# Apply a depth-to-water calibration

> For the complete documentation index, see [llms.txt](https://docs.oriondata.io/llms.txt)

Apply a depth-to-water template to a soft sensor using matching reference measurements.

A DTW calibration converts level readings into a depth to water measurement. It is intended for users with super user access who are responsible for configuring sensor data transformations.

## Before you start

Make sure the following is true before you begin:

- You have super user access. This is required to create soft sensors and calibrations.
- You have already created the soft sensor that this calibration will be applied to. If you have not done this yet, see _Creating a soft sensor in Orion Data_. Soft sensors are created from the **Channels** tab.
- You have your reference measurements ready: the **Dip** and the **Head of water at time of dip**.

## Open the calibration page

1. Go to **Devices** and select the device that contains your soft sensor.
2. Click the **Calibration** tab.
3. From the **Select Sensor** dropdown, choose the soft sensor you created for the DTW measurement.

![Select Sensor dropdown open on the Calibration tab, with the Water Level soft sensor highlighted](https://docs.oriondata.io/images/portal/calibrations/examples/setting-up-a-depth-to-water-dtw-calibration/select-sensor-dropdown-open-calibration-tab-water-level-soft-sensor.png)

## Apply the DTW template

1. Click **Create From Template**.
2. In the search field, type DTW.
3. Select the DTW template from the results.

![Create From Template dropdown searched for DTW, with a DTW(m) Calc template highlighted](https://docs.oriondata.io/images/portal/calibrations/examples/setting-up-a-depth-to-water-dtw-calibration/create-from-template-dropdown-searched-dtw-dtw-m-calc-template.png)

## Enter the required values

The DTW template requires two reference values taken at the same point in time:

- **Dip** - the manually measured depth to water at the time of the reference reading.
- **Head of water at time of dip** - the corresponding sensor level reading captured at the same moment as the dip.

1. Enter the **Dip** value.
2. Enter the **Head of water at time of dip** value.
3. Click **Save**.

![DTW calibration steps with the Dip and Head of water at time of dip value fields highlighted](https://docs.oriondata.io/images/portal/calibrations/examples/setting-up-a-depth-to-water-dtw-calibration/dtw-calibration-steps-dip-head-water-time-dip-value-fields.png)![DTW calibration steps with an arrow to the Save button](https://docs.oriondata.io/images/portal/calibrations/examples/setting-up-a-depth-to-water-dtw-calibration/dtw-calibration-steps-save-button.png)

## Recalculate previous data

Saving the calibration applies it to new readings going forward. To apply the calibration to data already recorded against the sensor, run a force-recalculation.

For instructions, see _Using Force-recalculation_.

![Calibration Step Groups with the DTW(m) Calc group and the Force-recalculation button highlighted](https://docs.oriondata.io/images/portal/calibrations/examples/setting-up-a-depth-to-water-dtw-calibration/calibration-step-groups-dtw-m-calc-group-force-recalculation-button.png)

## Summary

This article covered how to apply a DTW calibration to an existing soft sensor in Orion Data. You opened the **Calibration** tab for the device, selected the soft sensor, applied the DTW template using **Create From Template**, entered the **Dip** and **Head of water at time of dip** values, and saved. Running a force-recalculation then applies the calibration to previously recorded data.

## Next Steps

- Verify the calibrated output by viewing the soft sensor’s recent readings.
- Run a force-recalculation to apply the calibration to historical data. See _Using Force-recalculation_.
- Configure alarms on the soft sensor if you need to be alerted to defined depth to water conditions.

## Related articles

- [Create a soft sensor](https://docs.oriondata.io/portal/getting-started/creating-a-soft-sensor/)
- [Recalculate historical sensor data](https://docs.oriondata.io/portal/calibrations/using-force-recalculation/)
- [Calibrations and sensor values](https://docs.oriondata.io/portal/calibrations/understanding-calibrations/)
- Setting up sensor alarms in Orion Data