National Instruments NI 9472 User manual

OPERATING INSTRUCTIONS
NI 9472/9474
8-Channel Digital Output Modules

NI 9472/9474 Operating Instructions 2 ni.com
These operating instructions describe how to use the National
Instruments NI 9472 and the NI 9474. In this document, the
NI 9472 with screw terminal and NI 9472 with DSUB are referred
to inclusively as the NI 9472. For information about installing,
configuring, and programming the system, refer to the system
documentation. To determine which software you need for the
modules you are using, go to ni.com/info and enter the info code
rdsoftwareversion.
Note The safety guidelines and specifications in this
document are specific to the NI 9472/9474. The other
components in the system may 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.
Safety Guidelines
Operate the NI 9472/9474 only as described in these operating
instructions.
Hot Surface This icon denotes that the component may be
hot. Touching this component may result in bodily injury.

© National Instruments Corp. 3 NI 9472/9474 Operating Instructions
Safety Guidelines for Hazardous Voltages
You can connect hazardous voltages to the NI 9472 with screw
terminal and the NI 9474 only. 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 When module terminals are hazardous voltage
LIVE (>42.4 Vpk/60 VDC), you must ensure that devices
and circuits connected to the module are properly insulated
from human contact. You must use the NI 9932 connector
backshell kit to ensure that the terminals are not accessible.
Figure 1 shows the NI 9932 connector backshell.

NI 9472/9474 Operating Instructions 4 ni.com
Note You can use the NI 9932 connector backshell only
with the NI 9472 with screw terminal.
Figure 1. NI 9932 Connector
Safety Guidelines for Hazardous Locations
The NI 9472/9474 is suitable for use in Class I, Division 2, Groups
A, B, C, D, and 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 you are

© National Instruments Corp. 5 NI 9472/9474 Operating Instructions
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.
Caution For Zone 2 applications, install a protection
device between the input signal and the NI 9472/9474
input terminal. The device must prevent the input
Vsup-to-COM voltage from exceeding 42 V if there is a
transient overvoltage condition.

NI 9472/9474 Operating Instructions 6 ni.com
Special Conditions for Hazardous Locations Use in Europe
This equipment has been evaluated as EEx nC IIC T4 equipment
under DEMKO Certificate No. 02 ATEX 0324020X. Each module
is marked II 3G and is suitable for use in Zone 2 hazardous
locations.
Special Conditions for Marine Applications
Some modules are Lloyd’s Register (LR) Type Approved for
marine applications. To verify Lloyd’s Register certification, go to
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/exit through opposing
enclosure walls.

© National Instruments Corp. 7 NI 9472/9474 Operating Instructions
Wiring the NI 9472/9474
The NI 9472/9474 provides connections for eight digital output
channels. The NI 9472/9474 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 you can connect the device. Each channel has an LED that
indicates the state of the channel.
You must connect an external power supply to the NI 9472/9474.
This power supply provides the current for the devices you connect
to the module. Connect the positive lead of the power supply to the
supply terminal or pin, Vsup, and the negative lead of the power
supply to the common terminal or pin, COM. The eight digital
output channels are internally referenced to COM. Refer to Table 1
for the terminal assignments of the NI 9472 with screw terminal
and NI 9474. Refer to Figure 2 for the pin assignments of the
NI 9472 with DSUB.

NI 9472/9474 Operating Instructions 8 ni.com
Table 1. Terminal Assignments
Module Terminal Signal
0DO0
1DO1
2DO2
3DO3
4DO4
5DO5
6DO6
7DO7
8Supply (Vsup)
9Common (COM)
0
1
2
3
4
5
6
7
8
9
03
47

© National Instruments Corp. 9 NI 9472/9474 Operating Instructions
Figure 2. Pin Assignments
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

NI 9472/9474 Operating Instructions 10 ni.com
Wiring for High Vibration Applications
National Instruments recommends using ferrules for terminating
wires to the detachable screw terminal connector or using the
NI 9932 backshell kit to protect the connections when you use the
NI 9472 with screw terminal or the NI 9474 in high-vibration
applications. Refer to Figure 3 for an illustration.
Figure 3. 10-pin Detachable Screw Terminal Connector with a Ferrule
Ferrule

© National Instruments Corp. 11 NI 9472/9474 Operating Instructions
Connecting Devices to the NI 9472/9474
The NI 9472/9474 has current sourcing outputs, meaning the DO
terminal or pin drives current or applies voltage to the device to
which it is connected.
You can connect sinking-input devices, such as NPN, open
collectors, normally high, IEC negative logic, or other DC devices
to the NI 9472/9474. A sinking-input device provides a path to
ground for current or voltage. Make sure the device you connect to
the NI 9472/9474 meets the module specifications. Refer to the
Specifications section for more information about the output
specifications of the module.
Connect the device to DO on the NI 9472/9474. Connect the
common of the device to COM. Figure 4 shows a possible
configuration.

