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Conventions
The following conventions are used in this manual:
<>Angle brackets that contain numbers separated by an ellipsis represent
a range of values associated with a bit or signal name—for example,
AO <3. .0>.
»The » symbol leads you through nested menu items and dialog box options
to a final action. The sequence File»Page Setup»Options directs you to
pull down the File menu, select the Page Setup item, and select Options
from the last dialog box.
This icon denotes a note, which alerts you to important information.
This icon denotes a caution, which advises you of precautions to take to
avoid injury, data loss, or a system crash.When this symbol is marked on a
product, refer to the Read Me First: Safety and Radio-Frequency Interference documentfor information about precautions to take.
When symbol is marked on a product, it denotes a warning advising you to
take precautions to avoid electrical shock.
When symbol is marked on a product, it denotes a component that may be
hot. Touching this component may result in bodily injury.
boldBold text denotes items that you must select or click in the software, such
as menu items and dialog box options. Bold text also denotes parameter
names.
italicItalic text denotes variables, emphasis, a cross-reference, or an introduction
to a key concept. Italic text also denotes text that is a placeholder for a word
or value that you must supply.
monospaceText in this font denotes text or characters that you should enter from the
keyboard, sections of code, programming examples, and syntax examples.
This font is also used for the proper names of disk drives, paths, directories,
programs, subprograms, subroutines, device names, functions, operations,
variables, filenames, and extensions.
Contents
Chapter 1
About the SCXI-1141/1142/1143
What You Need to Get Started ......................................................................................1-2
National Instruments Documentation ............................................................................1-3
Installing Application Software, NI-DAQmx, and the DAQ Device ............................1-4
Installing the SCXI-1141/1142/1143 into an SCXI Chassis or
a PXI/SCXI Combination Chassis................................................................1-4
Installing the Terminal Block ........................................................................................1-4
Verifying the SCXI-1141/1142/1143 Installation in Software ......................................1-5
Installing SCXI Chassis and Modules in Software .........................................1-5
Troubleshooting the Self-Test Verification ...................................................................1-5
Troubleshooting in NI-DAQmx ......................................................................1-5
Chapter 2
Connecting Signals
Front Connector .............................................................................................................2-1
Front Connector Signal Descriptions ..............................................................2-3
Analog Input Channels......................................................................2-3
Digital Input and Output ...................................................................2-6
Rear Signal Connector ...................................................................................................2-7
Analog Output Signal Connections.................................................................2-11
Digital I/O Signal Connections .......................................................................2-11
Table 5-5.NI-DAQmx Current Measurement Properties ...................................... 5-6
Table 5-6.Programming a Task in LabVIEW ...................................................... 5-8
Table A-1.Settling Time with Respect to Cutoff Frequency ................................. A-3
Table C-1.Digital SIgnals on the SCXI-1141/1142/1143 ...................................... C-2
SCXI-1141/1142/1143 User Manualviiini.com
About the SCXI-1141/1142/1143
This chapter describes the SCXI-1141/1142/1143 module, and explains
how to install and remove the hardware and software.
The SCXI-1141/1142/1143 module has eight lowpass filters and
eight differential-input amplifiers. The SCXI-1141 has elliptic filters;
the SCXI-1142, Bessel filters; and the SCXI-1143, Butterworth filters.
You can use the SCXI-1141/1142/1143 module for lowpass filtering and
antialiasing applications as well as for general-purpose signal amplification
and filtering. The SCXI-1141/1142/1143 module works with National
Instruments E/M Series DAQ devices. You can use one DAQ device to
control several SCXI-1141/1142/1143 modules, in combination with other
SCXI modules in a chassis. Each SCXI-1141/1142/1143 module can
multiplex its channels into a single channel of the DAQ device, although
separate outputs are also available. You can multiplex the output of several
SCXI-1141/1142/1143 modules into a single channel, thus greatly
increasing the number of analog input signals that the DAQ device can
digitize.
