Rockwell Automation 1772-LV Mini-PLC - 2/15 Programmable Controller (Series B) Programming and Operations - Manual (Page 55)

Fundamental Instruction Set
Chapter 5
5Ć18
Figure 5.10
Arithmetic Instructions
111
11
030
520
G
032
1014
031
514
G +
Must be true to allow arithmetic operation Result stored at this address
Overflow (bit 14) will cause
a 1 to be displayed
Add
111
14
040
100
G
042
-009
041
109
G -
Must be true to allow arithmetic operation Result stored at this address
Underflow (bit 16) will cause
negative sign to be displayed
Subtract
111
12
130
123
G
052
503
131
061
G X
Must be true to allow arithmetic operation
051
007
X
Multiply
111
13
140
050
G
067
000
141
025
G :
Must be true to allow arithmetic operation
066
002
:
Divide
NOTE: The controller performs arithmetic and data manipulation operations
with 3-digit BCD (binary coded decimal) values.
Addition
Symbol: -(+)-
Purpose: Reports the sum of two values stored in the get instruction words.
Syntax: Programmed in the output position of the ladder diagram rung. Your
sum is stored in the add instruction word address.
Function: When the sum exceeds 999, the overflow bit (bit 14) in the add
instruction word is set. When you are in the run, test, or run program mode, the
overflow condition is displayed on the industrial terminal screen as a “1”
preceding the sum.
NOTE: If an overflow value (4 digits) is used for subsequent comparisons or
other arithmetic operations, inaccurate results could occur. Your processor