The National Instruments SCXI-1126 Frequency Input Module (Part Number: 776572-26) is a sophisticated and isolated device from the SCXI Series designed for high-performance signal measurement. This module features eight channels equipped with frequency-to-voltage conversion circuits, allowing users to set programmable input ranges, thresholds, hysteresis, and filtering options. It supports ten selectable input frequency ranges, specifically from 250 kHz to 128 kHz, and includes four selectable, 4-pole low-pass filters with cut-off frequencies ranging from 1 Hz to 1 kHz. The output voltages from this module are multiplexed onto a single channel of a data acquisition (DAQ) instrument, facilitating the scanning and acquisition of multiple frequency and analog input signals in a single high-speed operation.

The SCXI-1126 is ideal for interfacing with frequency-generating sensors or various types of analog and digital periodic signal sources. It is designed with a 50-pin male ribbon cable rear connector and a 32-pin male DIN C front I/O connector, and can handle digital and analog input signals up to a maximum of 250 V. Each channel operates independently and is protected against input overvoltages up to 250 Vrms, ensuring the safety of connected devices whether powered on or off. Configuration is fully software programmable, enabling users to define parameters for input range, thresholds, hysteresis, and filtering through the NI-DAQmx driver software. The device is compatible with popular software suites, including LabVIEW, LabWindows/CVI, and Measurement Studio, with hardware configuration managed via the Measurement & Automation Explorer tool.

Due to the low bandwidth of the output filters, a settling time of approximately three seconds is required after modifying settings for precise measurements. The module measures 1.2 x 6.8 x 8.0 inches. While its status has been declared obsolete by National Instruments, the SCXI-1126 remains available for purchase and repair through Apex Waves.