1
The SCXI-1304 shielded terminal block has screw terminals for easily
connecting signals to the SCXI-1141/1142/1143 module and is the terminal
block recommended for use with this module.
Refer to Appendix A, Specifications, for detailed SCXI-1141/1142/1143
module specifications.
To set up and use the SCXI-1141/1142/1143 module, you need the
following:
❑ Hardware
–SCXI-1141/1142/1143 module
–One of the following terminal blocks:
•SCXI-1304
•SCXI-1305
–An SCXI chassis or PXI/SCXI combination chassis
–One of the following:
•E/M Series DAQ device
•SCXI-1600
–A computer if using an SCXI chassis
–Cabling, cable adapter, and sensors as required for your
application
❑ Software
–NI-DAQ
–One of the following software packages:
•LabVIEW
•Measurement Studio
™
•LabWindows
/CVI
™
❑ Documentation
–Read Me First: Safety and Radio-Frequency Interference
–DAQ Getting Started Guide
–SCXI Quick Start Guide
–SCXI-1141/1142/1143 User Manual
–Terminal block installation guide for your application
–Documentation for your software
You can download NI documents from
the latest version of NI-DAQmx visit
Updates. In the Product Line drop-down menu locate Multifunction
ni.com/manuals. To download
ni.com and click Drivers and
SCXI-1141/1142/1143 User Manual1-2ni.com
Chapter 1About the SCXI-1141/1142/1143
DAQ. Select the appropriate information for your application in the
remaining drop-down menus and click Go.
National Instruments Documentation
The SCXI-1141/1142/1143 User Manual is one piece of the documentation
set for data acquisition (DAQ) systems. You could have any of several
types of manuals depending on the hardware and software in the system.
Use the manuals you have as follows:
•SCXI chassis or PXI/SCXI combination chassis manual—Read this
manual for maintenance information on the chassis and for installation
instructions.
•The DAQ Getting Started Guide—This document has information on
installing NI-DAQ and the E/M Series DAQ device. Install these
before you install the SCXI module.
•The SCXI Quick Start Guide—This document contains a quick
overview for setting up an SCXI chassis, installing SCXI modules and
terminal blocks, and attaching sensors. It also describes setting up the
SCXI system in MAX.
•The SCXI hardware user manuals—Read these manuals next
for detailed information about signal connections and module
configuration. They also explain, in greater detail, how the module
works and contain application hints.
•Accessory installation guides or manuals—Read the terminal block
and cable assembly installation guides. They explain how to physically
connect the relevant pieces of the system. Consult these guides when
you are making the connections.
•The E/M Series DAQ device documentation—This documentation has
detailed information about the E/M Series DAQ device that plugs into
or is connected to the computer. Use this documentation for hardware
installation and configuration instructions, specification information
about the E/M Series DAQ device, and application hints.
•Software documentation—You may have both application software
and NI-DAQ software documentation. NI application software
includes LabVIEW, LabWindows/CVI, and Measurement Studio.
After you set up the hardware system, use either your application
software documentation or the NI-DAQ documentation to help you
write your application. If you have a large, complex system, it is
worthwhile to look through the software documentation before you
configure the hardware.
•The following help file for software information:
–Start»Programs»National Instruments»NI-DAQ»
NI-DAQmx Help
Installing Application Software, NI-DAQmx, and the
DAQ Device
Refer to the DAQ Getting Started Guide packaged with the NI-DAQmx
software to install your application software, NI-DAQmx driver software,
and the E/M Series DAQ device to which you will connect the
SCXI-1141/1142/1143. NI-DAQ 8.3 or later is recommended to configure
and program the SCXI-1141/1142/1143 module.
Note Refer to the Read Me First: Radio-Frequency Interference document before
removing equipment covers or connecting or disconnecting any signal wires.
