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FX Series Programmable Controlers Applied Instructions 5
5-50
Points to Note:
a) When floatin
g
point numbers are used the zero, borrow and carr
y
fla
g
s (M8020, M8021 and
M8022 respectivel
y
) operate at the followin
g
times; M8020, Zero: is activated when the
result is Zero.
M8021, Borrow: is activated when the result is smaller than the smallest possible number.
The result is forced to equal the smallest number and the associated fla
g
is set ON.
M8022, Carr
y
: is activated when the result is lar
g
er than the lar
g
est possible number. The
result is forced to equal the lar
g
est number and the associated fla
g
is set ON.
b) Floatin
g
point numbers alwa
y
s
occup
y
32 consecutive bits, i.e. 2
consecutive data re
g
isters. When
convertin
g
between float and
decimal numbers please al-low
enou
g
h destination devices, i.e.
Instruction
Double word
operation
Status of
M8023
Number of
source
registers (S)
Number of
destination
registers (D)
Remark
FLT
NO
OFF 1 (S)
2 (D, D
+1
)
Convert to floatin
g
point
FLT (INT) ON
2 (S, S
+1
)
1 (D) Convert to decimal
DFLT
YES
OFF
2 (S, S
+1
) 2 (D, D
+1
)
Convert to floatin
g
point
DFLT
(DINT)
ON
2 (S, S
+1
) 2 (D, D
+1
)
Convert to decimal
Zero M8020
Infinit
y
Positive Value
Borrow
M8021
Carr
y
M8022
Ne
g
ative Value
Ver
y
small
Carr
y
M8022
Infinit
y
General note:
For more information about float and scientific notations please see Chapter 4, Advanced
Devices, pa
g
e 4-46