Multiply (mul), Updates to arithmetic status bits, Entering the instruction – Rockwell Automation 1761-HHP-B30 MicroLogix 1000 with Hand-Held Programmer (HHP) User Manual
Page 174: Changes to the math register
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Chapter 10
Using Math Instructions
10–8
Use the MUL instruction to multiply one value (source A) by another
(source B) and place the result in the destination.
Source A and B can either be a word address or a constant, however both
sources cannot be a constant. The destination must be a word address.
If the result is larger than +32,767 or smaller than –32,767 (16-bits), the
32-bit result is placed in the math register.
Updates to Arithmetic Status Bits
With this Bit:
The Controller:
S0/0
Carry (C)
always resets.
S0/1
Overflow (V)
sets if overflow is detected at destination; otherwise resets.
On overflow, the minor error flag is also set. The value
–32,768 or 32,767 is placed in the destination. If S2/14
(math overflow selection bit) is set, then the unsigned,
truncated overflow remains in the destination.
S0/2
Zero (Z)
sets if result is zero; otherwise resets.
S0/3
Sign (S)
sets if result is negative; otherwise resets.
Entering the Instruction
You enter the instruction from within the program monitor functional area.
P 0 0 0
M U L
S R C A
N 4
0
P 0 0 0
M U L
S R C B
6 0
P 0 0 0
M U L
D E S T
N 6
0
Changes to the Math Register
The math register contains the 32-bit signed integer result of the multiply
operation. This result is valid at overflow.
MUL
MULTIPLY
Source A
N7:4
0
Source B
60
Dest
N7:6
0
Execution Times (
µ
sec) when:
True
False
57.96
6.78
Ladder representation:
Multiply (MUL)
2
L
8
FUN
ENT
To enter the function code, press: