National Instruments cFP-RLY-421 Compact FieldPoint Relay Module

National Instruments cFP-RLY-421 Compact FieldPoint Relay Module

• Type: Form A
• Electromechanical Relays: 8
• Maximum Output: 120 VDC, 250 VAC
• Output Current Rating: 1.5A
• Separate Ground Plane per Channel

Part Number: 185151B-02, 185151C-02, 185151D-02L, 777318-421

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Stock # 73688-4
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National Instruments cFP-RLY-421 / cFP-RLY-423 Compact FieldPoint Relay Modules

  • 4 or 8 Electromechanical Relays
  • Switch 250 VAC, 120 VDC
  • Switch 1.5 A, Maximum
  • 2,300 Vrms Bank Isolation for Transient Overvoltage Protection
  • Hot Swappable with Autoconfiguration
  • -40 to 55°C Operating Range (cFP-RLY-421)
  • -40 to 60°C Operating Range (cFP-RLY-423)


The National Instruments cFP-RLY-421 / 423 devices are versatile relay modules for Compact FieldPoint that can be used to control digital signals ranging from low voltage to 120 VDC and to 250 VAC. These modules are commonly used to control indicator lights, motors, and power circuits. All the modules include onboard diagnostics to ensure trouble-free installation and maintenance.

NI cFP-RLY-421 / 423 modules provide built-in module-to-module isolation to protect your Compact FieldPoint system and controller from high voltage levels. Each channel on the cFP-RLY-421 / 423 uses electrically isolated output relays so that each relay output has a separate ground plane and each channel can be used with a different voltage potential. Thus, you can connect one channel to a 24 VDC and another channel on the same module to a 250 VAC. All the channels on the relay modules feature LEDs that indicates the output state of each channel. The modules all feature a maximum switching frequency of 10 Hz (20 operations). Overall data throughput depends on software loop speeds and network speeds.

The cFP-RLY-421 / 423 modules feature optical bank isolation with 2,300 Vrms of breakdown isolation. In addition, the modules provide double insulation for up to 250 Vrms of operational isolation. Compact FieldPoint can safely be used in applications where hazardous voltages are present with the cFP-CB-1 connector block. These Compact FieldPoint modules do not have channel-to-channel isolation. Power Requirements Because the cFP-RLY-421 / 423 are high power consumption modules, they could limit the number of I/O modules that you can connect to a single network interface module. Controllers and network interface modules supply up to 9 W to power I/O modules. The RLY-421 requires up to 2.5 W and the RLY-423 requires up to 1.5 W.

Product Family: cFP-RLY-421, cFP-RLY-423, cFP-RLY-42x, cFPRLY-421, cFPRLY-423

Important Notice: Please note that any additional items included with this equipment such as accessories, manuals, cables, calibration data, software, etc. are specifically listed in the above stock item description and/or displayed in the photos of the equipment. Please contact one of our Customer Support Specialists if you have any questions about what is included with this equipment or if you require any additional information.

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National Instruments cFP-RLY-421 / cFP-RLY-423 Compact FieldPoint Relay Modules

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