National Instruments NI 9426 User manual

OPERATING INSTRUCTIONS AND SPECIFICATIONS
NI 9426
32-Channel, 24 V, Sourcing Digital Input Module
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NI 9426 Operating Instructions and Specifications 2 ni.com
This document describes how to use the National Instruments 9426
and includes specifications and pin assignments for the NI 9426.
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 9426. 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.
Safety Guidelines
Operate the NI 9426 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 9426 Operating Instructions and Specifications
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.
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 9426 is suitable for use in Class I, Division 2, Groups A, B,
C, D, T4 hazardous locations; Class I, Zone 2, AEx nA IIC T4, and

NI 9426 Operating Instructions and Specifications 4 ni.com
Ex nA IIC T4 hazardous locations; and nonhazardous locations
only. Follow these guidelines if youare installing the NI 9426 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 that prevents the Vsupvoltage from exceeding
42 V if there is a transient overvoltage condition.

© National Instruments Corp. 5 NI 9426 Operating Instructions and Specifications
Special Conditions for Hazardous Locations Use in Europe
This equipment has been evaluated as Ex nA IIC T4 equipment
under DEMKO Certificate No. 07 ATEX 0626664X. Each module
is marked II 3G and is suitable for use in Zone 2 hazardous
locations. If youare using the NI 9426 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.
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 9426 Operating Instructions and Specifications 6 ni.com
Connecting the NI 9426
The NI 9426 has a 37-pin DSUB connector that provides
connections for 32 simultaneously-sampled digital input channels.
Figure 1. NI 9426 Pin Assignments
DI16
DI17
DI18
DI19
DI20
DI21
DI22
DI23
Vsup
Vsup
DI24
DI25
DI26
DI27
DI28
DI29
DI30
DI31
DI0
DI1
DI2
DI3
DI4
DI5
DI6
DI7
Vsup
Vsup
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

© National Instruments Corp. 7 NI 9426 Operating Instructions and Specifications
Each channel has a DI pin to which youcan connect a digital input
signal. The NI 9426 has four supply pins, Vsup, that are internally
connected to the isolated reference of the module.
The NI 9426 has sourcing inputs, meaning the DI pin sources
current from Vsupto the sinking output device. The NI 9426
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 sinking-outputdevices to
the NI 9426. A sinking-output device provides a path from the
DI pin to a voltage below Vsup. An example of a sinking-output
device is an open collector NPN.
Connect the sinking-output device to the DI pin of the NI 9426.
Connect the positive power supply lead of the external device to the
Vsuppin. Refer to Figure 2 for an illustration of connecting a device
to the NI 9426.

NI 9426 Operating Instructions and Specifications 8 ni.com
Figure 2. Connecting a Device to the NI 9426 (Three-Wire Device Shown)
The NI 9426 channel registers as ON when the sinking-output
device drives the input below Vsupand meets the input ON range.
The channel registers as OFF when the device does not drive the
input low and is in the input OFF range. 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 9426
+
_DI
Vsup
Sinking-Output
Device
External
Power
Supply

© National Instruments Corp. 9 NI 9426 Operating Instructions and Specifications
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.
Specifications
The following specifications are typical for the range –40 to 70 °C
unless otherwise noted. All voltages are relative to Vsupunless
otherwise noted.
Input Characteristics
Number of channels.......................... 32 digital input channels

NI 9426 Operating Instructions and Specifications 10 ni.com
Input type .......................................... Sourcing
Digital logic levels
OFF state
Input voltage1....................... ≥ (Vsup – 5 V)
Input current......................... ≤150 μA from DI pin
ON state
Input voltage1....................... ≤ (Vsup – 10 V)
Input current......................... ≥ 330 μA from DI pin
Hysteresis
Input voltage ........................ 1.9 V min
Input current......................... 65 μA min
Input impedance................................ 30 kΩ ±5%
I/O protection (Vsup-to-channel)
Input voltage............................... 30 V max
Reverse-biased voltage............... –30 V max
1 Vsupis the external power supply voltage.