National Instruments NI 9472 User manual

OPERATING INSTRUCTIONS AND SPECIFICATIONS
NI 9472/9474
8-Channel Digital Output Modules
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NI 9472/9474 2 ni.com
This document describes how to use the National Instruments 9472
and National Instruments 9474 and includes specifications and
terminal or pin assignments. In this document, the NI 9472/9474
with screw terminal and NI 9472 with DSUB are referred to
inclusively as the NI 9472/9474. Visit ni.com/info and enter
rdsoftwareversion to determine which software youneed for
the modules youare using. For information about installing,
configuring, and programming the system, refer to the system
documentation. Visit ni.com/info and enter cseriesdoc for
information about C Series documentation.
Note The safety guidelines and specifications in this
document are specific to the NI 9472/9474. The other
components in the system might not meet the same safety
ratings and specifications. Refer to the documentation for
each component in the system to determine the safety
ratings and specifications for the entire system. Visit
ni.com/info and enter cseriesdoc for information
about C Series documentation.
Safety Guidelines
Operate the NI 9472/9474 only as described in these operating
instructions.

© National Instruments Corp. 3 NI 9472/9474
Hot Surface This icon denotes that the component may be
hot. Touching this component may result in bodily injury.
Safety Guidelines for Hazardous Voltages
Yo ucan connect hazardous voltages only to the NI 9472/9474 with
screw terminal. Do not connect hazardous voltages to the NI 9472
with DSUB.
If hazardous voltages are connected to the module, take the
following precautions. A hazardous voltage is a voltage greater
than 42.4 Vpk or 60 VDC to earth ground.
Caution Ensure that hazardous voltage wiring is
performed only by qualified personnel adhering to local
electrical standards.
Caution Do not mix hazardous voltage circuits and
human-accessible circuits on the same module.
Caution Make sure that devices and circuits connected to
the module are properly insulated from human contact.
Caution When module terminals are hazardous voltage
LIVE (>42.4 Vpk/60 VDC), youmust ensure that devices

NI 9472/9474 4 ni.com
and circuits connected to the module are properly
insulated from human contact. Youmust use the NI 9932
connector backshell kit to ensure that the terminals are
not accessible.
Figure 1 shows the NI 9932 connector backshell.
Note Yo ucan use the NI 9932 connector backshell only
with the NI 9472/9474 with screw terminal.
Figure 1. NI 9932 Connector Backshell

© National Instruments Corp. 5 NI 9472/9474
Safety Guidelines for Hazardous Locations
The NI 9472/9474 is suitable for use in Class I, Division 2,
Groups A, B, C, D, T4 hazardous locations; Class I, Zone 2,
AEx nC IIC T4 and Ex nC IIC T4 hazardous locations; and
nonhazardous locations only. Follow these guidelines if youare
installing the NI 9472/9474 in a potentially explosive environment.
Not following these guidelines may result in serious injury or death.
Caution Do not disconnect I/O-side wires or connectors
unless power has been switched off or the area is known
to be nonhazardous.
Caution Do not remove modules unless power has been
switched off or the area is known to be nonhazardous.
Caution Substitution of components may impair
suitability for Class I, Division 2.
Caution For Zone 2 applications, install the system in an
enclosure rated to at least IP 54 as defined by IEC 60529
and EN 60529.

NI 9472/9474 6 ni.com
Caution For Zone 2 applications, install a protection
device between the Vsupand COM terminals on the
NI 9472/9474. The device must prevent the input
Vsup-to-COM voltage from exceeding 42 V if there is a
transient overvoltage condition.
Special Conditions for Hazardous Locations Use in Europe
This equipment has been evaluated as EEx nC IIC T4 equipment
under DEMKO Certificate No. 03 ATEX 0324020X. Each module
is marked II 3G and is suitable for use in Zone 2 hazardous
locations. If youare using the NI 9472/9474 in Gas Group IIC
hazardous locations or in ambient temperatures of
–40 °C ≤Ta ≤70 °C, youmust use the device in an NI chassis that
has been evaluated as EEx nC IIC T4, Ex nA IIC T4, or
Ex nL IIC T4 equipment.

© National Instruments Corp. 7 NI 9472/9474
Special Conditions for Marine Applications
Some modules are Lloyd’s Register (LR) Type Approved for
marine applications. To verify Lloyd’s Register certification, visit
ni.com/certification and search for the LR certificate, or
look for the Lloyd’s Register mark on the module.
Caution To meet radio frequency emission requirements
for marine applications, use shielded cables and install
the system in a metal enclosure. Suppression ferrites
must be installed on power supply inputs near power
entries to modules and controllers. Power supply and
module cables must be separated on opposite sides of the
enclosure and must enter and exit through opposing
enclosure walls.

