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

Arithmetic Status Flags:
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
Example 1:
Compute/Math Instructions (CPT, ADD, SUB, MUL, DIV, MOD, SQR, SQRT, NEG, ABS)
To detect a possible divide-by-zero, examine the minor fault bit (S:MINOR). See
Logix5000 Controllers Common Procedures Programming Manual, publication
1756-PM001.
Arithmetic status flags are affected.
A minor fault occurs if
The divisor is zero
Execution:

Relay Ladder

Action
The rung-condition-out is set to false.
The rung-condition-out is set to false.
Destination = Source A / Source B
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.
Divide float_value_1 by float_value_2 and place the result in divide_result.
Relay Ladder
Rockwell Automation Publication 1756-RM003N-EN-P - October 2011
Fault type
4
Chapter 6
Fault code
4
277