Mitsubishi Electric FX3G SERIES Programming Manual page 277

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
Program example
1. Difference between the SUB instruction and the DEC instruction used by a program for
subtracting "1"
When SUB[P] is executed, "1" is subtracted from the contents of D0 every time X001 turns from OFF to ON.
SUB[P] instruction is similar to DECP instruction described later except the contents shown in the table below:
Flag (zero, borrow or carry)
S
16-bit
operation
S
S
32-bit
operation
S
X001
FNC 21
SUBP
X001
FNC 25
DECP
[D] SUB [P] instruction
Operates
←−2←−1←0←−32768
−(+1)=
D
+32767→0→+1→+2→
−(−1)=
D
←−2←−1←0←−2,147,483,648
−(+1)= D
+2,147,483,647→0→+1→+2→
−(−1)= D
S S D
1 2
D 0 K 1 D 0
D 0
10 Arithmetic and Logical Operation (+, −, ×, ÷) – FNC 20 to FNC 29
[D] DEC [P] instruction
−32,768→+32,767→+32,766
−2,147,483,648→+2,147,483,647→+2,147,483,646
(D 0) − 1→(D 0)
(D 0) − 1→(D 0)
10.2 FNC 21 – SUB / Subtraction
Does not operate
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