AutomationDirect DL205 - Single Channel Selected; Using Bipolar Ranges (Multiplexing)

DL205 Analog Manual, 7th Edition Rev. D
5-18
Chapter 5: F2-08AD-2, 8-Ch. Analog Voltage Input
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Single Channel Selected
The single channel program makes it easy to determine which channel has been selected.
Using Bipolar Ranges (Multiplexing)
Some additional logic is needed with bipolar ranges to determine whether the value being
returned represents a positive voltage or a negative voltage. For example, the direction of a
motor may be needed to be known. Since the DL230 only reads one channel per scan, the last
input can be used to show the sign (X37 in the examples).
The following program shows how to accomplish this. Since a negative value is always needed
to be known, these rungs should be placed before any other operations that use the data, such
as math instructions, scaling operations, and so forth. Also, if stage programming instructions
are being used, place these rungs in a stage that is always active. Please note, this logic is only
needed for each channel that is using bipolar input signals. The following example only shows
two channels but the rungs can be repeated for all eight channels if needed.
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It is usually easier to perform math operationsinBCD.
So it is besttoconvertthe datatoBCD immediately.
Youcan leave out this instruction if your application
does notrequire it.
This instruction masksthe channelidentification bits.
Without this,the values used will not be correct, so do
not forget to include it.
Loadsthe complete datawordintothe accumulator.
TheV-memorylocation depends on the I/O
configuration. SeeAppendix Afor thememorymap.
StoreChannel 1
LD
V40401
ANDD
KFFF
BCD
OUT
V2000
When themoduleis not busy, andX34 andX35 are
off, channel1dataisstoredinV2000.
X36 X34 X35
It is usually easier to perform math operationsin
BCD, so it is besttoconvert thedatatoBCD
immediately. Youcan leave out this instructionif
your application does not require it.
This instructionmasks thechannel identification
bits. Without this,the values used will not be
correct,sodo not forget to include it.
Loadsthe complete datawordintothe
accumulator. TheV-memorylocation depends
on the I/O configuration. SeeAppendixAforthe
memory map.
LoadData
LD
V40401
ANDD
KFFF
BCD
SP1
X36X34 X35
StoreChannel 1
OUT
V2000
When themoduleisnot busy, andX34, X35 and
X36are off, channel1dataisstoredinV2000.C0
is resettoindicatechannel1’s value is positive.
SET
C0
X37
RST
C0
If X37is on, then thedatavalue representsa
negative voltage.C0isset to indicate channel
1’svalue is negative.
X36X34 X35
StoreChannel 2
OUT
V2001
When themoduleisnot busy, andX34 is on and
X35 and X36are off, channel 2dataisstoredin
V2001.C1isreset to indicate channel2’s value
is positive.
SET
C1
X37
RST
C1
If X37is on, then thedatavalue representsa
negative voltage.C1isset to indicate channel
2’svalue is negative.