> For the complete documentation index, see [llms.txt](https://help.aranet.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.aranet.com/aranet-cloud-page/aranet-cloud-landing-page/user-interface-and-core-features/sensors/virtual-sensors/vapour-pressure-deficit-virtual-sensor.md).

# Vapour-Pressure Deficit Virtual Sensor

**Vapor-pressure deficit (VPD)** is one of the methods growers use to measure humidity in a greenhouse or growing environment. It allows growers to gauge the impact of humidity on plant growth and development.

VPD in Aranet Cloud is calculated according to the formula:

<div data-with-frame="true"><figure><img src="https://forum.aranet.com/site/assets/files/4310/ac_vpd_formula.png" alt=""><figcaption></figcaption></figure></div>

Required measurements:

<div data-with-frame="true"><img src="https://forum.aranet.com/site/assets/files/4310/ac_vpd_formula01.png" alt="" width="162"></div>

The default metric of VPD is *kPa.*

To create a virtual VPD sensor, navigate to the **SENSORS** menu -> **VIRTUAL SENSOR**S tab and press the **NEW VIRTUAL SENSOR** button:

<div data-with-frame="true"><figure><img src="https://2831658296-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FRKwQxnS51pLI9fOl4xXp%2Fuploads%2FnMq1AVNIAMjs7e2HYqEp%2Fimage.png?alt=media&amp;token=466c9576-6730-4754-b1a9-f58c8cfe0dc9" alt=""><figcaption></figcaption></figure></div>

Select Vapour-pressure deficit sensor:

<div data-with-frame="true"><figure><img src="https://2831658296-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FRKwQxnS51pLI9fOl4xXp%2Fuploads%2FpHQefPyq7Vlh6F4ouNo5%2Fimage.png?alt=media&amp;token=f8734553-9a98-4465-b38b-5ff882a1ebb2" alt=""><figcaption></figcaption></figure></div>

Give the sensor a name, select the source sensors, and press the **CREATE** button:

<div data-with-frame="true"><figure><img src="https://2831658296-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FRKwQxnS51pLI9fOl4xXp%2Fuploads%2FMUMsqRJ2iYSsqURxIOS6%2Fimage.png?alt=media&amp;token=a540d1bd-d5b5-4323-a078-0ceba07edc27" alt=""><figcaption></figcaption></figure></div>

Sensor is created:

<div data-with-frame="true"><figure><img src="https://2831658296-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FRKwQxnS51pLI9fOl4xXp%2Fuploads%2Fz7LZe5R5YBFUaBvL2ioc%2Fimage.png?alt=media&amp;token=1f4cedfd-1932-482a-9568-d9bb1ed4a11f" alt=""><figcaption></figcaption></figure></div>


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