The National Instruments PCIe-6251 is a 16-bit multifunction data acquisition device built on the PCI Express bus for laboratory automation, research, design verification, and manufacturing test. It delivers analog input sampling to 1.25 MS/s on single channels with 16 single-ended or 8 differential input channels, plus dual 16-bit analog outputs, 24 digital I/O lines, and two 32-bit counters operating at 80 MHz. NI-MCal calibration technology and the NI-PGIA 2 amplifier ensure 16-bit measurement accuracy at maximum speed, with 100 dB CMRR and low crosstalk performance across all channels.
Technical Specifications
Analog Inputs
• 16 single-ended or 8 differential channels
• 16-bit resolution
• 1.25 MS/s single-channel; 1.00 MS/s multichannel aggregate sample rate
• Programmable input ranges: ±10 V, ±5 V, ±2.0 V, ±1.0 V, ±0.5 V, ±0.2 V, ±0.1 V (all inputs share same range)
• 100 dB CMRR; -95 dB crosstalk (non-adjacent), -75 dB (adjacent channels)
• Accuracy valid up to two years from external calibration within 10 °C of last calibration
Analog Outputs
• 2 channels; 16-bit DAC resolution
• 2.86 MS/s (single channel); 2.00 MS/s (dual channel) update rate
• Output ranges: ±10 V, ±5 V (shared across all outputs)
• DNL correction and overdrive protection
Digital I/O
• 24 bi-directional TTL/CMOS lines with 8 correlated DIO channels
Counters/Timers
• Two 32-bit counters at 80 MHz timebase
• Quadrature encoder support (1X, 2X, 4X, non-quadrature); no encoder filtering
• 2 × 32-bit PWM outputs (counter-based, 80 MHz timebase)
Triggering
• Analog and digital triggering with 10-bit precision
• Start, reference, and pause trigger modes
Bus Interface
• PCI Express; 250 MB/s per direction bandwidth
– Key Features
• NI-MCal calibration for enhanced measurement precision
• NI-PGIA 2 amplifier for fast settling at high scanning rates
• Per-channel programmable input gains
• Simultaneous analog I/O capability
– Typical Applications
Laboratory automation, research instrumentation, design verification, manufacturing test environments.
– Compatibility & Integration
Designed as part of the National Instruments M Series DAQ family with PCI Express connectivity.
