# Metric collection for Parameters

## Overview

**Metric collection** allows you to store historical information for Parameter values received from managed devices. When enabled, CONTROL automatically captures and stores data points over time, enabling trend analysis and historical reporting.

## Enabling Metric Collection

To activate metric collection for a Parameter:

1. Navigate to the [Parameter configuration screen](/books/control/page/parameter-configuration)
2. Enable the `metric` option

[![metric_enable.png](https://docs.zequenze.com/uploads/images/gallery/2026-02/rqwwdk69vygVtMf9-tmpyki51t0x.png)](https://docs.zequenze.com/uploads/images/gallery/2020-03/Wp89EzDvJnpxeXV9-metric_enable.png)

**Note:** Metric collection is primarily designed for Parameters that return numeric values. For non-numeric Parameters, see the [Non-numeric Parameter Metrics](#bkmrk-non-numeric-metrics) section below.

## Metric Types

CONTROL supports three types of metrics for Parameters: **Absolute** (default), **Counter**, and **Delta**. Each type determines how received values are processed and stored.

[![Screenshot-from-2020-03-30-15-49-08.png](https://docs.zequenze.com/uploads/images/gallery/2026-02/DjZ4WDXqq24fZ42j-tmpiq0vrkdo.png)](https://docs.zequenze.com/uploads/images/gallery/2020-03/ETmSgcU4Wl67QJxz-Screenshot-from-2020-03-30-15-49-08.png)

### Absolute Metrics

This metric type stores the exact value received from the device after applying:

- Unit conversions (when configured)
- [Processing scripts](https://docs.zequenze.com/books/control/page/processing-scripts-for-parameters) (when configured)

Use this type when you need to track the actual reported values over time (e.g., temperature, voltage, signal strength).

### Counter Metrics

This metric type stores the **rate of change** between consecutive values. The calculation is:

```
stored_value = (current_value - previous_value) / time_elapsed
```

The calculation is performed after applying:

- Unit conversions (when configured)
- [Processing scripts](https://docs.zequenze.com/books/control/page/processing-scripts-for-parameters) (when configured)

Use this type for continuously incrementing counters where you want to track the rate (e.g., bytes per second, requests per minute).

### Delta Metrics

This metric type stores the **difference** between consecutive values. The calculation is:

```
stored_value = current_value - previous_value
```

The calculation is performed after applying:

- Unit conversions (when configured)
- [Processing scripts](https://docs.zequenze.com/books/control/page/processing-scripts-for-parameters) (when configured)

Use this type when you need to track the absolute change between readings (e.g., change in disk usage, change in user count).

## Visualization of Parameter Metrics

TBC

<h2 id="bkmrk-non-numeric-metrics">Non-numeric Parameter Metrics</h2>

TBC