Installing the SCXI-1141/1142/1143 into an SCXI Chassis or a PXI/SCXI
Combination Chassis
Refer to the SCXI Quick Start Guide to install the SCXI-1141/1142/1143
module.
Installing the Terminal Block
Table 1-1 shows the supported SCXI-1141/1142/1143 terminal blocks.
Refer to the SCXI Quick Start Guide and the terminal block installation
guide for more information about the terminal block.
Table 1-1. Accessories Available for the SCXI-1141/1142/1143
AccessoryDescription
SCXI-1304Screw terminal block—Mounts on the front of the SCXI-1141/1142/1143 module.
It includes AC coupling circuitry and ground referencing through a 100 KΩ bias
resistor on each channel.
SCXI-1305BNC terminal block—Mounts on the front of the SCXI-1141/1142/1143 module.
It is functionally equivalent to the SCXI-1304 terminal block.
SCXI-1141/1142/1143 User Manual1-4ni.com
Chapter 1About the SCXI-1141/1142/1143
Verifying the SCXI-1141/1142/1143 Installation in
Software
Refer to the SCXI Quick Start Guide for information on verifying the SCXI
installation.
Installing SCXI Chassis and Modules in Software
Refer to the SCXI Quick Start Guide for information on installing chassis
and modules using NI-DAQmx in software.
Troubleshooting the Self-Test Verification
If the self-test verification did not verify the chassis configuration,
complete the steps in this section to troubleshoot the SCXI configuration.
Troubleshooting in NI-DAQmx
•If you get a Verify SCXI Chassis message box showing the SCXI
chassis model number, Chassis ID: x, and one or more messages
stating Slot Number: x Configuration has module: SCXI-XXXX
or 1141/1142/1143, hardware in chassis is: Empty, take the
following troubleshooting actions:
–Make sure the SCXI chassis is powered on.
–Make sure all SCXI modules are properly installed in the chassis.
Refer to the SCXI Quick Start Guide for proper installation
instructions.
–Make sure the cable between the SCXI chassis and E/M Series
DAQ device is properly connected.
–Inspect the cable connectors for bent pins.
–Make sure you are using the correct NI cable assembly.
–Test the E/M Series DAQ device to verify it is working properly.
Refer to the E/M Series DAQ device help file for more
information.
•If you get a Verify SCXI Chassis message box showing the SCXI
chassis model number, Chassis ID: x, and the message Slot
Number: x Configuration has module: SCXI-XXXX or
1141/1142/1143, hardware in chassis is: SCXI-YYYY,
1141/1142/1143, or Empty, complete the following troubleshooting
steps to correct the error.
1.Expand NI-DAQmx Devices.
2.Right-click the SCXI chassis and click Properties to load the
3.Under the Modules tab, ensure that the cabled module is listed in
4.If the cabled module is not listed in the correct slot, complete the
•If you have more than one kind of SCXI module in the SCXI chassis,
ensure that you have the highest priority SCXI module cabled to the
E/M Series DAQ device. Refer to the SCXI Quick Start Guide to find
out which SCXI module in the chassis should be cabled to the
E/M Series DAQ device.
•After checking the preceding items, return to the Troubleshooting the
Self-Test Verification section and retest the SCXI chassis.
chassis configurator.
the correct slot.
following troubleshooting steps:
a.If the cabled module is not listed in the correct slot and the
slot is empty, click the drop-down listbox next to the correct
slot and select the cabled module. Configure the cabled
module following the steps listed in the SCXI Quick Start Guide. Click OK.
b.If another module is displayed where the cabled module
should be, click the drop-down listbox next to the correct slot
and select the cabled module. A message box opens asking
you to confirm the module replacement. Click OK. Configure
the cabled module following the steps listed in the SCXI Quick Start Guide. Click OK.
If these measures do not successfully configure the SCXI system, contact
NI. Refer to the Technical Support Information document for contact
information.
