Relay Ladder; Function Block; Structured Text - Allen-Bradley Logix5000 Reference Manual

Fault Conditions:
Condition
Prescan
Rung-condition-in is false
Rung-condition-in is true
Postscan
Condition:
Prescan
Instruction first scan
Instruction first run
EnableIn is cleared
EnableIn is set
Postscan
Trigonometric Instructions (SIN, COS, TAN, ASN, ASIN, ACS, ACOS, ATN, ATAN)
None
Execution:

Relay Ladder

Action
The rung-condition-out is set to false.
The rung-condition-out is set to false.
The controller calculates the arc cosine of the Source and places the result in the Destination.
The rung-condition-out is set to true.
The rung-condition-out is set to false.

Function Block

Action
No action taken.
No action taken.
No action taken.
EnableOut is cleared.
The instruction executes.
EnableOut is set.
No action taken.
Example:
Calculate the arc cosine of value and place the result in result.
Relay Ladder

Structured Text

result := ACOS(value);
Function Block
Rockwell Automation Publication 1756-RM003N-EN-P - October 2011
Chapter 14
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