Character String Data Comparisons - Mitsubishi Electric MELSEC-Q/L Programming Manual

Character string data comparisons

LD$, AND$, OR$
Basic
High
Process
performance
LD
AND
OR
(S1), (S2): Data for comparison or head number of the devices where the data for comparison is stored (character string)
Setting Internal device
data
Bit

(S1)

(S2)
Processing details
• Compares the character string data designated by (S1) with the character string data designated by (S2) as a normally-
open contact.
• A comparison operation involves the character-by-character comparison of the ASCII code of the first character in the
character string.
• The character string data of (S1) and (S2) for comparison refers to the data stored within the range from the specified
device number to the device number where the NULL code "00H" is stored.
• If all character strings match, the comparison result will be matched.
b15 b8 b7
(S1)
42H (B) 41H
(S1)+1
44H (D) 43H
(S1)+2 00H 45H
"ABCDE"
Instruction symbol
$=
$<>
$>
• If the character strings are different, the character string with the larger character code will be the larger.
b15 b8 b7
(S1)
42H (B) 41H
(S1)+1
44H (D) 43H
(S1)+2
00H 46H
"ABCDF"
Instruction symbol
$=
$<>
$>
6 BASIC INSTRUCTIONS
196
6.1 Comparison Operation Instructions
Redundant Universal LCPU
Command
Command Command
R, ZR
Word


b0 b15
(S2)
(A)
(S2)+1
(C)
(E) (S2)+2
Comparison operation result
Continuity
Non-continuity
Non-continuity
b0 b15
(S2)
(A)
(S2)+1
(C)
(S2)+2
(F)
Comparison operation result
Non-continuity
Continuity
Continuity
indicates an instruction symbol of
S1
S1
S1
J\
Bit Word


b8 b7 b0
42H (B) 41H (A)
44H (D) 43H (C)
00H 45H (E)
"ABCDE"
Instruction symbol
$<=
$<
$>=
b8 b7 b0
42H (B) 41H (A)
44H (D) 43H (C)
00H 45H (E)
"ABCDE"
Instruction symbol
$<=
$<
$>=
$ / $ / $ / $ / $
S2
S2
S2
U\G Zn Constant
$


Comparison operation result
Continuity
Non-continuity
Continuity
Comparison operation result
Non-continuity
Non-continuity
Continuity
/ $ .
Others

