Subtraction - Mitsubishi Electric MELSEC iQ-F FX5 Programming Manual

20.3

Subtraction

SUB(_E)
These functions output the difference of input values ((s1) - (s2)).
Ladder diagram, FBD/LD
[Without EN/ENO]
s1 d
s2
Setting data
■Descriptions, types, and data types
Argument Description
EN Execution condition (TRUE: Execution, FALSE: Stop)
s1(IN1), s2(IN2) Input
ENO Output status (TRUE: Normal, FALSE: Abnormal)
d(SUB(_E)) Output
Processing details
■Operation processing
• These functions subtract the INT, DINT, or REAL type data input to (s1) and (s2) ((s1)-(s2)), and output the operation result
from (d) in the same data type as (s).
Ex.
Data type is INT
(s1) (s2)
12345 - 6789
INT INT
• A value input to (s1) and (s2) is the INT, DINT, or REAL type data value.
• If an underflow and an overflow occur in the operation result, the result will be output as follows from (d).
Data type is INT
• Even if underflow or overflow occurs in the
operation result, it is not regarded as an
operation error. "SUB_E" outputs "TRUE" from
ENO.
[Example 1]
32767-(-2)=1
(7FFFH)-(0002H)=(0001H)
The most significant bit becomes 1, and the carry
flags (SM716 and SM8022) turn on.
[Example 2]
-32768-2=-1
(8000H)-(0002H)=(FFFFH)
The most significant bit becomes 0, and the borrow
flag (SM8021) turns on.
• When the operation result is 0, the zero flag (SM8020) turns on.
[With EN/ENO]
EN ENO
s1 d
s2
(d)
5556
INT
Data type is DINT
• Even if underflow or overflow occurs in the
operation result, it is not regarded as an
operation error. "SUB_E" outputs "TRUE" from
ENO.
[Example 1]
2147483647-(-2)=-2147483647
(7FFFFFFFH)-(FFFEH)=(80000001H)
The most significant bit becomes 1, and a negative
value is output.
[Example 2]
-2147483648-2=2147483646
(80000000H)-(0002H)=(7FFFFFFEH)
The most significant bit becomes 0, and a positive
value is output.
Structured text
[Without EN/ENO]
d:=SUB(s1,s2);
[With EN/ENO]
d:=SUB_E(EN,ENO,s1,s2);
Type
Input variable
Input variable
Output variable
Output variable
Data type is REAL
An operation error occurs and an undefined value
is output.
20 ARITHMETIC OPERATION FUNCTIONS
20
Data type
BOOL
ANY_NUM
BOOL
ANY_NUM
991
20.3 Subtraction