National Instruments 781986-27

The National Instruments 781986-27, also known as the PXIe-2727, is a versatile PXI Programmable Resistor Module featuring nine input channels with 16-bit resolution. This module is engineered to simulate resistance-based inputs and outputs, making it suitable for applications involving potentiometers, resistance temperature detectors (RTDs), voltage dividers, and bridge elements. The module utilizes an array of relays to programmatically adjust the resistance across each channel, which is particularly beneficial for hardware-in-the-loop (HIL) validation scenarios simulating various environmental conditions.

With an intuitive software interface, users can input values in either temperature or resistance units, allowing for precise resistance configuration on each channel. The accuracy of the module varies with resistance settings, achieving less than 5.0% accuracy for ranges between 20 Ω and 64 Ω, and improving to less than 2.0% for ranges between 64 Ω and 255 Ω. For settings between 20 Ω and 40 Ω, the accuracy is specified as less than 10.0%, while it is less than 5.0% for 40 Ω to 120 Ω, less than 2.0% for 120 Ω to 400 Ω, and less than 1.0% for settings between 400 Ω and 16,000 Ω. Notably, channel accuracy is influenced by total resistor accuracy, relay and trace path resistance, as well as temperature effects.

The module features a 37-pin D-SUB connector on the front panel, ensuring robust interfacing with external devices. Additionally, it comes equipped with a 2 × 2 Micro-Fit connector for digital multimeter (DMM) applications, enabling secure and efficient connectivity. The power specifications include an operational input requirement of 1.2 W at 3.3 V and a maximum draw of 11 W at 12 V, thereby supporting a range of power supply configurations to ensure optimal performance under various operational scenarios.