NI 9472/9474 Operating Instructions 12 ni.com
Figure 4. Connecting a Device to the NI 9472/9474
When the channel is on, the channel LED is on and the terminal or
pin associated with the channel drives a current or applies a voltage
to the device. When the channel is off, the channel LED is off and
the terminal or pin does not drive current or apply voltage to the
device. Refer to the software documentation for information about
writing to digital output channels.
External
Power
Supply
NI 9472/9474
+
_
COM
Vsup
Device
DO

© National Instruments Corp. 13 NI 9472/9474 Operating Instructions
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 documentation for information
regarding support for sleep mode functionality. You can enable
sleep mode in software. Refer to the driver software documentation
for more information.
Typically, when a system is in sleep mode, you cannot
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.
I/O Protection
The NI 9472/9474 is short-circuit proof in accordance with
IEC 1131-2 and provides overcurrent protection.

NI 9472/9474 Operating Instructions 14 ni.com
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 the guaranteed trip current for the module, 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 higher than the minimum possible trip current and
lower than the guaranteed trip current, 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
more information about the maximum continuous output current,
trip current, and trip time. You also can refer to the IEC 1131-2
standard for more information about short-circuit-proof devices.

© National Instruments Corp. 15 NI 9472/9474 Operating Instructions
Tip Because the NI 9472 and NI 9474 modules include
internal flyback diodes, you do 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 you are using with the NI 9472/9474 cannot
supply more than the guaranteed trip current, 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
though the channel is off because of an overcurrent condition. To
determine if 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.

NI 9472/9474 Operating Instructions 16 ni.com
Resetting Channels After an Overcurrent Condition
After you have determined and fixed the cause of the overcurrent
condition, reset the channel by turning it off. For more information
about writing to output channels, refer to the software
documentation. Alternatively, you can disconnect the external
power supply from the module. However, doing so disconnects
power from all of the module channels. Normal operation can
resume after you correct the overcurrent condition and reset
the channel.
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

© National Instruments Corp. 17 NI 9472/9474 Operating Instructions
Supply voltage range (Vsup)
NI 9472....................................... 6 to 30 V
NI 9474....................................... 5 to 30 V
Output voltage .................................. Vsup – (I0· R0)
Output impedance (R0) ..................... 0.13 Ωmax; 0.07 Ωtyp
Continuous output current (I0)
NI 9472....................................... 0.75 A max per channel
NI 9474....................................... 1 A max per channel
I/O protection
Voltage........................................ 30 V max
Reversed voltage ........................ None
Trip currents
Minimum possible
trip current............................ 6 A
Minimum guaranteed
trip current............................ 13 A

NI 9472/9474 Operating Instructions 18 ni.com
Trip time ..................................... 10 µs at 13 A
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 6, Method 1,
Case 3, Limited Part Stress
Method
NI 9474....................................... 479,889 hours at 25 °C;
Bellcore Issue 6, Method 1,
Case 3, Limited Part Stress
Method
Current Trips Channel Damages Module
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 Operating Instructions
Note Contact NI for Bellcore MTBF specifications
at other temperatures or for MIL-HDBK-217F
specifications. Go to ni.com/certification and
search by module number for more information about
MTBF and other product certifications.
NI 9472 Power Requirements
Power consumption from chassis
Active mode ............................... 230 mW max
Sleep mode ................................. 0.4 mW max
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

NI 9472/9474 Operating Instructions 20 ni.com
Physical Characteristics
If you need 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.)
Ferrules ............................................. 0.25 mm2to 2.5 mm2
Weight
NI 9472 with
screw terminal/NI 9474 .............. Approx. 150 g (5.3 oz)
NI 9472 with DSUB................... Approx. 145 g (5.1 oz)