D
3-
-0
4A
D
4-
C
ha
nn
el
A
na
lo
g
In
pu
t
2--8
D3--04AD 4-Channel Analog Input
You may recall the D3--04AD module appears to the CPU as a 16-point module.
Some of the points are inputs to the CPU and some are outputs to the module. These
16 points provide:
S
an indication of which channel is active.
S
the digital representation of the analog signal.
Since all I/O points are automatically mapped into Register (R) memory, it is very
easy to determine the location of the data word that will be assigned to the module.
1
1
0
D3--04AD
R 011
MSB
LSB
R 001
MSB
LSB
0
1
0
R 002, R012
R 000, R010
1
1
7
8pt
Relay
8pt
Output
16pt
Input
16pt
(Analog)
4ch.
Input
8pt
Output
050
--
057
040
--
047
030
--
037
020
027
--
120
127
000
007
--
100
107
010
017
--
110
117
0
1
7
-- not used
Within these two register locations, the individual bits represent specific information
about the analog signal.
The most significant point (MSP)
assigned to the module acts as an output
to the module and controls the channel
scanning
sequence.
This
allows
flexibility in your control program.
If this output is on, all channels will be
scanned sequentially. If the output is off,
you can use other points to select a
single channel for scanning.
Scan
Out 117
Channel Input
N
Off
None
N+1
On
1
N+2
On
2
N+3
On
3
N+4
On
4
N+5
On
1
N+6
Off
None
N+7
Off
None
R011
MSB
LSB
1
1
0
1
1
7
1
1
6
1
1
5
1
1
4
1
1
3
1
1
2
1
1
1
-- scan all channels
Understanding the
I/O Assignments
All Channel
Scan Output