SCXI-1141/1142/1143 User Manual1-6ni.com
Connecting Signals
This chapter describes input and output signal connections to the
SCXI-1141/1142/1143 module through the front and rear signal
connectors.
Caution Connections that exceed any of the maximum ratings of input or output signals
on the SCXI-1141/1142/1143 module can damage the SCXI-1141/1142/1143 module, the
SCXIbus, any connected DAQ device, and the computer with which the DAQ device is
used. NI is not liable for any damage resulting from such signal connections.
Front Connector
Table 2-1 shows the pin assignments for the SCXI-1141/1142/1143
module front connector.
Front Connector DiagramPin NumberColumn AColumn BColumn C
32AI 0 +NCAI 0 –
Column
A B C
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
NC means no connection.
RSVD means reserved.
31NCNCNC
30AI 1 +NCAI 1 –
29NCNCNC
28A GNDNCA GND
27NCNCNC
26AI 2 +NCAI 2 –
25NCNCNC
24AI 3 +NCAI 3 –
23NCNCNC
22A GNDNCA GND
21NCNCNC
20AI 4 +NCAI 4 –
19NCNCNC
18AI 5 +NCAI 5 –
17NCNCNC
16A GNDNCA GND
15NCNCNC
14AI 6 +NCAI 6 –
13NCNCNC
12AI 7 +NCAI 7 –
11NCNCNC
10NCNCNC
9NCNCNC
8RSVDNCRSVD
7NCNCNC
6RSVDNCRSVD
5NCNCNC
4RSVDNCEXT CLK
3NCNCNC
2D GNDNCOUT CLK
1NCNCNC
SCXI-1141/1142/1143 User Manual2-2ni.com
Front Connector Signal Descriptions
PinsSignal NamesDescription
Chapter 2Connecting Signals
A32, A30, A26, A24,
A20, A18, A14, A12
C32, C30, C26, C24,
C20, C18, C14, C12
A28, A22, A16, C28,
C22, C16
A2, C8D GNDDigital ground—these pins connect to the module
A8, A6, A4, C8RSVDReserved—do not connect any signals to these pins.
C4EXT CLKExternal clock—you can use this signal to set the
C2OUT CLKOutput clock—this signal has a frequency that is
Note: All other pins are not connected.
AI+<0..7+>Positive input channels—these pins connect to the
noninverting inputs of the instrumentation amplifier
of each channel.
AI–<0..7–>Negative input channels—these pins connect to the
inverting inputs of the instrumentation amplifier of
each channel.
A GNDAnalog ground—these pins connect to the module
analog ground.
digital ground.
filter cutoff frequency.
proportional to the cutoff frequency. You can use this
signal to externally control the cutoff frequency.
Analog Input Channels
The SCXI-1141/1142/1143 module instrumentation amplifiers can reject
any common-mode voltage within their common-mode input range caused
by ground-potential differences between the signal source and the module.
In addition, the amplifiers can reject common-mode noise pickup in the
leads connecting the signal sources to the SCXI-1141/1142/1143 module.
However, you should take care to minimize noise pickup. The
common-mode rejection of the instrumentation amplifiers decreases
significantly at high frequencies. The amplifiers do not reject
normal-mode noise.
The maximum differential input voltage range of the
SCXI-1141/1142/1143 module instrumentation amplifiers is a function of
the gain of the amplifiers, G, and is equal to 5 V/G. The common-mode
input range of the SCXI-1141/1142/1143 module, however, is not a
function of gain—the differential input amplifier rejects common-mode
signals as long as the signal at both inputs is within ±5 V of the module
Caution Exceeding the differential or common-mode input voltage limits distorts input
signals. Exceeding the maximum common-mode input voltage rating can damage the
SCXI-1141/1142/1143 module, the SCXIbus, and the DAQ device. NI is not liable for any
damage resulting from such signal connections.
