4 Startup Manual
Analog Input Connections
Single-ended Channel Connections
The single-ended input configuration has only one sig-
nal wire for each channel, and the measured voltage
(Vm) is the voltage of the wire as referenced against the
common ground.
Figure 1: Single-ended Channel Connections
Differential Channel Connections
The differential input channels operate with two signal
wires for each channel, and the voltage difference
between both signal wires is measured. On PCI-1742U,
when all channels are configured to differential input,
up to 8 analog channels are available.
Figure 2: Differential Connection - Ground Signalt
Figure 3: Differential Connection - Floating Signal
Analog Output Connections
The PCI-1742U provides two D/A output channels,
AO0
and
AO1
. You may use the PCI-1742U internally-
provided precision -5V (-10V) reference to generate 0
to +5 V (+10 V) D/A output range. You may also create
a D/A output range through the external reference,
AO0_REF
. The external reference input range is +/-10
V. For example, connecting with an external reference
of -7 V will generate 0 ~ +7 V D/A output.
Figure 4: Analog Output Connections
Trigger Source Connections
Internal Pacer Trigger Connection
PCI-1742U includes one 82C54 compatible program-
mable Timer/Counter chip which provides three 16-bit
counters connected to a 10 MHz clock, each designated
specifically as Counter 0, Counter 1 and Counter 2.
Counter 0 is a counter which counts events from an
input channel or outputting pulse. Counter 1 and
Counter 2 are cascaded to create a 32-bit timer for pacer
triggering. A low-to-high edge from the Counter 2 out-
put (
PACER_OUT
) will trigger an A/D conversion on
the PCI-1742U. At the same time, you can also use this
signal as a synchronous signal for other applications.
External Trigger Source Connection
In addition to pacer triggering, the PCI-1742U also
allows external triggering for A/D conversions. A low-
to-high edge coming from
EXT_TRG
will trigger an
A/D conversion on the PCI-1742U. When
DGND
is
connected to
TRG_GATE
, the external trigger function
is thereby disabled.
Signal
Connections
