Can I Use Remote Sense with the SCXI-1520 Configured for Quarter-Bridge Measurements?Hardware: SCC>>Modules
Problem: I am using the SCXI-1520 to perform quarter-bridge strain gage measurements. Since I have long leads connecting the strain gages to the SCXI-1520, I would like to use remote sense to eliminate error introduced by lead resistance. I have referred to Figure 2-8 of the SCXI-1520 User Manual and Specifications, which shows how to use remote sense with full-bridge measurements. However, it is unclear to me how this information applies to quarter-bride configurations. Is it possible to use remote sense using a quarter-bridge configuration, and if so, what connections do I need to make? Solution: You can use remote sense with a quarter-bridge configuration. To do this, simply connect the RS+ input of the SCXI-1520 to the P+ input. The RS- line is connected to P- internally through a 1 kOhm resistor. Because of this, you still need to compensate for the long wire length on the negative side of the bridge, which will show up in the measurement as an offset. National Instruments recommends you perform an offset nulling calibration on the bridge to get the most accurate readings. Related Links: KnowledgeBase 399FFBMV: Remote Sense Inputs on the SCXI-1520 and PXI-4220 Product Manuals: SCXI-1520 User Manual and Specifications (September 2005) Products and Services: NI SCXI-1520 Attachments:
Report Date: 02/28/2008 Last Updated: 12/17/2008 Document ID: 4IRDEL9S |
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