Note The recommended SCXI-1304 or SCXI-1305 terminal block has all necessary
circuitry for AC or DC coupling and for floating or ground-referenced signals. The
SCXI-1304 AC/DC Coupling Terminal Block Installation Guide and SCXI-1305 AC/DC
Coupling BNC Terminal Block Installation Guide have instructions for signal connection.
Figures 2-2 through 2-5 provide supplemental information on connecting signals to the
SCXI-1141/1142/1143 module.
analog ground. The inputs are protected against maximum input voltages
of up to ±15 V powered off and ±30 V powered on.
All eight channels have fully differential inputs, so you can
ground-reference the signals you measure. If the signals connected to the
differential amplified inputs are not ground referenced, connect a 100 kΩ
resistor from the negative input to ground to provide a DC path for the input
bias currents. If you do not do this, the bias currents of the instrumentation
amplifiers of the nonreferenced channels charge up stray capacitances,
resulting in uncontrollable drift and possible saturation.
Figure 2-1 illustrates how to connect a ground-referenced signal source to
an SCXI-1141/1142/1143 module channel.
IN+
IN–
SCXI-1141/1142/1143
Figure 2-1. Ground-Referenced Signal Connection
SCXI-1141/1142/1143 User Manual2-4ni.com
Chapter 2Connecting Signals
Figure 2-2 illustrates how to connect a non-referenced (floating) signal
source to an SCXI channel.
IN+
IN–
100 kΩ
SCXI-1141/1142/1143
A GND
A
Figure 2-2. Floating Signal Connection
For AC-coupled signals, connect an external resistor from the AC-coupled
input channel to ground. This provides a DC path for the amplifier input
bias current. Typical resistor values range from 100 kΩ to 10 MΩ . This
solution, although necessary, lowers the input impedance of the channel
and introduces an additional DC offset voltage proportional to the product
of the input bias current and the resistor value used. Using a 1 MΩ resistor
results in ±200 µV of offset, which is insignificant in most applications.
However, if you use larger-valued bias resistors, significant input offset can
result. Lower-valued bias resistors increase loading of the source, which
can result in gain error.
Figures 2-3 through 2-5 illustrate how to connect AC-coupled signals.
1µF
IN+
1MΩ
IN–
SCXI-1141/1142/1143
Figure 2-3. Ground-Referenced AC-Coupled Signal Connection
Figure 2-4. Ground Offset AC-Coupled Signal Connection
1 µF
100kΩ
1 MΩ
A GND
A
IN+
IN–
SCXI-1141/1142/1143
Figure 2-5. Floating AC-Coupled Signal Connection
Digital Input and Output
You can use the EXT CLK input pin on the front connector of the
SCXI-1141/1142/1143 module to control filter cutoff frequency for special
purposes. The clock should be a TTL-logic-level or CMOS-logic-level
square wave, with a frequency of less than 2.5 MHz that is 100 times the
desired cutoff frequency. The absolute maximum input voltage for the
EXT CLK pin is 5.5 V with respect to D GND; the minimum input voltage
is –0.5 V.
The OUT CLK pin on the front connector is a CMOS-logic-level output
clock, which you can configure to have a frequency that is proportional to
filter cutoff frequency.
See Chapter 4, Theory of Operation, for more details on using these
two signals.
SCXI-1141/1142/1143 User Manual2-6ni.com
Rear Signal Connector
Note If you use the SCXI-1141/1142/1143 module with a National Instruments DAQ
device and SCXI cable assembly, you do not need to read the remainder of this chapter.
If you also use the SCXI-1180 feedthrough panel, the SCXI-1343 rear screw-terminal
adapter, or the SCXI-1351 one-slot cable extender with the SCXI-1141/1142/1143
module, you should read this section.
Table 2-2 shows the pin assignments for the SCXI-1141/1142/1143 module
rear signal connector. Pins without signal labels are not connected.
