The PARIO device is not recognized by the software.
Check to ensure the device is shown in the device manager. If it is listed under “other devices,” please try to update the driver. If it is listed under “USB controller,” please contact METER support.
Is there an instruction video for PARIO?
Here's a link to the video: PARIO Plus-How to Make a Measurement: https://metergroup.wistia.com/medias/q89n8v3j6v
Do the PARIOs have to be sent to METER/Germany for calibration on a regular basis (recommended in the PARIO manual to send the devices for calibration verification every 2 years)?
The functionality of the PARIOs can be tested by running a measurement on air and in distilled water. A complete check of the calibration and a recalibration can only be made by sending the device to METER. It is not mandatory to send it in every two years if it still works correctly.
Do I have to consider the mass of dispersant in the calculation of the mass of particles?
It depends. When the dry soil weight is determined with a pretest sample, mass of dispersant does not have to be considered in evaluation. Furthermore, the software automatically corrects the pressure values, considering the different density.
Similarly, if the PARIO sample is wet-sieved after the PARIO measurement, the mass of dispersant does not have to be considered by determining the dry soil weights of the sieve residues as it should be washed out completely.
If, on the other hand, the dry soil weight is determined after PARIO measurement, the mass of dispersant has to be subtracted from the total dry soil mass.
What happens if I shake and measure the same sample multiple times?
Clay conglomerates dissolve amongst others because of mechanical abrasion of the particles, which consequently causes a slight increase in the clay fraction.
What is the upper limit of mass of material that can be used?
Software limit: 100 g
The more material you have in the cylinder, the more accurate the measurement is as you have an increasingly recognizable change in pressure. On the other hand, a disadvantage regarding Stokes’ law explains that more particles in the cylinder can influence each other during the sedimentation process. The amount of particle mass is also limited through the limited measuring range of the pressure sensor.
How do I fill the sedimentation cylinder correctly?
The surface of the suspension in the sedimentation cylinder forms a curved meniscus. The meniscus contacts the liter mark at the deepest point. Remove air bubbles by lightly knocking on the glass. Additionally, use a dropping pipette for precise filling of the cylinder.
What condition should the initial material have?
The initial material should be an air dry soil sample which is sieved to 2 mm.
What happens if the organic matter is not destroyed?
Organic matter works as a cementing substance and can lead to aggregation of the primary particles. This falsifies the sedimentation of the single particles.
What are the possible reasons for an increasing pressure curve at the beginning of the measurement?
Air bubbles in the suspension, which arise during shaking and rise up during measurement
Water drops which run down the border of the cylinder during measurement
Foam, arising from shaking and dissolving during measurement
What is the minimum pressure change necessary for a valid measurement?
A minimum pressure change of 10 Pa during the whole measurement time is valid.
Often the measured clay content rises with the number of repeat measurements of the same sample.
This effect may be a consequence of the shaking process before starting the measurement. The more often you shake the suspension, the more the dispersion increases, and the larger particles rub together and decrease in size.
The "Value [%]" column should specifiy the fraction of grains retained on the respective sieve. But what is the basis of the calculation?
The basis is the total dry soil weight of the total sample you weighed into the PARIO cylinder, including sand, silt and clay.
Sometimes the software does not recognize the start of the measurement when putting the sensor into the suspension.
This may happen if the tilt angle (approx. 45 °) is not big enough, or if the tilting is too tentative. Please refer to the following link for a quick video on the correct tilting of the sensor unit.
How is it calibrated? Is it calibrated annually? How can we assure that the pressure recording is correct?
PARIO is calibrated with a two-point pressure calibration using an accurate reference pressure sensor. A multi-stage temperature calibration (range 10 °C – 30 °C, 5 steps) is done in a climate chamber.
PARIO is calibrated once after manufacturing, not annually.
You can check the performance of the device by taking a measurement on air. The pressure should be about 0 Pa (+/- 5 Pa). In addition, you can measure in clear distilled water. The pressure should be at about 1800 Pa (+/- 5 Pa).
What should I do if soil particles stick on the cap or in the glass after mixing?
The particles that stick to the glass cylinder after shaking are the coarse sand particles (finer particles are carried with the water). The coarse sand particles are not part of the sedimentation analysis. The proportion of the sand fraction has to be determined by wet sieving of the material separately. This problem is common with a sedimentation experiment, including those conducted using a hydrometer or pipette method.