Using my Kelvin micro-ohmeter which which I believe bypasses contact resistance in it's measurements, I measured a 16 gauge 312 cm wire (loopback) at .096 ohms (pretty close to what would be expected). Measuring with Limp as a loop back, it came to .51 ohms; presumptively due to contact resistance inclusion of .414 ohms. So, in setting the Cable Compensation Resistance in LIMP, I am wondering if I should include the contact resistance or not as contact resistance will exist in any design?
I have designed many systems with outcomes that I have been pretty pleased with but I never really thought about this before.
I have designed many systems with outcomes that I have been pretty pleased with but I never really thought about this before.
Thanks Allen.
Yes, the meter was zero'd before measurement, but since it measures with a 10 mAmp signal and then converts back to ohms using the Kelvin technique, I believe it bypasses the contact resistance in the alligator clips attached to the cable. I wonder about putting a short wire into the clip of the wire and see if that simulates the contact resistance. I realize that the difference is not likely to significantly impact the ultimate design, but it is fun to experiment. Thanks.
Yes, the meter was zero'd before measurement, but since it measures with a 10 mAmp signal and then converts back to ohms using the Kelvin technique, I believe it bypasses the contact resistance in the alligator clips attached to the cable. I wonder about putting a short wire into the clip of the wire and see if that simulates the contact resistance. I realize that the difference is not likely to significantly impact the ultimate design, but it is fun to experiment. Thanks.
There is still a point at which the measurement is accurate. Four-terminal sensing - Wikipedia
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