Products > Test Equipment

Some old school instruments showing how it's done (HP 3325A and Fluke 8506a)

<< < (56/91) > >>

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

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod