The Micro-Measurements brand of Vishay Precision Group, Inc. introduced the MRF-Series Bridge Completion Modules (BCM). Built with Vishay foil resistors, the most stable resistor technology available, the MRF-Series improves the quality of strain measurements for a broad range of applications, such as medical, smart manufacturing, structural health monitoring (SHM), machine health monitoring (MHM), and human health monitoring (HHM).
Since many general-purpose instruments do not provide internal bridge completion capability, the MRF-Series of BCMs effectively implements a full Wheatstone bridge for accurate and stable measurements when testing specimens structured as a ¼ -bridge (single gage) or ½ -bridge (dual gages).
“The accuracy of the strain measurement depends on the quality of the strain gage used, but also on the bridge completion circuit attached to it. Installing it close to the strain gage and using Bulk Metal Foil resistors helps to optimize the measurement accuracy. Micro-Measurements offers a wide selection of qualified and dedicated BCM for strain gage sensors that cover the spectrum of values. The MRF-Series are specially fabricated using Bulk Metal Foil resistor technology to meet the highest performance standards under a wide range of environmental conditions. These MRF modules are designed to ensure reliable and repeatable accurate results,” said Ron Zuckerman, Sr. Manager of Sales & Marketing for Micro-Measurements Advanced Sensors.
The MRF-Series modules are offered in several configurations that will allow for bridge completion for 120, 350, 1000 and now 5000 ohm quarter-bridges along with half bridge completion as well.
The small size 1.3 x 0.7 x 0.2 inch (32 x 18.2 x 5.7 mm) allow for direct installations in tight areas such as medical devices and printed circuit assemblies. Additionally, at a weight of only 6 grams, the MRF-Series modules can be installed on rotating equipment such as drive shafts, draw-bridges, wind turbines, among other applications. The MRF-Series of BCMs provide other advantages including minimizing the number of solder connections required to complete the circuit and decoupling the bridge completion circuit from any strains present in the underlying surface.
MRF-Series Bridge Completion Modules employ Vishay foil resistors which provide an ultra-low temperature coefficient, low thermal EMF, fast response to current change, and/or low power coefficient of resistance. This results in a very low resistance temperature coefficient equivalent to ±0.15με/°F (±0.27με/°C) for the half-bridge circuits, and ±0.35με/°F (±0.63με/°C) for the dummy gages, over a temperature range from 0° to +200°F (–18° to +95°C). Maximum operating temperature range is –50° to +250°F (–45° to +120°C).
These versatile modules also enables a user to make ¼-bridge and ½-bridge inputs to instrumentation that may not have internal Wheatstone bridge completion built-in. They are especially useful when completing the Wheatstone bridge near the strain gage installation is possible.
Additional information about the MRF-Series Bridge Completion Modules and Micro-Measurements’ other solutions can be found at Micro-Measurements.