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Hi



I am a newbie here, kindly bear with me if anything odd.



My company recently acquired a Chinese viscometer model NDJ-8S. There are many manufacturers in China making this model with different appearance. None of them have proper Operation Manual, just only crude translation of some Chinese manual.

I tried to get test a few sample Newtonain liquids, under same environment conditions:

1) Rotor #3, 60RPM
Sample AA read 1819 cps @78.4%
Sample BB read 1622 cps @69.9%
Sample CC read 1070 cps @46.1%

2) Rotor #4, 30RPM
Sample DD read 3366 cps @16.0%
Sample EE read 2703 cps @12.9%

3) Rotor #4, 60RPM
Sample EE read 2287 cps @21.8%
Sample FF read 1727 cps @16.4%
Sample GG read 4803 cps @45.8%

I am confused because the % is also varying with the viscosity for each sample. How do I know what is the exact Viscosity of a sample (at least to ±3% accuracy as mentioned in specs)?