NI NI-9476 User manual

NI-9476
Getting Started
2023-04-25

Contents
NI-9476 Getting Started. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
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NI-9476 Getting Started

NI-9476 Getting Started
NI-9476 Nomenclature
In this article, the NI-9476 with spring terminal and NI-9476 with DSUB are referred
to inclusively as the NI-9476. The information in this document applies to all
versions of the NI-9476 unless otherwise specified.
NI-9476 Pinout
DO16
DO17
DO18
DO19
DO20
DO21
DO22
DO23
Vsup
Vsup
DO24
DO25
DO26
DO27
DO28
DO29
DO30
DO31
DO0
DO1
DO2
DO3
DO4
DO5
DO6
DO7
Vsup
Vsup
DO8
DO9
DO10
DO11
DO12
DO13
DO14
DO15
COM
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
26
27
28
29
30
31
32
33
34
35
36
DO0
DO1
DO3
DO5
DO7
DO9
DO11
DO13
DO15
COM
DO2
DO4
DO6
DO8
DO10
DO12
DO14
COM
DO17
DO16
DO18
DO20
DO22
DO24
DO26
DO28
DO30
Vsup
DO19
DO21
DO23
DO25
DO27
DO29
DO31
Vsup
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
Table 1. Signal Descriptions
Signal Description
COM Common reference connection
DO Digital output signal connection
Vsup Voltage supply input connection
NI-9476 Block Diagram
© National Instruments 3
NI-9476 Getting Started

COM
DO
NI 9476
Vsup
Protection
Device
+
–
■ The NI-9476 has sourcing outputs. Sourcing outputs drive current from
Vsup to DO when the channel is on.
Tip For more information about sourcing outputs, visit ni.com/info and
enter the Info Code sinksource.
Connecting a Device
Connect the device to DO and COM, and connect the external power supply to Vsup
and COM.
NI 9476
+
_
COM
Vsup
Device
DO
External
Power
Supply
Common
Mode
Voltage
Note When DO is o, DO is not connected to COM. For devices with large
source impedances, you must use a pull-down resistor between DO and
COM. Visit ni.com/info and enter the Info Code CSeriesDOPulseGen for
more information.
Related information:
■Using an Info Code
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NI-9476 Getting Started

Connecting an External Power Supply
You must connect an external power supply with a 6 V DC to 36 V DC voltage range to
the NI-9476. This power supply provides the current for the devices you connect to
the module. You can connect only one external voltage supply to the NI-9476.
1. Connect the positive lead of the power supply to Vsup.
2. Connect the negative lead of the power supply to COM.
Caution Do not remove or insert modules if the external power supply
connected to the Vsup and COM pins is powered on.
Connection Guidelines
■ Make sure that devices you connect to the NI-9476 are compatible with the
module specifications.
■ You must use 2-wire ferrules to create a secure connection when connecting
more than one wire to a single terminal on the NI-9476.
■ For the NI-9476 with spring terminal, push the wire into the terminal when
using a solid wire or a stranded wire with a ferrule.
■ For the NI-9476 with spring terminal, open the terminal by pressing the
push button when using stranded wire without a ferrule.
■ For CAT II measurements, you must use a power supply with isolated DC
outputs.
High-Vibration Application Connections
If your application is subject to high vibration, NI recommends that you use the
NI-9940 backshell kit to protect connections to the NI-9476 with spring terminal.
© National Instruments 5
NI-9476 Getting Started

I/O Protection
The NI-9476 is protected against overcurrent, inrush, and short-circuit conditions in
accordance with IEC 61131-2.
Each channel on the NI-9476 has circuitry that protects it from voltage and current
surges resulting from short circuits.
Caution The NI-9476 can be damaged under overvoltage and reverse
bias voltage conditions. Check the voltage specifications for all devices
that you connect to the NI-9476.
Excessive current through a DO pin causes the channel to go into an overcurrent
state. In an overcurrent state, the channel cycles o and on until the short circuit is
removed or the current returns to an acceptably low level.
Each channel has a status line that indicates in soware whether the channel is in
an overcurrent state.
Protecting the Module from Flyback Voltages
Install an external flyback diode if the NI-9476 is switching an inductive or energy-
storing device such as a solenoid, motor, or relay, and the device does not have
flyback protection.
External
Power
Supply
NI 9476
+
_
COM
Vsup
Inductive
Device
DO
Flyback
Diode
Increasing Current Drive
Each channel has a continuous output current of 250 mA. If you want to increase
the output current to a device, you can connect any number of channels together
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NI-9476 Getting Started

in parallel. For example, if you want to drive 1 A of current, connect DO<0..3> in
parallel. You must turn all parallel channels on and o simultaneously so that the
current on any single channel cannot exceed the 250 mA rating.
NI-9476
250 mA
250 mA
250 mA
250 mA
DO3
DO1
DO0
DO2
1 A +
_
Device
COM
External
Power
Supply
Vsup
© National Instruments 7
NI-9476 Getting Started
© 2023 National Instruments Corporation.