Function Block; Fbd_Compare Structure - Allen-Bradley Logix5000 Reference Manual

Chapter 5 Compare Instructions (CMP, EQU, GEQ, GRT, LEQ, LES, LIM, MEQ, NEQ)
Input Parameter Data Type
EnableIn BOOL
SourceA REAL
SourceB REAL
Output Parameter Data Type
EnableOut BOOL
Dest BOOL
Description:
Arithmetic Status Flags:
Fault Conditions:
258

Function Block

Operand Type
NEQ tag FBD_COMPARE

FBD_COMPARE Structure

Description
Enable input. If cleared, the instruction does not execute and outputs are not updated.
Default is set.
Value to test against SourceB.
Valid = any float
Value to test against SourceA.
Valid = any float
Description
The instruction produced a valid result.
Result of the instruction. This is equivalent to rung-condition-out for the relay ladder
NEQ instruction.
The NEQ instruction tests whether Source A is not equal to Source B.
When you compare strings:
· strings are not equal if any of their characters do not match.
· ASCII characters are case sensitive. Upper case 'A' ($41) is not equal to
lower case 'a' ($61).
L
e
ss
er
Not affected
None
Rockwell Automation Publication 1756-RM003N-EN-P - October 2011
Format
Structure
ASCII Characters
1ab
1b
G
re
A
at
er
AB
B
a
ab
Description
NEQ structure
Hex Codes
$31$61$62
$31$62
$41
$41$42
AB < B
$42
a > B
$61
$61$62