National Instruments USB-9421 User Manual And Specifications
National Instruments USB-9421 User Manual And Specifications

National Instruments USB-9421 User Manual And Specifications

8-channel, 24 v logic, sinking digital input device

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USER GUIDE AND SPECIFICATIONS
NI USB-9421
8-Channel, 24 V Logic, Sinking Digital Input Device
Introduction
This user guide describes how to use the National Instruments USB-9421
and lists the device specifications. In this user guide, the NI USB-9421 with
screw terminal and the NI USB-9421 with D-SUB are referred to
inclusively as the NI USB-9421
The NI USB-9421 data acquisition device provides a USB interface with
connections for eight digital input channels. The NI USB-9421 consists
of two components: an NI 9421 module and an NI USB-9162 carrier,
as shown in Figure 1.
NI 9421
NI USB-9162
.
Figure 1. NI USB-9421 Components
NI USB-9421

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Summary of Contents for National Instruments USB-9421

  • Page 1 8-Channel, 24 V Logic, Sinking Digital Input Device This user guide describes how to use the National Instruments USB-9421 and lists the device specifications. In this user guide, the NI USB-9421 with screw terminal and the NI USB-9421 with D-SUB are referred to...
  • Page 2 Dimensions Figures 2 and 3 show the NI USB-9421 device dimensions. Hi-Speed USB Carrier NI USB-9162 140.23 mm 120.68 mm (5.521 in.) (4.751 in.) 137.82 mm 118.26 mm (5.426 in.) (4.656 in.) 88.12 mm 25.34 mm (3.469 in.) (0.998 in.) Figure 2.
  • Page 3: Safety Guidelines For Hazardous Voltages

    Operate the NI USB-9421 only as described in these operating instructions. Note Although the NI 9421 module may have more stringent certification standards than the NI USB-9421, when used with the NI USB-9162 carrier, the combined system may be limited. Refer to the Specifications section for more details.
  • Page 4: Related Documentation

    NI-DAQmx measurement in LabVIEW using the DAQ Assistant. • VI and Function Reference»Measurement I/O VIs and Functions—Describes the LabVIEW NI-DAQmx VIs and properties. NI USB-9421 User Guide and Specifications ni.com...
  • Page 5: Measurement Studio

    Project dialog box. Find the Measurement Studio folder for the language you want to create a program in. Choose a project type. You add DAQ tasks as a part of this step. © National Instruments Corporation NI USB-9421 User Guide and Specifications...
  • Page 6: Ansi C Without Ni Application Software

    Select Start»All Programs»National Instruments»NI-DAQ»NI-DAQmx Help. The NI-DAQmx C Reference Help describes the NI-DAQmx Library functions, which you can use with National Instruments data acquisition devices to develop instrumentation, acquisition, and control applications. Select Start»All Programs»National Instruments»NI-DAQ» NI-DAQmx C Reference Help.
  • Page 7: Installing The Software

    Example Programs The NI-DAQmx CD contains example programs that you can use to get started programming with the NI USB-9421. Refer to the NI-DAQmx for USB Devices Getting Started Guide that shipped with your device, and is also accessible from Start»All Programs»National Instruments»...
  • Page 8 NI USB-9162 carrier. Press firmly on the connector side of the NI 9421 module until the latches lock the module into place, as shown in Figure 5. Figure 5. Locking Module into Place NI USB-9421 User Guide and Specifications ni.com...
  • Page 9: Led Indicator

    Figure 6. Module Dimensions in Millimeters (Inches) Connecting the NI USB-9421 to a Computer Plug one end of the USB cable into the NI USB-9421 and the other end into an available USB port on the computer. Refer to the NI-DAQmx for USB Devices Getting Started Guide that shipped with your device, and is also accessible from Start»All Programs»National Instruments»NI-DAQ,...
  • Page 10 10-terminal, detachable, high voltage, screw terminal backshell USB-9421 with 25-pin D-SUB NI 9934 25-pin D-SUB connector For more information about installing the backshell, refer to the Assembling the High Voltage Screw Terminal Backshell section. NI USB-9421 User Guide and Specifications ni.com...
  • Page 11 Each channel of the NI USB-9421 has a terminal or pin, DI, to which you can connect voltage or current signals. The NI USB-9421 also has a common terminal or pin, COM, that is internally connected to the isolated reference of the module. Each digital input channel on the NI USB-9421 has an LED that indicates the state of that channel.
  • Page 12 The NI USB-9421 has sinking inputs, meaning that when current goes through or voltage is applied to the DI terminal or pin, DI provides a path to ground for the current or voltage. The NI USB-9421 internally limits current signals connected to DI. For more information about input current...
  • Page 13: Assembling The High Voltage Screw Terminal Backshell

    NI USB-9421 Supply Figure 8. Connecting a Device to the NI USB-9421 (3-Wire Device Shown) The NI USB-9421 channel registers as ON when the sourcing-output device applies a voltage or drives a current to DI that is in the input ON range.
  • Page 14: Specifications

    Input voltage........40 V max Reverse biased voltage ....–30 V max Input current ........7 mA max, internally limited Input delay time ........100 μs max Power Requirements Power consumption from USB....500 mA, max Suspend mode........2.5 mA, max NI USB-9421 User Guide and Specifications ni.com...
  • Page 15: Bus Interface

    With D-SUB ........Approx. 245 g (8.6 oz) Safety If you need to clean the module, wipe it with a dry towel. Safety Voltages NI USB-9421 with Screw Terminal Safety Voltages Connect only voltages that are within these limits. Channel-to-COM ........30 V max Isolation Channel-to-channel ......
  • Page 16: Safety Standards

    Safety Standards The NI USB-9421 is designed to meet the requirements of the following standards of safety for electrical equipment for measurement, control, and laboratory use: •...
  • Page 17: Electromagnetic Compatibility

    Certification column. Environmental Management National Instruments is committed to designing and manufacturing products in an environmentally responsible manner. NI recognizes that eliminating certain hazardous substances from our products is beneficial not only to the environment but also to NI customers.
  • Page 18: Waste Electrical And Electronic Equipment (Weee)

    Instruments trademarks. Other product and company names mentioned herein are trademarks or trade names of their respective companies. For patents covering National Instruments products, refer to the appropriate location: Help»Patents in your software, the patents.txt file on your CD, or ni.com/patents.

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