Mitsubishi MELSEC Q Series, Programming Manual

Page: 198 / 816

6-36
6.2 Arithmetic Operation Instructions
6.2.6 8-digit BCD data addition and subtraction
DB+, DB-
DB-(P)
(1) Subtracts the 8-digit BCD data specified for and the 8-digit BCD data specified for ,
and stores the result of the subtraction to the variable specified for .
(2) Values can be specified between 0 and 99999999 (8-digit BCD) for , and .
(3) The following is the result when an underflow is generated by the subtraction operation.
The carry flag in this case does not turn ON.
O p erat i on E rror
In the following case, an operation error occurs, the error flag (SM0) is turned ON, and the
corresponding error code is stored
to SD0.
• The , , or BCD value is outside the range of 0 to 99999999. (Error code: 4100)
Program E xam pl e
(1) In the following program, the BCD value in Var_D3 is added to the BCD value in Var_ Z
when X20 turns ON, and the result is stored to Var_R10.
[Structured ladder]
(2) In the following program, the BCD data in Var_Z is subtracted from the BCD data in Var_D3
when X20 turns ON, and the result is stored to Var_R10.
[Structured ladder]
s 1 s 2
d
−
1 0 2 3 4 5 6 7 6 5 7 8 9 1 2 3 5 4 6 5 5 5 5 5
s 1 s 2 d
( Upp er 4 d i g i ts) ( L o w er 4 d i g i ts) ( Upp er 4 d i g i ts) ( L o w er 4 d i g i ts) ( Upp er 4 d i g i ts) ( L o w er 4 d i g i ts)
D i g i ts exceed i ng t h e s p ec ifi ed num b er
o f d i g i ts are assumed to b e 0 .
s 1 s 2 d
2 1 3 4 5 6 7 9 2 1 3 4 5 6 7 8 9 9 9 9 9 9 9 9
s 1 s 2 d