How Do I Select Configurations and Resistances of Strain Gauges in My FPGA VI for an NI 9237? Hardware: CompactRIO>>Analog Input Modules>>NI 9237
Problem: When using an NI 9237 module in an FPGA target, I don’t see a way to specify the resistance of my strain gauges or how to configure the module for quarter bridge measurement. Solution: The default configuration for the NI 9237 is full bridge. In full bridge, you must provide all four resistors (gauges) of the bridge externally. If you select half bridge, using a property node on the FPGA VI, the NI 9237 will provide half of the bridge internally leaving the other two resistors (gauges) for you to provide. To have a quarter bridge configuration, you must enable half bridge operation of the NI 9237 and wire a dummy gauge in addition to the strain gauge. At no point in configuring your NI 9237 do you need to specify the resistance of your gauges. Your selection of external gauge resistance will determine if you bridge is balanced. However, there is a 150mW power limit of the bridge. The resistance of your gauges will affect the power to the bridge. Please see the NI 9237 Operating Instructions for more information about power limitations and general configuration. Related Links: Product Manuals: NI 9237 Operating Instructions and Specifications Developer Zone Category: Measuring Strain with Strain Gauges Attachments:
Report Date: 11/08/2007 Last Updated: 02/12/2008 Document ID: 4F7B6L4H |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
