Chapter 3
Signal Connections
©
National Instruments Corporation
3-5
Rear Signal Connector Descriptions
The rear signal connector on the cabled module is the interface between the
DAQ device and all modules in the SCXI chassis.
Pin
Signal Name
Direction
Description
1, 2
AOGND
Output
Negative Module Analog Output—With software, you can configure
these pins to connect to the analog reference.
3
MCH0+
Output
Positive Module Analog Output—This pin connects to the positive
side of the differential analog input channel 0 of the DAQ device.
4
MCH0–
Output
Negative Module Analog Output—In the reset state of the module,
this pin is configured to connect to the analog reference.
19
OUTREF
Output
Negative Module Analog Output—With software, you can configure
this pin to connect to the analog reference.
24, 33
DGND
—
Digital Ground—These pins supply the reference for DAQ device
digital signals and are tied to the module digital ground.
25
SERDATIN
Input
Serial Data In—The DAQ device uses this signal to program modules
in all slots.
26
SERDATOUT
Output
Serial Data Out—A cabled module uses this signal to return data
from any module to the DAQ device.
27
DAQD*/A
Input
DAQ Device Data/Address Line—The DAQ device asserts this signal
to indicate to the module whether the incoming serial stream is data
or address information.
29
SLOT0SEL*
Input
Slot 0 Select—The DAQ device asserts this signal low to indicate that
the SERDATIN line information is going to the Slot 0 controller
instead of a module.
36
SCANCLK
Input
Scan Clock—A rising edge indicates to the scanned SCXI module
that the DAQ device has taken a sample and causes the module to
advance channels.
37
SERCLK
Input
Serial Clock—This signal clocks the data on the SERDATIN and
SERDATOUT lines.
43, 46
RSVD
Input
Reserved
All other pins are not connected.
* means that the signal is asserted low.
