National Instruments PCI-6521 / PXI-6521 Industrial Digital I/O Devices
Features

• 8, ±30 VDC Digital Inputs with 60 V Channel-to-Channel Isolation
• (8) Nonlatching Mechanical Relay Outputs
• 150 V AC/DC Maximum Switching Voltage with Maximum Switching Current of 2 A and Maximum Switching Power of 60 W
• High-Reliability Industrial Feature Set Includes: Isolation, Programmable Power-Up States, Digital Filtering, Watchdog Timers, and Change Detection

The National Instruments PCI-6521 / PXI-6521 Industrial Digital I/O Devices feature eight channel-to-channel isolated digital inputs and eight nonlatching mechanical relay outputs. You can use the eight differential, isolated, ±30 VDC digital inputs to read the status of sensors, actuators, and logic devices. You can use the bipolar digital input channels to read from both sinking and sourcing devices. National Instruments 6521 devices register a logic low if the voltage is between ±4 V, and they register a logic high if the voltage is less than -11 V or greater than +11 V.

These devices offer three single-pole double-throw (SPDT) Form C relays and five single-pole single-throw (SPST) Form A relays. You can use National Instruments 6521 relay outputs to switch devices requiring up to 150 V AC/DC. National Instruments 6521 relay outputs have a maximum current rating of 2 A and maximum switching power of 60 W.