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Goodheart-Willcox Co., Inc. Objectives Program the add instruction
in the PLC ladder logic diagram. Program the subtract instruction
in the PLC ladder logic diagram. Program the multiply instruction
in the PLC ladder logic diagram. Program the divide instruction in
the PLC ladder logic diagram.
Slide 4
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Goodheart-Willcox Co., Inc. Addition Add (ADD) instruction has
three operands:Add (ADD) instruction Two operands hold source data
(Source A and Source B), which are added together. Either both
sources can be registers or one source can be a register while the
other one is a number. Third operand is the destination.
Slide 5
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Goodheart-Willcox Co., Inc. Addition (Cont.) Add instruction for
Allen-Bradley SLC 500 series PLC displayed in block format.
Slide 6
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Goodheart-Willcox Co., Inc. Description of Status Bits
Slide 7
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Goodheart-Willcox Co., Inc. Subtraction Subtract (SUB) instruction
has three operands:Subtract (SUB) instruction Two operands, Source
A and Source B, hold the source data. Content of Source B is
subtracted from Source A. Result is placed in the destination.
Slide 8
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Goodheart-Willcox Co., Inc. Subtraction (Cont.) Subtract
instruction for the Allen-Bradley SLC 500 series PLC displayed in
block format.
Slide 9
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Goodheart-Willcox Co., Inc. Multiplication Multiply (MUL)
instruction has three operands:Multiply (MUL) instruction Two
operands hold the source data (Source A and Source B). Either both
sources can be registers, or one source can be a register while the
other one is a number. Destination must be a register.
Slide 10
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Goodheart-Willcox Co., Inc. Multiplication (Cont.) Multiply
instructions in SLC 500 series PLCs displayed in block format.
Slide 11
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Goodheart-Willcox Co., Inc. Division Divide (DIV) instruction has
three registers:Divide (DIV) instruction Two registers hold the
source data (Source A and Source B). Either both sources can be
registers or one source can be a register while the other one is a
number. Destination must be a register.
Slide 12
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Goodheart-Willcox Co., Inc. Division (Cont.) Divide instructions in
SLC 500 series PLCs displayed in block format.
Slide 13
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Goodheart-Willcox Co., Inc. Advanced Math Instructions Advanced
math instructions are used to perform mathematical
computations.
Slide 14
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Goodheart-Willcox Co., Inc. Advanced Math Instructions (Cont.)
Compute (CPT) instruction may be used to solve mathematical
equations.
Slide 15
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Goodheart-Willcox Co., Inc. Advanced Math Instructions Example
Given the following equation, you can use the CPT instruction to
solve it. Y = (A (ln B) e C ) + (tan D)
Slide 16
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Goodheart-Willcox Co., Inc. Advanced Math Instructions Example
(Cont.) First assign floating point register locations for the
parameters in the equation. Note that integer registers such as
N7:0 hold integer numbers. Floating point registers such as F8:0
hold a real number that has both integer and fractional part.
Slide 17
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Goodheart-Willcox Co., Inc. Advanced Math Instructions Example
(Cont.) Assigned registers are: A = F8:0 B = F8:1 C = F8:2 D = F8:3
Y = F8:4
Slide 18
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Goodheart-Willcox Co., Inc. Advanced Math Instructions Example
(Cont.) Normally open contact I:1/0 is closed, equation in CPT
instruction block calculated. Result is placed in floating point
register four (F8:4).
Slide 19
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Goodheart-Willcox Co., Inc. PLC Ladder Logic Diagram
Slide 20
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Goodheart-Willcox Co., Inc. Commonly Used Math Instructions
Slide 21
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Goodheart-Willcox Co., Inc. Glossary Add (ADD) instruction -
Instruction that calculates the sum of Source A and Source B.
Divide (DIV) instruction - Instruction that calculates the quotient
that results from dividing Source A by Source B.
Slide 22
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Goodheart-Willcox Co., Inc. Glossary Multiply (MUL) instruction -
Instruction that calculates the product of Source A and Source B.
Subtract (SUB) instruction - Instruction that calculates the
difference between Source A and Source B.