instruction to the left. If the cursor is on the left power rail, append or insert will append or insert a rung. Appended rungs are placed below the current rung, and inserted rungs are placed abovethe current rung.
If ladder window is not displayed, double-click on “MainRoutine” under “Main Task” in the project window. Place the cursor (blue box) on the END rung. If not, click on the left rail of the bottom rung.
Click on the Insert Rung icon (├─┤). A new rung appears at the top of the screen with a blue box on the left. The "e" in the box indicates this is an edit zone. Now the individual instructions for the new rung will be entered.
A normally open (NO) relay contact is needed at the input, so click on the appropriate contact symbol (┤├) above the ladder window.
Move the cursor arrow tip close to the left side of the rung and click the mouse. The NO contact will appear with a box around it and a question mark above it.
Switch SW3 will be used first, so type the tag for that switch ("SW3") and press <Enter>. The symbolic and physical address of the relay that controls the contact will appear above the contact symbol on the ladder diagram.
Click on the ┤├ contact symbol above the ladder window and then click on the new rung to the right of the first contact and add a second NO relay in series with the first. Use the symbol or address for switch SW4 ("SW4") for this contact.
The output for this rung will be light LA1.
Click on the output coil symbol (-( )-) above the ladder window.
Move the cursor to the right side of the rung and click the mouse. A normal output coil symbol will appear with a box above it.
Type the symbol or address for light LA1 ("LA1").
Since the output instruction has been entered, the rung edits may now be accepted.
Click on the left rail of the rung. A blue box appears.
Click the right mouse button.
Click on Accept Rung Edits. Now the rung is loaded into the controller's memory. The "e" indications on the left side of the rung should disappear.
To change the processor to the run mode use the following keystrokes:
Click on the arrow to the right of "REMOTE PROG" box
Click on Run
Click on Yes
The controller is now set to respond to input conditions and perform appropriate output commands. The ladder power rails change to green, indicating the processor in the run mode.
Try the input switches in various combinations and observe the output. Also observe the changing status of ladder components on the screen. Energized or true conditions cause the elements to be highlighted on the ladder diagram.
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