NI 9472/9474 8 ni.com
Connecting the NI 9472/9474
The NI 9472/9474 provides connections for eight digital output
channels.
Figure 2. NI 9472/9474 Terminal and Pin Assignments
DO0
DO1
DO2
DO3
DO4
DO5
DO6
DO7
Vsup
COM
0
1
2
3
4
5
6
7
8
9
COM
Vsup
COM
COM
Vsup
COM
COM
Vsup
COM
COM
Vsup
COM
COM
DO0
Vsup
DO1
DO2
Vsup
DO3
DO4
Vsup
DO5
DO6
Vsup
DO7
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
03
47
03
47

© National Instruments Corp. 9 NI 9472/9474
The NI 9472/9474 with screw terminal has a 10-terminal,
detachable screw-terminal connector. The NI 9472 with DSUB has
a 25-pin DSUB connector. Each channel of the NI 9472/9474 has
a terminal or pin, DO, to which youcan connect a device. The
eight digital output channels are internally referenced to the
common terminal or pin, COM. National Instruments recommends
youprovide independent COM and Vsup wiring for each channel of
the NI 9472 with DSUB to minimize current flow in the COM and
Vsup wiring. The COM pins on the NI 9472 with DSUB are
internally connected..
Note Yo umust use 2-wire ferrules to create a secure
connection when connecting more than one wire to a
single terminal on the NI 9472/9474 with screw terminal.
Each channel has an LED that indicates the state of the channel.
When a channel LED is lit, the channel is on. When the LED is
dark, the channel is off. The LEDs are disabled when the chassis is
in sleep mode. Refer to the Sleep Mode section for more
information about sleep mode.

NI 9472/9474 10 ni.com
Yo umust connect an external power supply to the NI 9472/9474.
This power supply provides the current for the devices youconnect
to the module. Connect the positive lead of the power supply to
Vsupand the negative lead of the power supply to COM. The Vsup
pins on the NI 9472 with DSUB are internally connected. Youcan
connect only one external voltage supply to the device. Refer to the
Specifications section for information about the power supply
voltage range.
Caution Do not remove or insert modules if the external
power supply connected to the Vsupand COM pins is
powered on.
The NI 9472/9474 has current sourcing outputs, meaning the DO
terminal or pin is driven to Vsupwhen the channel is turned on.

© National Instruments Corp. 11 NI 9472/9474
Yo ucan directly connect the NI 9472/9474 to a variety of industrial
devices such as solenoids, motors, actuators, relays, and lamps.
Make sure the devices youconnect to the NI 9472/9474 are
compatible with the output specifications of the module. Refer to
the Specifications section for more information about the output
specifications.
Connect the device to DO and connect the common of the device
to COM. Refer to Figure 3 for an illustration of how to connect a
device to the NI 9472/9474.
Figure 3. Connecting a Device to the NI 9472/9474
External
Power
Supply
NI 9472/9474
+
_
COM
Vsup
Device
DO

NI 9472/9474 12 ni.com
Increasing Current Drive
Each channel of the NI 9472 has a continuous output current of
0.75 A, and each channel of the NI 9474 has a continuous output
current of 1 A. If youwant to increase the output current to a
device, youcan connect any number of channels together in
parallel. For example, using the NI 9474, if youwant to drive 4 A
of current, connect DO<0...3> in parallel as shown in Figure 4.
Yo umust turn all parallel channels on and off simultaneously so
that the current on any single channel cannot exceed the 1 A rating.
Figure 4. Increasing the Current to a Device Connected to the NI 9474
NI 9474
DO3
DO1
DO0
DO2
4 A
+
_
COM
1 A
1 A
1 A
1 A
External
Power
Supply
Device
V
sup

© National Instruments Corp. 13 NI 9472/9474
Wiring for High-Vibration Applications
If an application using the NI 9472/9474 with screw terminal is
subject to high vibration, National Instruments recommends that
youeither use ferrules to terminate wires to the detachable
screw-terminal connector or use the NI 9932 backshell kit to
protect the connections. Refer to Figure 5 for an illustration of
using ferrules. Refer to Figure 1 for an illustration of the NI 9932
connector backshell.
Figure 5. 10-Terminal Detachable Screw-Terminal Connector with Ferrule

NI 9472/9474 14 ni.com
I/O Protection
The NI 9472/9474 is short-circuit proof in accordance with
IEC 1131-2 and provides overcurrent protection.
Understanding Short-Circuit-Proof Devices
Each channel on the NI 9472/9474 has circuitry that protects it
from current surges resulting from short circuits. Whether the
module suffers damage from these overcurrent conditions depends
on the following factors:
• The amount of current through the channel
• The amount of time the current is above the current limit
• The frequency of the current surges
When the amount of current through the DO terminal or pin is
greater than 13 A, the channel trips and goes into an overcurrent
state. In an overcurrent state, the channel turns off and the module
is not damaged. If the current through DO is between 6 A and 13 A,
the state of the channel is indeterminate and depends on factors
such as the current level, the temperature, and the power supply.
Higher inrush currents that exist for less than the trip time do not
trip the protection circuitry. Refer to the Specifications section for

