Products > Test Equipment
Some old school instruments showing how it's done (HP 3325A and Fluke 8506a)
joeqsmith:
Yes, that's the heating system running. It's gas.
SilverSolder:
There does appear to be some correlation between the temperature swings and the readings, but there are other factors in there too...
joeqsmith:
I'll scale the data next time to give you a better idea what things look like. It's been running for around 13 hours.
The meter only resolves to 4 places beyond the decimal. In the 100 ohm range, meter is good for +/-(0.002% of reading + 1.4 counts(5.5 place)).
Worse case, resistor tolerance + meters error = 0.00434ohms. So I am expecting it to read between 60.00434 to 59.99566 ohms.
If we assume our temperature stays within 3degC. Vishay K part has 1ppm tempco and will only change 0.00018. The meter has a tempco of 0.0007 +0.2 counts per deg. C. = 0.00042 + 0.00002 or 0.00132 ohms. Adding the resistor, 0.0015 ohms, almost all of it being the meter. House may shift a little more than this but I think that 1.5mohm is about what we are looking for.
Then again, don't rule out the lack of coffee.
SilverSolder:
I like the "bell curve" graph, with the count of measured values - that pretty much tells you what you can expect. And it looks nicely Gaussian, with no missing values!
joeqsmith:
After 20 hours of runtime, with the meter zero'ed, the readings are from 60.0004 to 59.9985. Accuracy and drift seem about what I would expect.
Second plot is looking at the last hour and a half or so of data.
I have attached the data which is ASCII. The first column is the resistance, the second, temperature.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version