SCXI 1520 for load measurement cable lengths of 500 meters

[grte]

HI ,

I ned to measure lod from a 1000 ohm full bridge circuit. The distance between the sensor & my SCXI 1520 is 500 meters. Please let me know how can I compensate for the lead resistances both in Excitation & while reading back the actual sensor value.

[AEI_JR]

grte,

For extremely long cable runs resulting in much higher than normal lead resistance to bridge resistance ratios, you must use remote sense, which is a six wire connection (four wires for excitation and two for signal).  Refer to your SCXI-1520 manual for more information:  http://www.ni.com/pdf/manuals/372583d.pdf, specifically page 2-9 and Chapter 4, Theory of Operation.

[grte]

Hi,

Thanks for your response. It would be of great help if you can show me a practical example. My leadresistance for a 100 meter cable will be around 8 ohms. PLease let me know the maximum cable length the SCXI 1520 can support.

Also please forward any cases where SCXI 1520 is being used for applications with cable lengths more than 300 meters.