F
3--
08
A
D
8-
C
ha
nn
el
A
na
lo
g
In
pu
t
4--9
F3--08AD 8-Channel Analog Input
Writing the Control Program
Since all channels are multiplexed into a single data word, the control program must
be setup to determine which channel is being read. Since the module provides input
points to the CPU, it is very easy to use the active channel status bits to determine
which channel is being monitored.
1
1
0
F3--08AD
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)
8ch
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
The following example shows a program that is designed to read a single channel of
analog data into a Register location on every scan. Once the data is in a Register,
you can perform math on the data, compare the data against preset values, etc. This
example is designed to read channel 1. Since you use jumpers to select the number
of channels to scan, this is the only channel that you can use in this manner.
374
DSTR1
R001
F51
Read the data
This rung loads the data into the accumulator on
every scan. (You can use any permissive contact.)
BCD
F86
DOUT
R400
F60
Since the active channel indicators are all off when
channel 1 is being read, you would not have to use
them. (Since you cannot isolate the individual
channels for scanning, channel 1 is the only
channel that can be used in this manner.) The
DOUT instruction moves the data to a storage
register. The BCD value will be stored in R400 and
R401. (Two bytes are required for four digit BCD
numbers.)
The DL305 CPUs perform math operations in
BCD. This instruction converts the binary data to
BCD. (You can omit this step if your application
does not require the conversion.)
Identifying the
Data Locations
Single Channel on
Every Scan