Publication 1763-RM001C-EN-P - October 2009
Compare Instructions
183
The MEQ instruction is used to compare whether one value (source) is
equal to a second value (compare) through a mask. The source and the
compare are logically ANDed with the mask. Then, these results are
compared to each other. If the resulting values are equal, the rung state is
true. If the resulting values are not equal, the rung state is false.
For example:
The source, mask, and compare values must all be of the same data size
(either word or long word). The data ranges for mask and compare are:
•
-32,768 to 32,767 (word)
•
-2,147,483,648 to 2,147,483,647 (long word)
The mask is displayed as a hexadecimal unsigned value from 0000 to
FFFF FFFF.
Addressing Modes and File Types can be used as shown in the following
table:
Source:
Compare:
1 1 1 1 1 0 1 0 0 0 0 0 1 1 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0
Mask:
Mask:
1 1 0 0 1 1 1 1 1 1 0 0 0 0 1 1 1 1 0 0 1 1 1 1 1 1 0 0 0 0 1 1
Intermediate Result:
Intermediate Result:
1 1 0 0 1 0 1 0 0 0 0 0 0 0 0 0 1 1 0 0 1 1 1 1 0 0 0 0 0 0 0 0
Comparison of the Intermediate Results: not equal
MEQ Instruction Valid Addressing Modes and File Types
For definitions of the terms used in this table see Using the Instruction Descriptions on page 82.
Parameter
Data Files
Function Files
(1)
CS
-
Comms
IO
S -
I
/O
DL
S
-
D
a
ta
L
o
g
Address
Mode
(2)
Address Level
O
I
S
B
T,
C
, R
N
F
ST
L
MG,
PD
RI/
R
IX
PL
S
RTC
HS
C
PTO, PWM
STI
EII
BH
I
MMI
LC
D
Imme
diate
Di
re
c
t
Indir
e
c
t
Bi
t
Wo
rd
Lo
ng
W
o
rd
Elemen
t
Source
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Mask
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Compare
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
(1) PTO and PWM files are only for use with MicroLogix 1100 BBB unit.
(2) See Important note about indirect addressing.
IMPORTANT
You cannot use indirect addressing with: S, ST, MG, PD,
RTC, HSC, PTO, PWM, STI, EII, BHI, MMI, CS, IOS, and
DLS files.
efesotomasyon.com - Allen Bradley,Rockwell,plc,servo,drive