PXI-6521

16-Channel, ±30 VDC, 8 Sink/Source Inputs, 8 Relay Outputs, Isolated PXI Digital I/O Module—The PXI‑6521 is an industrial digital I/O module with high channel isolation and industry-standard 24 V logic levels.  For added safety, the PXI‑6521 requires a keyed connector. If a computer or application fault occurs, the PXI‑6521 can use digital I/O watchdogs to switch to a configurable safe output state to ensure detection and safe recovery from fault conditions. It also features programmable power-up states, digital filtering, and change detection for optimal control over your application.