Watlow LogicPro - Manual (Page 164)

Chapter 10: Function Blocks LogicPro User’s Guide
148 Watlow Anafaze Doc.# 28002-00 Rev 3.00
which allows their value to change dynamically within the
program.
Figure 10.28 Real Equal To Function Block
Inputs
EN is the Real Equal To enable bit. A True condition of this
bit causes the comparison between RA and RB 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 in a Ladder
Diagrams program, the value of EN is always True. In FBD,
all inputs must be connected to a Variable.
RA is one comparison value. The range of values this Variable
can assume is from -3.4x10
38 to 3.4x10 38 . If this Variable is
assigned a value out of these ranges, unpredictable results will
occur.
RB is another comparison value. The range of values this
Variable can assume is from -3.4x10
38 to 3.4x10 38 . If this
Variable is assigned a value out of these ranges, unpredictable
results will occur.
Output
Q is the Real Equal To output bit. This bit is enabled and
passes power when the enable bit is True and the value of A is
equal to the value of B.
Real Add (RADD)
The Real Add (RADD) function block, shown in Figure 10.29
on page 149, produces the sum of two real values.
RADD calculates the sum of one value (RA) and another value
(RB) and places the result in another real Variable (RC), when
the enable bit (EN) is True. The values of RA and RB can be
preset to a constant or assigned a Variable name, which allows
their value to change dynamically within the program.