Rockwell Automation Logix5000 Controllers Ladder Diagram Programming Manual - Manual (Page 12)

Chapter 1 Program ladder diagram
• Logix5000 Controllers General Instructions Reference Manual ,
publication 1756-RM003
• Logix5000 Controllers Process and Drives Instructions Reference
Manual , publication 1756-RM006
• Logix5000 Controllers Motion Instruction Set Reference Manual ,
publication 1756-RM007
Tip: I/O module data updates asynchronously to the execution of logic. If you reference an input multiple times in
your logic, the input could change state between separate references. If you need the input to have the same
state for each reference, buffer the input value and reference that buffer tag.
You can also use Input and Output program parameters which automatically buffer the data during logix
execution. See the Logix5000 Controllers Program Parameters Programming Manual , publication 1756-PM021 .
The examples in this chapter use two simple instructions to help you learn how to
write ladder diagram logic. The rules that you learn for these instructions apply to
all other instructions.
Symbol Name Mnemonic Description
Examine If Closed XIC An input instruction that looks at one bit of data.
If the bit is Then the instruction
(rung-condition-out) is
On (1) True
Off (0) False
Output Energize OTE An output instruction that controls one bit of data.
If the instructions to the left
(rung-condition-in) are
Then the instruction turns the bit
True On (1)
False Off (0)
12 Rockwell Automation Publication 1756-PM008E-EN-P - October 2014