Verifying Calibration; Zero Offset; Scale Factor - Micromeritics 1305 Operator's Manual

Model 1305 MultiVolume Pycnometer
Specific volume is defined as the volume per unit weight and is computed as
where
U
SAMP

Verifying Calibration

Two quick checks may be made to determine if the instrument needs to be recali-
brated.
•
the zero offset or additive errors of the instrument
•
the scale factor errors (assuming that the zero offset errors are negligible)
These checks should be made if changes have occurred in the inner parts of the
instrument, the sample chamber or cap, the sample inserts, the sample cups, or if
the temperature differs appreciably from the temperature at the time of the pre-
vious calibration.

Zero Offset

Verify the zero offset by running the empty sample cup and calculating the re-
sult. The error from zero should be less than 0.2% of the full scale range.

Scale Factor

Verify the scale factor by placing the calibration volumes (balls) in the sample
cup and running them as if they were samples and computing the results. The vol-
ume error from the values supplied on the calibration data sheet should be less
than 0.2% of the full scale range. The calibration data sheet and the calibrated
volumes are supplied in the accessory package and are designated as V
numerical suffixes to indicate the range.
If excessive errors are revealed during verification, perform the calibration proce-
dure in the following section to establish new, accurate values for the V
V instrument constants.
EXP
Jun 99
V
SAMP
= =
U
SAMP ρ
W
SAMP
SAMP
= sample specific volume.
1
Verifying Calibration
with
CALIB
and
CELL
3-15