Environmental compensation and measurement settings overview - HMT370EX

HMT370EX User Guide

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User guide

Pressure compensation

You can configure a pressure compensation value to HMT370EX using either the local display interface or Vaisala Insight PC software.
CAUTION You must enter the pressure compensation value in order to accurately measure calculated parameters that require pressure data. By default, the pressure compensation value is set as 1013.25 hPa.

Filtering factor

If the measuring environment produces occasional exceptionally high or low readings that need to be averaged out in the output, you can apply a filtering factor to the measurement output. The filtering factor defines the speed at which the latest measurement is integrated into the transmitter's output. For example, setting the filtering factor to 0.500 means that the displayed output is a 50%+50% combination of the previous measurement and the most recent measurement. To show the latest measurement directly in the output, set the filtering factor to 1.000 (no filtering).

HMT370EX has 2 alternative filtering factor options: either a default filtering factor that uses a 13 second moving average (T90), or a custom filtering factor defined by the user.

The filtering factor can be configured using the local display interface or Vaisala Insight PC software.

Calculation coefficients

When required, you can define the molar mass of the ambient gas (default value: 28.965 g/mol) and oil-specific calculation coefficients. The oil-specific calculation coefficients (selections Oil A and Oil B) are applicable only for the HMP378F oil probe model.
CAUTION The molar mass of the ambient gas must be defined when calculating gas dependent humidity parameters.
Note that calculation coefficients (molar mass of the ambient gas and oil-specific calculation coefficients) can only be entered with Vaisala Insight PC software.

For more information on the oil calculation coefficients for HMP378F, see HMP378F calculation model with average oil coefficients and HMP378F calculation model with oil-specific coefficients.