Exercise 1: Ladder Logic Programming
The finished result of this exercise will be this ladder running in the ELC:
•
Click the icon that represents a normally
open contact in the Ladder Diagram
Toolbar (far left). The window to the
right will appear with the type of contact
you selected at the top.
•
Select “M” from the Device Name pull
down list. Note that the description of
this type of reference changes to
“Internal Relay.”
•
Leave the second window set for 0 and
click “OK”. A N.O. contact with the
reference “M0” will appear in the
window.
•
Create a normally closed contact that
references “M1” in the next available
“cell”.
•
While the next cell is highlighted, press the F7 key on your keyboard. The device input window will appear
with “Output coil” as the type of contact. Make this object reference “Y0”. Y0 is the first digital output on the
processor.
•
With the first cell of line 2 highlighted, type LD Y0 on your keyboard. Case is not sensitive. The Input
instruction window will appear. “LD” is the command code for a normally open contact. (To see a list of those
codes, select HELP>ELC INSTRUCTION AND SPECIAL REGISTERS REFERENCE.) “Y0” is the bit that
we want to reference. Either click “OK” on that window or just press the enter key. The window will close and
the contact will appear in the cell that was highlighted.
•
When drawing vertical lines to connect rungs, the line draws from the lower left corner of the selected cell
down to the rung below, so you will need to highlight the cell with the normally closed contact that references
M1 and then either press F9 on your keyboard or click the vertical line tool on the toolbar.
•
Highlight the first cell in the third line of the diagram and type the word end and press enter. Choose
COMPILER>LADDER => INSTRUCTION to compile the project. This will complete your first simple latching
circuit program.
•
To download the program to the ELC, choose COMMUNICATION>TRANSFER SETUP. Be sure that the
Selected Operation is “Write to ELC” and that Whole Range is selected in the range setup section. Click
“Execute” and the program will be sent to the processor.
Pub. No. TR05003001E
For more information visit:
www.EatonElectrical.com
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