From the Sept/Oct 2010 tests, I found that new, sensor-specific, calibrations of E.lambda and Tau63_ref from the agar test produced results with less scatter. Thus, the plan is to use these for data processing. Since I will need to rely on these values, it seems like a good idea to do agar post-cals on these probes. In addition, I might as well double-check the probe resistances, so Chris is now making a test cable that I'll use with the HP5006 plug-in 4-wire meter. With these revised calibrations, I'll go back and look at the PCAPS data when the soil wasn't frozen. Finally, we'll rerun some tests in the FLAB yard. I'm not planning a new set of keg tests.
Resistance values measured 15 Apr 2011 using 4-wire meter:
ID |
Sensor S/N |
R_measured |
R_manufacturer |
|---|---|---|---|
1 |
200589 |
16.14 |
16.1 |
2 |
200590 |
15.40 |
15.4 |
3 |
200236 |
14.79 |
14.8 |
4 |
200591 |
16.70 |
16.7 |
5 |
200239 |
16.37 |
16.2 |
6 |
200592 |
15.53 |
15.5 |
7 |
200241 |
16.27 |
16.2 |
8 |
200242 |
16.10 |
15.9 |
9 |
200243 |
15.76 |
15.6 |
10 |
200234 |
14.72 |
14.7 |
11 |
200238 |
|
15.4 |
|
200235 |
|
14.8 |
|
200240 |
lightning fried |
15.0 |
All are within 0.2 ohms of manufacturer values. Except for one at 0.01 ohms, our values are higher. <Might> be connectors, but 4-wire measurement should compensate.