National Instruments 777518-420 Relay Module for FieldPoint

 National Instruments part number 777518-420 is an identifying part number for the FP-RLY-420, a Relay Module for FieldPoint 8 SPST, non-latching normally open relays with 2.5 W Power Requirement. Each of the two relay channels on this module has two terminals: NO and IC. All Vsup and COM terminals are internally connected. For protection, a fast-acting 3 A, 250 V fuse can be installed at the IC terminal. 

This Relay Module includes eight electromechanical SPST relays. The blade's power-on state is set to "off for safe installation." When turned on, the IC and NO contacts form a short circuit with about 150 mΩ resistance between them. The NI 777518-420 has integrated protection MOVs to prevent high voltage application across the contacts and provides 250 Vrms continuous isolation between the inter-module communication bus and the backplane. This Relay Module includes high-quality relays capable of switching up to 20 times per second and handling 1 operation per second at maximum load. 

It operates with an 8 ms operate time, a 4 ms release time, and a 4 ms bound time. It offers built-in isolation between modules, safeguarding your FieldPoint system, controller, or communication interface from high voltage levels. Each channel on the RLY-420 uses electrically isolated output relays, ensuring that each relay output has its own ground plane. This design allows each channel to operate with different voltage potentials; for example, you can connect one channel to a 24 VDC signal and another channel on the same module to 250 VAC. Due to their higher power consumption, FP-RLY-42x modules may restrict the number of I/O modules you can connect to a single network interface module. Controllers and network interface modules provide up to 9 watts of power for I/O modules, while the FP-RLY-420 module itself requires up to 2.5 watts.