The National Instruments PXI-4351 (Part Number: 777790-01) is a high-precision digitizer designed for accurate measurement applications. Equipped with a 24-bit Sigma-Delta Analog-to-Digital Converter, this device supports differential analog inputs and can perform temperature measurements using thermistors and resistance temperature detectors (RTDs), as well as ohm and current measurements through integrated precision current sources and external shunt resistors. The PXI-4351 features 16 voltage and 14 thermocouple channels, making it suitable for a variety of sensors and measurement tasks.

With a built-in 1 mA precision current source, the digitizer can accurately measure resistances up to 15 kΩ. It also includes programmable TTL-compatible digital I/O for monitoring TTL-level inputs. The low leakage construction, combined with digital and analog filtering capabilities, ensures excellent accuracy, noise rejection, and resolution. Additionally, the software-programmable ground-referencing feature allows users to reference floating signals without compromising voltage measurements.

The PXI-4351 is compatible with various operating systems and easily interfaces with a personal computer to provide cost-effective functionality similar to standard bench-top instruments, such as digital multimeters (DMMs) and data loggers. Supported by a comprehensive user manual and maintenance guide, the PXI-4351 offers a reliable and versatile platform for high-resolution measurements. Although its obsolete status has been announced by National Instruments, the device remains available for purchase and repairs through Apex Waves.