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TTI-22 Iss.04– 11/15
After this selection TTI-22 automatically goes back into measuring mode.
1 Resistance
Display of ohmic resistance with four digits after the decimal point.
2 Temperature
Display of temperature with three digits after the decimal point.
3 Resistance Stat.
Display of resistance statistics: Display of current resistance, mean value and standard deviation of N
previous values.
We recommend this display type for high-precision resistance measurements.
•
Use the arrow keys to set the number N, the amount of values used for averaging, between 5 and 50.
•
After each change to the number N it takes N x 1.44 seconds until a new statistic is displayed (see
Fig. 7 - 8).
Fig. 7 - 8
Display of resistance statistic
The mean value and standard deviation are calculated using the following formulas:
Calculation of Mean:
N
i
i
Mean
R
x
N
R
Mean
1
1
Calculation of empirical standard deviation S. Dev.:
N
i
Mean
i
R
R
x
N
Dev
S
1
2
)
(
1
1
.
.
The standard deviation is a measure of the short-term stability of the measuring values and should be lower
than the expected measuring uncertainty.
4 Temperature Stat.
Display of temperature statistics: The current temperature is displayed with four digits after the decimal
point; the mean value and the standard deviation are displayed with five.
