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A n a l o g I n p u t
C h a n n e l # n
R B n
O P E N
The RC network can also be used as current sensor, which transfers the
current into voltage. To get the ground reference level, user can cut-off RA
and let RB = 0 Ohm, thus grounding the input signal. The users can use
the ground input to calibrate the offset voltage by software.
Signal Channel Control
There are two ways to control the channel number. The first one is the
software programming and the second one is the auto channel
scanning which is controlled by the ASCAN bit in AD trigger mode control
register. As ASCAN is cleared (0), the value of AD channel Control
register defines the channel to be selected.
As ASCAN is set 1, the value in AD channel control register defines the
ending channel number of auto -scanning operation. Under auto scan
mode, the channel is scanning from channel 0 to the ending channel.
Whenever a trigger signal is rising, the channel number to be selected
will increase automatically. For example, if the ending channel number
is 3, the auto channel scanning sequence is 0,1,2,3,0,1,2,3, ... , until the
ASCAN bit is cleared.
Signal Range
The proper signal range is important for data acquisition. The input
signal may be saturated if the A/D gain is too large. Sometimes, the
resolution may be not enough if the signal is small. The maximum
signal range of PCI-9113A is 10 volts when the A/D gain value is 1.
The A/D gain control register controls the maximum signal input
range.
The
signal
(1,10,100,1000*). The signal range of the 32 channels will be
identical all the time even if the ch
available signal polarity on PCI-9113A are bi-polar and uni-polar
configuration.
R A n
To Multiplexer
0 . O h m
C A n
O P E N
gain
is
programmable
nnel number is scanning. The
a
Operation Theorem 25
A/D
with
4
levels
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