Watlow LogicPro - Manual (Page 143)

LogicPro User’s Guide Chapter 10: Function Blocks
Doc.# 28002-00 Rev 3.00 Watlow Anafaze 127
Inputs
EN is the Greater Than enable bit. A True condition of this bit
causes the comparison between A and B to occur. In a program
using Ladder logic, the value of EN is determined by the
Boolean evaluation of elements placed between the left power
rail and EN in the function block. In FBD programs, the value
of EN is determined by the Variable connected to EN. If no
contacts are placed on the rung before EN, the value of EN is
always True.
A is one comparison value. In Ladder logic, assign this input a
symbolic name or constant value in the
Assign Function
Block Symbolic Input/Output dialog box. In FBD, assign
a variable to this input in the Variable Assignment dialog
box. The range of values this Variable can assume is from -
32,768 to 32,767, including 0 for INT type Variables and -
2,147,483,648 to 2,147,483,647, including 0 for LONG type
Variables. If this Variable is assigned a value out of these
ranges, unpredictable results will occur.
B is another comparison value. In Ladder logic, assign this
input a symbolic name or constant value in the
Assign
Function Block Symbolic Input/Output dialog box. In
FBD, assign a variable to this input in the Variable
Assignment dialog box. The range of values this Variable
can assume is from -32,768 to 32,767, including 0 for INT type
Variables and -2,147,483,648 to 2,147,483,647, including 0
for LONG type Variables. If this Variable is assigned a value
out of these ranges, unpredictable results will occur.
Output
Q is the Greater Than output bit. This bit is enabled and passes
power when the enable bit is True and the value of A is greater
than the value of B.
Less Than (LT)
The Less Than function block, shown in Figure 10.12 on page
128, tests if a value is less than a reference value.
LT tests whether one value (A) is less than another value (B)
when the enable bit (EN) is True. If the relationship ATrue, then the output bit (Q) is enabled. The output bit is
disabled either when the enable bit becomes False or the value
of A is no longer less than B. The values of A and B can be
preset to a constant or assigned a symbolic name, which
allows their value to change dynamically within the program.