National Instruments PXI-4220

The National Instruments PXI-4220 (Part Number: 778745-4220) is a highly capable 16-bit, 2-channel PXI Strain/Bridge Input Module designed for applications involving full-, quarter-, and half-bridge sensors, including load cells and pressure sensors. It supports a maximum sample rate of 333 kS/s and offers fully programmable channel-specific excitation, bridge configurations, filtering, and amplification. The module features a concurrent sample-and-hold capability that effectively eliminates inter-channel phase delays, ensuring high measurement fidelity. Each input channel is equipped with a 9-pin D-SUB connector for rapid connectivity to programmable shunts and bridge connectors, facilitating enhanced measurement precision through offset and gain error elimination.

Users can easily adjust the voltage excitation level via software, utilizing pins 2 and 7 to set excitation magnitudes. In addition, a lowpass filter allows users to select from multiple cutoff frequencies, including options for 10 Hz, 100 Hz, 1 kHz, or 10 kHz to optimize signal integrity. The module incorporates a 4-pole Butterworth filter per channel with four software-selectable cutoff frequencies, significantly improving signal accuracy while minimizing noise interference. Time base options include an external source through the PXI trigger bus or an internal 20 MHz master clock, complemented by a PXI trigger bus featuring one star trigger and six trigger lines. The integrated amplifier maintains a DC input impedance greater than 1 GΩ, with a maximum input bias current of ±20 nA.

The PXI-4220 is compatible with the NIDAQmx driver software (version 7.0 or later) and can be programmed using popular application development environments like LabVIEW, LabWindows/CVI, or Measurement Studio. The module's dimensions are 6.3 x 3.9 x 0.79 inches, and it operates effectively within a temperature range of 0 to 55 °C, while offering storage capabilities from –20 to 70 °C with a humidity tolerance of 10 to 90% RH. Although the PXI-4220 has been designated as obsolete by National Instruments, it remains available for purchase and repair through Apex Waves, ensuring continued access to this high-performance input module.