The NI 6509, NI 651x, NI 6528 and NI 6529 low-cost digital I/O boards deliver a high-reliability industrial feature set that includes programmable power-up states, programmable input filters, watchdog timers, change detection and industrial certifications. These boards are available for the PCI and PXI/CompactPCI platforms.
The NI 651x family offers guaranteed 24V logic levels and optical isolation in banks of 8 channels with a ±30 VDC range. The NI 6528 and NI 6529 offers channel-channel optical isolation to eliminate ground loops and a ±60 VDC range. You can use programmable power-up states on each digital I/O device to configure the initial digital state in software, which ensures safe operation when controlling industrial actuators such as pumps, valves, motors and relays. Programmable input filters eliminate noise on inputs, remove glitches and spikes, and provide debouncing for digital switches and relays. Digital I/O watchdogs protect against a variety of fault conditions such as computer and application crashes1. These features are especially valuable for mission-critical industrial automation and control applications.
1 Note that the NI-DAQmx Watchdog feature is meant to protect a system from software errors and hangs. In the case of a PXI system with remote control via MXI, a lost MXI connection could result in unexpected Watchdog behavior and therefore improperly implemented Watchdog states.