Delta AH500 - Page 645

Chapter 6 Applied Instructions
6-477
API Instruction code Operand
Function
2112 $LEFT P
S, n, D
The retrieve of the characters in the
string begins from the left.
Device
X Y M S T C HC D L SM SR E PR K 16# “$” DF
S
        
n
          
D
      
Pulse instruction
16-bit instruction (7-13 steps)
32-bit instruction
AH500
AH500
-
Symbol:
S
：
String Word
n
：
Number of characters which are
retrieved
Word
D
：
Device in which the characters
retrieved are stored
Word
Explanation:
1. The instruction is used to retrieve n characters in the string in S from the left, and the
characters which are retrieved are stored in D.
2. If n is 0, the value in D is 0.
b15
b0
b7
b8
16#00
S
+1
S
.....................
~
~
D
+1
D
...........
b15
b0
b7 b8
~
First ASCII code
Second ASCII code
Third ASCII code
Fourth ASCII code
First ASCII code
Second ASCII code
Third ASCII code
Fourth ASCII code
Last ASCII code
n ASCII code from the last
th
n-2 ASCII code from the last
th
n-1 ASCII code from the last
th
n+1 ASCII code from the last
th
n ASCII code from the last
th
n-2 ASCII code from the last
th
n-1 ASCII code from the last
th
16#00
If the data in S is ABCDEF12345 and n is 7, seven characters in the string in S are retrieved
from the left. The conversion result is as follows.
b15
b0
b7 b8
0016#
S
+1
S
+2
S
+3
S
16#41(A) 16#42(B)
43(C)16# 44(D)16#
46(F)16#
45(E)16#
31(1)16#
32(2)16#
34(4)16#
33(3)16#
+4
S
+5 S
35(5)16#
b15
b0
b7 b8
D
+1
D
+2
D
16#41(A) 42(B)16#
43(C)16# 44(D)16#
46(F)16#
45(E)16#
Seventh character
ABCDEF12345
+3
D
31(1)16#
0016#
Example:
When M0 is ON, the instruction $LEFT is executed. The six characters starting from the character in
D100 are retrieved, and stored in D10~D12.