Chapter 11, Problem 1P

Program Plan Intro

Math instruction:

• Math instructions refer to all output instructions that uses the data of two words or registers and perform the desired function.
• Math instructions are programmed depending on the type of processor used.
• The data manipulation instructions are almost similar to math instructions.
• Math instructions are normally used to perform arithmetic functions on the values stored in memory words or registers.

Math functions:

The basic math functions performed by PLCs are as follows:

• Addition
  • This function is used to add one piece of data to another.
  • It is also called as ADD.
• Subtraction
  • This function is used to subtract one piece of data from another.
  • It is also called as SUB.
• Multiplication
  • This function is used to multiply one piece of data by another.
  • It is also called as MUL.
• Division
  • This function is used to divide one piece of data from another.
  • It is also called as DIV.

Terms used:

The following terms are used in the instruction.

• Source A
  • Source A refers to the address of the first piece of data that is used in the instruction.
• Source B:
  • Source B refers to the address of the second piece of data that is used in the instruction.
• Destination
  • Destination refers to the address where the results of the instruction are stored.

Given:

• In the given figure, the instruction ADD is executed to add the values accumulated at “C5:0” and “C5:1” and the result will be stored at the address “N7:1”.
• The instruction GREATER THAN OR EQUAL (GEQ) is executed to activate the PL1 output.
• Here, the instruction will become true when the value accumulated at the address “N7:1” is greater than or equal to the constant value “350”.

Explanation of Solution

b.

Status of output PL1:

“No”, the output PL1 will not be energized when the accumulated value of counter “C5:0” and “C5:1” is “148” and “36” respectively.

Reason:

• The accumulated value of counter “C5:0” is “148” and the accumulated value of counter “C5:1” is “36”...

Explanation of Solution

c.

Value of the numbers stored:

Assume that the accumulated value of counter “C5:0” is “250” and the accumulated value of counter “C5:1” is “175”.

(1)

Value stored in “C5:0.ACC”:

Since, the given program stores the accumulated value of counter addressed at “C5:0”, the “C5:0.ACC” contains the value of the number “250”.

(2)

Value stored in “C5:1.ACC”:

Since, the given program stores the accumulated value of counter addressed at “C5:1”, the “C5:1.ACC”contains the value of the number “175”...

Explanation of Solution

d.

Status of output PL1:

“Yes”, the output PL1 will get energized when the accumulated value of counter “C5:0” and “C5:1” is “175” and “250” respectively.

Reason:

• The accumulated value of counter “C5:0” is “250” and the accumulated value of counter “C5:1” is “175”...