© National Instruments Corp. 15 NI 9472/9474
more information about the maximum continuous output current,
short-circuit behavior, and short-circuit trip time. Youalso can
refer to the IEC 1131-2 standard for more information about
short-circuit-proof devices.
Tip Because the NI 9472/9474 module includes internal
flyback diodes, youdo not need to add external diodes
when connecting to switching energy storing devices.
Power Supplies and Overcurrent Conditions
If a short-circuit occurs, the current through DO can exceed the
current rating for the power supply and the maximum continuous
output current for the NI 9472/9474.
If the power supply youare using with the NI 9472/9474 cannot
supply more than 13 A, the module may be damaged if a
short-circuit condition occurs.
Detecting an Overcurrent Condition
If a device connected to the module is not working while the
channel is on, the module channel may be in an overcurrent state.
Neither the software nor the module LEDs indicate if an
overcurrent condition occurs. A channel LED may be on even if the
channel is off because of an overcurrent condition. To determine if

NI 9472/9474 16 ni.com
the channel is in an overcurrent state, measure the voltage between
DO and Vsup. If the voltage is equal to the voltage of the external
power supply connected to the module, the channel is in an
overcurrent state.
Resetting Channels After an Overcurrent Condition
After youhave determined and fixed the cause of the overcurrent
condition, reset the channel by turning it off. Alternatively, youcan
disconnect the external power supply from the module. However,
doing so disconnects power from all of the module channels.
Normal operation can resume after youcorrect the overcurrent
condition and reset the channel.
Sleep Mode
This module supports a low-power sleep mode. Support for sleep
mode at the system level depends on the chassis that the module is
plugged into. Refer to the chassis manual for information about
support for sleep mode. If the chassis supports sleep mode, refer to
the software help for information about enabling sleep mode. Visit
ni.com/info and enter cseriesdoc for information about
C Series documentation.

© National Instruments Corp. 17 NI 9472/9474
Typically, when a system is in sleep mode, youcannot
communicate with the modules. In sleep mode, the system
consumes minimal power and may dissipate less heat than it does
in normal mode. Refer to the Specifications section for more
information about power consumption and thermal dissipation.
Specifications
The following specifications are typical for the range –40 to 70 °C
unless otherwise noted. All voltages are relative to COM unless
otherwise noted. The specifications are the same for the NI 9472
and the NI 9474 unless otherwise noted.
Output Characteristics
Number of channels.......................... 8 digital output channels
Output type ....................................... Sourcing
Power-on output state ....................... Channels off
External power supply voltage range (Vsup)
NI 9472....................................... 6–30 VDC
NI 9474....................................... 5–30 VDC

NI 9472/9474 18 ni.com
Output impedance (R0)
Typical ........................................ 0.07 Ω
Maximum ................................... 0.13 Ω
Continuous output current (I0), per channel
NI 9472....................................... 0.75 A max
NI 9474....................................... 1 A max
Output voltage (V0)........................... Vsup – (I0· R0)
I/O protection
Voltage........................................ 30 VDC max
Reversed voltage ........................ None
Short-circuit behavior
Short-circuit trip time ................. 10 μs at 13 A
Current Channel Behavior Module Protection
0 to 1 A Channel does not trip Module is not damaged
1 to 6 A Channel does not trip Module may be damaged
6 to 13 A Channel may trip Module may be damaged
>13 A Channel trips Module is not damaged

© National Instruments Corp. 19 NI 9472/9474
Output delay time (full load)
NI 9472....................................... 100 μs max
NI 9474....................................... 1 μs max
MTBF
NI 9472....................................... 1,113,301 hours at 25 °C;
Bellcore Issue 2, Method 1,
Case 3, Limited Part Stress
Method
NI 9474....................................... 479,889 hours at 25 °C;
Bellcore Issue 2, Method 1,
Case 3, Limited Part Stress
Method
Note Contact NI for Bellcore MTBF specifications
at other temperatures or for MIL-HDBK-217F
specifications.
NI 9472 Power Requirements
Power consumption from chassis
Active mode ............................... 230 mW max
Sleep mode ................................. 0.4 mW max

NI 9472/9474 20 ni.com
Thermal dissipation (at 70 °C)
Active mode ............................... 1.5 W max
Sleep mode ................................. 55 mW max
NI 9474 Power Requirements
Power consumption from chassis
Active mode ............................... 660 mW max
Sleep mode ................................. 0.6 mW max
Thermal dissipation (at 70 °C)
Active mode ............................... 1.5 W max
Sleep mode ................................. 0.6 mW max
Physical Characteristics
If youneed to clean the module, wipe it with a dry towel.
Screw-terminal wiring ...................... 12 to 24 AWG copper
conductor wire with 10 mm
(0.39 in.) of insulation
stripped from the end
Torque for screw terminals ............... 0.5 to 0.6 N · m
(4.4 to 5.3 lb · in.)