Mitsubishi Electric MELSEC-Q/L - Page 240

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6 BASIC INSTRUCTIONS
6.2 Arithmetic Operation Instructions
DB+(P), DB-(P) [When three data are set]
Processing details
■DB+
• Adds the BCD 8-digit data designated by (S1) and the BCD 8-digit data designated by (S2), and stores the result of the
addition at the device designated by (D).
• 0 to 99999999 (BCD 8 digits) can be assigned to (S1), (S2) and (D).
• If the result of the addition operation exceeds 99999999, the upper bits will be ignored. The carry flag (SM700) in this case
does not turn ON.
■DB-
• Subtracts the BCD 8-digit data designated by (S1) and the BCD 8-digit data designated by (S2), and stores the result of the
subtraction at the device designated by (D).
• 0 to 99999999 (BCD 8 digits) can be assigned to (S1), (S2) and (D).
• The following will result if an underflow is generated by the subtraction operation: The carry flag (SM700) in this case does
not turn ON.
(S1): Data to be added to/subtracted from or head number of the devices where the data to be added to/subtracted from is stored (BCD 8 digits)
(S2): Data for adding/subtracting or head number of the devices where the data for adding/subtracting is stored (BCD 8 digits)
(D): Head number of the devices where the addition/subtraction operation result is stored (BCD 8 digits)
Setting
data
Internal device R, ZR J\ U\G Zn Constant
K, H
Others
Bit Word Bit Word
(S1)  
(S2)  
(D)  
Command
Command
P
S1 S2
D
S1 S2
D
DB+, DB-
DB+P, DB-P
DB+/DBindicates an instruction symbol of .
+
10234
5
67
(Upper 4 digits) (Lower 4 digits)
6
5
789123
(Upper 4 digits) (Lower 4 digits)
8
5
023690
(Upper 4 digits) (Lower 4 digits)
+1+1 +1
Digits exceeding the designated number
of digits are assumed to be 0.
S1 S1 S2
D D
S2
10654 32199 000000 00654 321
10234 567
(Upper 4 digits) (Lower 4 digits)
65789123
(Upper 4 digits) (Lower 4 digits)
5 4 6
(Upper 4 digits) (Lower 4 digits)
+1+1 +1
Digits exceeding the designated
number of digits are assumed to be 0.
S1 S1 S2
D D
S2
555 55
2134 56792134 5678 99 999999