Anonymous Verified Buyer
" Very responsive and helpful, competitive pricing. Good source! "
July 2025
NI-9421
NI-9421, 8-Channel, Spring / Screw / D-SUB Connector Options, C Series Digital Module
Actual item may vary if no part number is provided on quote request.
✔ 2 Year Warranty Included
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✔ NIST Calibration Available
Expert Insights for the NI-9421
"The NI 9421 is a compact industrial current sinking device. It is a good choice for any industrial testing setup that consists of switches and transducers. This device is compatible with 24 V applications and features easy-to-read LED indicators, taking the guess work out of verifying your digital inputs."
- Chris B.
LabVIEW Trained
In-House Technician
Andrew Gar**** Verified Buyer
" Amazing to work with and had my order within 1 week after purchasing with all NI certs and data that were needed. "
March 2025
Said Sai**** Verified Buyer
" Competent contact for highly specialized components. The support team is very knowledgeable. Many thanks for the help and the fast shipping! "
January 2025
Bob C**** Verified Buyer
" Jason was able to get our emergency situation taken care of quickly and professionally. "
May 2025
Gregg Flecki**** Verified Buyer
" Great service and great products. This is my 2nd time using Apex Waves, truly impressed. "
January 2025
Carol Zimme**** Verified Buyer
" Very responsive and helpful, competitive pricing. Good source! "
July 2025
Andrew Gar**** Verified Buyer
" Amazing to work with and had my order within 1 week after purchasing with all NI certs and data that were needed. "
March 2025
Said Sai**** Verified Buyer
" Competent contact for highly specialized components. The support team is very knowledgeable. Many thanks for the help and the fast shipping! "
January 2025
Bob C**** Verified Buyer
" Jason was able to get our emergency situation taken care of quickly and professionally. "
May 2025
Gregg Flecki**** Verified Buyer
" Great service and great products. This is my 2nd time using Apex Waves, truly impressed. "
January 2025
Expert Insights for the NI-9421
"The NI 9421 is a compact industrial current sinking device. It is a good choice for any industrial testing setup that consists of switches and transducers. This device is compatible with 24 V applications and features easy-to-read LED indicators, taking the guess work out of verifying your digital inputs."
- Chris B.
LabVIEW Trained
In-House Technician
National Instruments NI-9421 C Series Digital Module
The NI 9421 (Part Numbers: 779002-01, 779136-01, 779136-02, 783734-01, 779136-02) belongs to the C Series and is a Digital Module, which works with industrial logic levels to connect specifically to a wide range of devices, transducers, and industrial switches. In addition, the NI-9421 has 8 digital input channels and Sinking Inputs. Each channel is compatible with 24 V digital I/O logic levels. To show the condition of the channel, there is an LED indicator. This module offers separation between the input channels and earth ground.
There are four variations of the NI-9421 module—part number 779002-01 is the version of the device equipped with screw terminals, which has 250 Vrms Ch-Earth Ground Isolation. Part numbers 779136-01 and 779136-02 both feature D-SUB connectors and have 60 VDC Ch-Earth Ground Isolation. The difference between these two numbers is that part number 779136-02 is conformal coated. Lastly, part number 783734-01 has Spring Terminal front connectors and 250 Vrms Ch-Earth Ground Isolation. The NI C Series Digital Module has a power consumption value of up to 240 mW when active, and 7 mW maximum when in sleep mode.
The digital input provide a route to COM to the energy or voltage. The NI-9421 possess sinking inputs, which sends a message that the external gadget is driving current or applies voltage to the DI terminal or stick. The current signals associated with DI are limited by the NI-9421. If an application utilizing the module with screw terminals is liable to high vibration, it is recommended by the manufacturer National Instruments for the user utilize ferrules to end wires to the separable screw-terminal connector or utilize a backshell connector for added protection. This module additionally has a low-power rest mode.
The NI device has recommended operating and storage temperature ranges of -40 °C to 70 °C and -40 °C to 85 °C, non-condensing operating and storage humidity ranges of 10% RH to 90% RH and 5% RH to 95% RH, random and sinusoidal operating vibrations of 5 grms and 5 g respectively–all at a frequency range of 10 to 500 Hz.
| Model | NI-9421 |
|---|---|
| Manufacturer | National Instruments |
| Part Numbers | 783734-01, 779002-01, 779136-01, 779136-02 |
| Type | C Series Digital Module |
| Digital Input Channels | 8 |
| Digital I/O Logic Levels | 12V, 24V |
| Maximum Update Rate | 100 us |
| Front Connector | Spring Terminal, Screw Terminal, or D-SUB |
| Digital Input Type | Sinking |
| Maximum Power Consumption | 240 mW (Active), 7 mW (Sleep) |
| Maximum Thermal Dissipation | 1.3 W (Active), 1.1 W (Sleep) |
| Screw Terminal Wiring Gauge | 26 AWG to 14 AWG |
| Digital I/O Isolation | 250 Vrms Ch-Earth Ground Isolation or 60 VDC Ch-Earth Ground Isolation |
| Operating Temperature | -40 °C to 70 °C |
| Storage Temperature | -40 °C to 85 °C |
| Weight | Screw Terminal: 5.9 oz (166 g) Spring Terminal: 5.4 oz (153 g) D-SUB: 5.0 oz (144 g) |
| NI-9421 Manual | User Manual and Maintenance Manual Available for Download |
| Price | Request a Quote Today for More Information |
Associated part numbers for NI-9421:
National Instruments NI-9421 Frequently Asked Questions
Question: What is the input voltage I/O protection for the NI-9421?
Answer: The input voltage I/O protection is 40 V maximum.
Question: What is the wiring compatibility of the NI-9421?
Answer: The wiring compatibility of the Digital Module is with 2-, 3-, and 4-wire sourcing-output devices.
Question: How much power does the NI-9421 consume?
Answer: The C Series Digital Module has a maximum power consumption of 240 mW when in active mode and 7 mW when in sleep mode.
Question: Which backshell connector can be used with the NI 9421?
Answer: The screw terminal version of the device can be used with the NI 9927 backshell kit. The spring terminal version can be used with the NI-9981 backshell kit, and the D-SUB version can be used with the NI-9932 backshell kit.
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