Mitsubishi FX3U Series Programming Manual page 252

FX /FX Series Programmable Controllers
3U 3UC
Programming Manual - Basic & Applied Instruction Edition
Related devices
1. Relationship between the flag operation and the sign (positive or negative) of a numeric
value
Device
M8020
M8021
M8022
−2, −1,
−2, −1,
Cautions
1. When using a 32-bit operation instruction (DSUB or DSUBP)
When specifying word devices, a 16-bit word device on the low-order side is specified first, and then a word
device with the subsequent serial number is automatically set for the high-order 16 bits.
For preventing number overlap, it is recommended to always specify an even number, for example.
2. When specifying a same device as the source and destination
A same device number can be specified for both the source and the destination.
In this case, note that the addition result changes in every operation cycle if a continuous operation type
instruction (SUB or DSUB) is used.
X001
FNC 21
SUB
250
Name
ON : When the operation result is 0
Zero
OFF: When the operation result is other than 0
ON : When the operation result is less than −32768 (in 16-bit operation) or
−2,147,483,648 (in 32-bit operation)
Borrow
OFF: When the operation result is not less than −32768 (in 16-bit operation) or
−2,147,483,648 (in 32-bit operation)
ON : When the operation result is more than 32767 (in 16-bit operation) or
2,147,483,647 (in 32-bit operation)
Carry
OFF: When the operation result is not more than 32767 (in 16-bit operation) or
2,147,483,647 (in 32-bit operation)
Zero flag
−32768
0,
The most
Borrow flag
significant bit of
data becomes
"1".
Zero flag
−2,147,483,648
0,
Borrow flag
D 0 K 25
10 Arithmetic and Logical Operation (+, −, ×, ÷) – FNC 20 to FNC 29
→ For the flag operations, refer to Subsection 6.5.2.
Zero flag
−1,
0, 1
The most
significant bit
of data
becomes "0".
−1,
0, 1
Zero flag
(D 0) − 25→(D 0)
D 0
10.2 FNC 21 – SUB / Subtraction
Description
Zero flag
32767, 0,
Carry flag
Zero flag
2,147,483,647, 0,
Carry flag
1, 2
1, 2