Allen-Bradley MicroLogix 1400, Инструкция по эксплуатации

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Publication 1766-RM001A-EN-P - October 2008
Math Instructions 199
•
Source and Destination can be different data sizes. Sources are
evaluated at the highest precision (word or long word) of the
operands. Then the result is converted to the size of the destination.
If the signed value of the Source does not fit in the Destination, the
overflow shall be handled as follows:
– If the Math Overflow Selection Bit is clear, a saturated result is
stored in the Destination. If the Source is positive, the Destination
is +32,767 (word) or +2,147,483,647 (long word). If the result is
negative, the Destination is -32,768 (word) or -2,147,483,648 (long
word).
– If the Math Overflow Selection Bit is set, the unsigned truncated
value of the Source is stored in the Destination.
•
Sources can be constants or an address, but both sources cannot be
constants.
•
Valid constants are -32,768…32,767 (word) and
-2,147,483,648…2,147,483,647 (long word).
•
Long File Type Address, Constant and Float File Type Address
cannot be used together in Source A, Source B and Destination.
Addressing Modes and File Types can be used as shown in the following
table:
Math Instructions (ADD, SUB, MUL, DIV, NEG, CLR) Valid Addressing Modes and File Types
For definitions of the terms used in this table see Using the Instruction Descriptions on page 92.
Parameter
Data Files
Function Files
(1)
CS - C
o
mm
s
IOS - I/O DLS - Da
ta
Lo
g
(2
)
Address
Mode
(3)
Address Level
O I S B T,
C
, R
N F ST L MG, PD RI/RIX PLS RTC HSC PTO
X
, PW
MX
STI EII BH
I
MMI LCD Imme
di
ate
Dir
e
c
t
In
dir
ect
Bit Wo
rd
Long W
o
rd
E
lement
Source A • • • • • • • • • • • • • • • • • • • • • • • • • •
Source B • • • • • • • • • • • • • • • • • • • • • • • • • •
Destination • • • • • • • • • • • • • • • • • • • •
(1) PTOX and PWMX files are only for use with MicroLogix 1400 BXB or BXBA unit.
(2) The Data Log Status file can only be used for the following math instructions: ADD, SUB, MUL, DIV, NEG, and SCP.
(3) See Important note about indirect addressing.
IMPORTANT
You cannot use indirect addressing with: S, MG, PD, RTC, HSC, PTOX,
PWMX, STI, EII, BHI, MMI, CS, IOS, and DLS files.
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