The HMP378F probe option is a variant of the standard HMP378, designed for measurements in oil. The mechanics of the probe are the same as in the standard HMP378 probe option (see HMP378 probe for pressurized pipelines).
The default HMP378F calculation coefficients (see HMP378F calculation model with average oil coefficients) are valid for transformer oil. Typically, moisture in transformer oil measurement with HMP378F has a ppm accuracy of ±10 % of the reading. If required, different oil-specific calculation coefficients can be configured into use to customize HMP378F measurements. For instructions, see Configuring calculation coefficients.
HMP378F uses the HUMICAP® 180L2 sensor designed specifically for oil and fuel measurements. For HUMICAP 180L2 sensor specifications, see HMP378F calculation model with average oil coefficients.
The following measurement parameters are available for HMP378F:
| Parameter | Abbreviation | Unit |
|---|---|---|
| Temperature | T | °C (°F) |
| Relative saturation | RS | %RS |
| Water activity | aw | - |
| Water concentration in oil 1 | H2O (oil) | ppmw |