F
3-
-0
4D
A
S
4
C
h.
Is
ol
at
ed
A
na
lo
g
O
ut
.
8--12
F3--04DAS 4-Channel Isolated Analog Output
The remaining twelve bits represent the
analog data in binary format.
Bit
Value
Bit
Value
0 (LSB)
1
6
64
1
2
7
128
2
4
8
256
3
8
9
512
4
16
10
1024
5
32
11
2048
1
1
7
R001
MSB
LSB
0
1
0
1
1
6
1
1
5
1
1
4
1
1
3
1
1
2
1
1
1
1
1
0
0
1
7
0
1
6
0
1
5
0
1
4
0
1
3
0
1
2
0
1
1
-- data bits
R011
Since the module has 12-bit resolution, the analog signal is converted into 4096
“pieces” ranging from 0 -- 4095 (2
12
). For example, with a 0 to 10V scale, a 0V signal
would be 0, and a 10V signal would be 4095. This is equivalent to a a binary value of
0000 0000 0000 to 1111 1111 1111, or 000 to FFF hexadecimal. The following
diagram shows how this relates to each signal range.
+V
0V
--V
0
4095
--10V -- +10V
--5V -- +5V
+V
0V
0
4095
0V -- 10V
0V -- 5V
+5V
1V
0
4095
1V -- 5V
20mA
4mA
0
4095
4 -- 20mA
Each “piece” can also be expressed in
terms of the signal level by using the
equation shown. The following table
shows the smallest signal levels that will
possibly result in a change in the data
value for each signal range.
Resolution
=
H
-
L
4095
H = high limit of the signal range
L = low limit of the signal range
Range
Highest Signal
Lowest Signal
Smallest Change
--10 to +10V
+10V
--10V
4.88 mV
--5 to +5V
+5 V
--5V
2.44 mV
0 to 5V
5V
0V
1.22 mV
0 to 10V
10V
0V
2.44 mV
1 to 5V
5V
1V
0.98 mV
4 to 20mA
20mA
4mA
3.91
µ
A
Now that you understand how the module and CPU work together to gather and
store the information, you’re ready to write the control program.
Analog Data Bits