Table 2-2. Rear Signal Pin Assignments
Rear Connector DiagramSignal NamePin NumberPin Number Signal Name
NC12NC
AI 0 +34AI 0 –
12
34
56
78
910
11 12
13 14
15 16
17 18
19 20
21 22
23 24
25 26
27 28
29 30
31 32
33 34
35 36
37 38
39 40
41 42
43 44
45 46
47 48
49 50
AI 1 +56A GND
AI 2 +78A GND
AI 3 +910A GND
AI 4 +1112A GND
AI 5 +1314A GND
AI 6 +1516A GND
AI 7 +1718A GND
NC1920NC
NC2122NC
NC2324DIG GND
SER DAT IN2526SER DAT OUT
DAQ D*/A2728NC
SLOT 0 SEL*2930NC
NC3132NC
DIG GND3334NC
NC3536SCAN CLK
SER CLK3738NC
NC3940NC
NC4142NC
RSVD4344NC
NC4546NC
NC means no connection.
RSVD means reserved.
SCXI-1141/1142/1143 User Manual2-8ni.com
NC4748NC
NC4950NC
Pin
Table 2-3. SCXI-1141/1142/1143 Rear Communication Signals
SCXI Signal
Name
Chapter 2Connecting Signals
In parallel output mode, channel 0 is selected at the output multiplexer and
is connected to AI 0. The seven other channels are directly connected to
AI 1 through AI 7, respectively, on the rear connector.
In multiplexed mode, the AI 0 signal pair is used for sending all eight
channels of the SCXI-1141/1142/1143, and analog signals from other
modules, to the connected E/M Series DAQ device. If the module is cabled
directly to the DAQ device, the other analog channels of the DAQ device
are unavailable for general-purpose analog input because they are
connected to the SCXI-1141/1142/1143 amplifier outputs. This means that
connecting an SCXI-1180 module to the 50-pin breakout connector of the
SCXI-1349, or other cable adapter assembly, may cause interference and
incorrect measurements when the DAQ device is cabled to the
SCXI-1141/1142/1143.
The communication signals between the DAQ device and the SCXI system
are listed in Table 2-3. If the DAQ device is connected to the
SCXI-1141/1142/1143, these digital lines are unavailable for
general-purpose digital I/O.
NI-DAQmx
Device Signal
Name
DirectionDescription
5, 7, 9,
11, 13,
15, 17
6, 8,
10, 12,
14, 16,
18
24,
33
AI <1..7>N/AOutputAnalog outputs—these pins are the
outputs of channels 1 through 7,
regardless of the scanning mode.
A GNDAI GND—Analog ground—these pins connect
to the module analog ground. They
are used as the reference points for
AI 1 + through AI 7 +.
DIG GNDD GND—Digital ground—these pins supply
the reference for E/M Series DAQ
device digital signals and connect to
the module digital ground.
25SER DAT INP0.0InputSerial data in—this signal taps into
the SCXIbus MOSI line to send
serial input data to a module or
Slot 0.
Table 2-3. SCXI-1141/1142/1143 Rear Communication Signals (Continued)
NI-DAQmx
Device Signal
Name
DirectionDescription
Pin
SCXI Signal
Name
26SER DAT OUTP0.4OutputSerial data out—this signal taps into
the SCXIbus MISO line to accept
serial output data from a module.
27DAQ D*/AP0.1InputBoard data/address line—this signal
taps into the SCXIbus D*/A line to
indicate to the module whether the
incoming serial stream is data or
address information.
29SLOT 0 SEL*P0.2InputSlot 0 select—this signal taps into
the SCXIbus INTR* line to indicate
whether the information on MOSI is
being sent to a module or Slot 0.
36SCAN CLKAI HOLD,
AI HOLD COMP
InputScan clock—a rising edge indicates
to the scanned SCXI module that the
E/M Series DAQ device has taken a
sample and causes the module to
advance channels.
37SER CLKEXT STROBE*InputSerial clock—this signal taps into
the SCXIbus SPI CLK line to clock
the data on the MOSI and MISO
lines.
