Mitsubishi Electronics 13JW55 ユーザーズマニュアル

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7.5.2  A/D conversion characteristics 
(1)  A/D conversion characteristics on voltage inputs 
(For analog input range from -10 to 10V in a standard resolution mode) 
 
2000
2001
2002
2003
2004
Dig
ita
l outp
u
t
5.
0
00
0
V
5.
0
02
5
V
Input voltage
2.5mV
10V
0
-10V
-4000
0
4000
D
igi
ta
l ou
tp
ut
 va
lu
e
Analog input voltage
Figure 7.12    A/D conversion characteristics (voltage input) 
 
A/D converter modules convert analog values input from other devices to digital 
quantities so that CPUs can operate those values. On voltage inputs, for 
example, A/D converter modules convert -10V to a quantity of -4000 and 10V to 
4000. This means that the modules convert an input voltage of 2.5mV to a 
digital quantity of 1, and abandon values smaller than 2.5mV. 
 
(2)  A/D conversion characteristics on current inputs 
(For analog input range from 0 to 20mA in a standard resolution mode) 
 
Dig
ita
l outp
u
t
1
0
.000m
A
1
0
.005m
A
Input current
5   A
20mA
0
-20mA
-4000
0
4000
Digita
l o
u
tpu
t value
Analog input current
2000
2001
2002
2003
2004
2005
Figure 7.13    A/D conversion characteristics (current input) 
 
The modules convert current an input of 0mA to 0 for an output, and 20mA to 
4000. This means that the modules convert an input current of 5
μA to a digital 
quantity of 1, and abandon values smaller than 5
μA. 
 
REMARK 
 
A voltage or current value that is equivalent to a digital value of 1 through A/D 
conversion (maximum resolution) differs depending on the setting of the 
resolution mode (1/4000, 1/12000, 1/16000) or the output range.