National Instruments NI 9425 User manual

OPERATING INSTRUCTIONS AND SPECIFICATIONS
NI 9425
32-Channel, 24 V Sinking Digital Input Module
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NI 9425 Operating Instructions and Specifications 2 ni.com
This document describes how to use the National Instruments 9425
and includes specifications and pin assignments for the NI 9425.
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 9425. 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.

© National Instruments Corp. 3 NI 9425 Operating Instructions and Specifications
Safety Guidelines
Operate the NI 9425 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.
Safety Guidelines for Hazardous Voltages
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.

NI 9425 Operating Instructions and Specifications 4 ni.com
Caution When module terminals are hazardous voltage
LIVE (>42.4 Vpk/60 VDC), youmust ensure that devices
and circuits connected to the module are properly
insulated from human contact.
Safety Guidelines for Hazardous Locations
The NI 9425 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 9425 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.

© National Instruments Corp. 5 NI 9425 Operating Instructions and Specifications
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, connected signals must
be within the following limit:
Capacitance .......................... 0.03 μF max
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 9425 in Gas Group IIC hazardous
locations or in ambient temperatures of –40 °C ≤Ta ≤70 °C, you
must 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.

NI 9425 Operating Instructions and Specifications 6 ni.com
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.

© National Instruments Corp. 7 NI 9425 Operating Instructions and Specifications
Connecting the NI 9425
The NI 9425 has a 37-pin DSUB connector that provides
connections for 32 simultaneously-sampled digital input channels.
Figure 1. NI 9425 Pin Assignments
DI16
DI17
DI18
DI19
DI20
DI21
DI22
DI23
COM
COM
DI24
DI25
DI26
DI27
DI28
DI29
DI30
DI31
DI0
DI1
DI2
DI3
DI4
DI5
DI6
DI7
COM
COM
DI8
DI9
DI10
DI11
DI12
DI13
DI14
DI15
NC
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
37

NI 9425 Operating Instructions and Specifications 8 ni.com
Each channel has a DI pin to which youcan connect a digital input
signal. The NI 9425 has four common pins, COM, that are
internally connected to the isolated reference of the module.
The NI 9425 has sinking inputs, meaning that when the device
drives a current or applies a voltage to the DI pin, the pin provides
a path to COM for the current or voltage. The NI 9425 internally
limits current signals connected to DI. For more information about
input current levels, refer to the Specifications section.
Yo ucan connect 2-, 3-, and 4-wire sourcing-outputdevices to
the NI 9425. A sourcing-output device drives current or applies
voltage to the DI pin. An example of a sourcing-output device is an
open collector PNP.
Connect the sourcing-output device to the DI pin on the NI 9425.
Connect the common of the external device to the COM pin. Refer
to Figure 2 for an illustration of connecting a device to the
NI 9425.

© National Instruments Corp. 9 NI 9425 Operating Instructions and Specifications
Figure 2. Connecting a Device to the NI 9425 (Three-Wire Device Shown)
The NI 9425 channel registers as ON when the sourcing-output
device applies a voltage or drives a current that is in the input ON
range to the DI pin. The channel registers as OFF when the device
applies a voltage or drives a current that is in the input OFF range
to the DI pin. If no device is connected to the DI pin, the channel
registers as OFF. Refer to the Specifications section for more
information about the ON and OFF states.
NI 9425
+
_COM
DI
Sourcing-Output
Device
External
Power
Supply

NI 9425 Operating Instructions and Specifications 10 ni.com
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.
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.