43RSVDRSVDInputReserved.
Notes: All other pins are not connected.
An * means the signal is asserted low.
The signals on the rear signal connector are classified as analog output,
digital I/O, or timing I/O signals.
SCXI-1141/1142/1143 User Manual2-10ni.com
Analog Output Signal Connections
Pins 3 through 17 of the rear signal connector are analog output signal pins.
Pin 3 is the main output, and pin 4 is its reference signal. All eight channels
are multiplexed onto this output when the module is software-configured
for multiplexed scanning mode. In parallel scanning mode, the output of
pin 3 is the output of one selected channel. Channel 0 is the power-up and
reset default. When scanning multiple modules, you can also connect this
output to the SCXIbus analog bus and the analog bus will drive this output.
Pins 5, 7, 9, 11, 13, 15, and 17 are direct outputs from channels 1 through 7,
respectively. In parallel mode, all eight channels are available
simultaneously at the rear connector. Pins 6, 8, 10, 12, 14, 16, and 18 are
the reference signals for outputs 1 through 7.
Caution The SCXI-1141/1142/1143 module analog outputs are not overvoltage protected,
although they are short-circuit protected. Applying external voltage to these outputs can
result in damage to the SCXI-1141/1142/1143 module. NI is not liable for any damage
resulting from such signal connections.
Digital I/O Signal Connections
Pins 24 through 27, 29, 33, 36, 37, and 43 constitute the digital I/O lines
of the rear signal connector. Each of these pins is in one of three
categories—digital input signals, digital output signals, and timing signals.
Pins 24 and 33 are the digital ground reference for all of the DAQ device
digital signals and are tied to the module digital ground.
Chapter 2Connecting Signals
The digital input signals are pins 25, 27, 29, and 37. Each digital line
emulates an SCXIbus communication signal as follows:
•Pin 25 is SER DAT IN and is equivalent to the SCXIbus MOSI serial
data input line.
•Pin 27 is DAQ D*/A and is equivalent to the SCXIbus D*/A line.
Pin 27 indicates to the module whether the incoming serial stream on
SER DAT IN is data (DAQ D*/A = 0) or address (DAQ D*/A = 1)
information.
•Pin 29 is SLOT 0 SEL* and is equivalent to the SCXIbus INTR* line.
Pin 29 indicates whether the data on the SER DAT IN line is being sent
to Slot 0 (SLOT 0 SEL* = 0) or to a module (SLOT 0 SEL* = 1).
•Pin 37 is SER CLK and is equivalent to the SCXIbus SPI CLK line.
Pin 37 is used to clock the serial data on the SER DAT IN line into the
module registers.
The digital output signal is pin 26. Pin 26 is SER DAT OUT and is
equivalent to the SCXIbus MISO serial data output line.
The digital I/O signals of the SCXI-1141/1142/1143 module correspond
to the digital I/O lines of an E/M Series DAQ device. Table 2-4 lists the
equivalencies.
Table 2-4. SCXIbus to SCXI-1141/1142/1143 Module Rear Signal Connector
to DAQ Device Pin Equivalencies
SCXIbus Line
SCXI-1141/1142/1143
Rear Signal Connector
E/M Series
DAQ Device
MOSISER DAT INDIO0
D*/ADAQ D*/ADIO1
INTR*SLOT 0 SEL*DIO2
SPI CLKSER CLKEXT STROBE*
MISOSER DAT OUTDIO4
Note: An * means the signal is asserted low.
The digital timing signals are pins 36 and 43:
•Pin 36 is SCAN CLK, the signal used as a clock for the
SCXI-1141/1142/1143 module multiplexer counter. The DAQ device
pulses this signal at the end of each conversion if the module is in
multiplexed mode.
•Pin 43 is a reserved digital input.
SCXI-1141/1142/1143 User Manual2-12ni.com
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