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Appendix D How to Use PLC Function|
Revision June 2008, 04EE, SW--PW V1.11/CTL V2.11 D-53
API Mnemonic Operands Function
21
SUB P S
1
, S
2
,
D Subtraction
Bit Devices Word devices Program Steps Type
OP
X Y M K H KnX KnY KnM T C D
S
1
* * * * * * * *
S
2
* * * * * * * *
D * * * * *
SUB, SUBP: 7 steps
DSUB, DSUBP: 13 steps
Operands:
S1: Minuend S2: Subtrahend D: Remainder
Explanations:
1. This instruction subtracts S1 and S2 in BIN format and stores the result in D.
2. The highest bit is symbolic bit 0 (+) and 1 (-), which is suitable for algebraic subtraction.
3. Flag changes in binary subtraction
In 16-bit instruction:
A. If the operation result ＝ 0, zero flag M1020 = On.
B. If the operation result ＜ -32,768, borrow flag M1021 = On.
C. If the operation result ＞ 32,767, carry flag M1022 = On.
Program Example:
In 16-bit BIN subtraction:
When X0 = On, the content in D0 will minus the content in D10 and the remainder will be stored in
D20.
X0
SUB D0 D10 D20