---
title: "Total energy in Chart’nX: add and subtract meters"
description: Calculate the total energy consumed in a Chart’nX dashboard by adding or subtracting input meters, sub-meters and groups, without double counting.
canonical: https://wiki.can-nx.com/en/guides/chart-operations/
language: en
product: Chart’nX
audience:
  - administrateur
  - installateur
context: "Chart’nX energy generator: General meters - Total energy consumed card, Operations protocol"
---

# Total energy in Chart’nX: add and subtract meters

Context: Chart’nX energy generator: General meters - Total energy consumed card, Operations protocol

In the Chart’nX energy generator, the **General meters - Total energy consumed** card can be calculated from other meters instead of being read from a meter. With the **Operations** protocol, you compose the sum or difference of input meters, sub-meters and groups, for example for a grid, photovoltaic and battery energy balance.

This configuration is intended for administrators and installers.

## Before you start

- The meters or [groups](https://wiki.can-nx.com/en/guides/chart-groups/) to use are configured.
- You know how these meters relate to each other, to avoid double counting.

## Choose a calculation by operations

1. In **Main meters**, open the **General meters - Total energy consumed** card and enable it.
2. In **Protocol**, choose **Operations**.
3. Click **+ Add operations**. The **Compose the calculation** window shows **Input meters**, **Sub-meters** and **Groups**, depending on what exists in the dashboard.

The total meter itself and the apparent power meter are not among the components of this energy calculation.

## Select the meters and their sign

1. Check the meters you want and choose **Sum** or **Subtract** on each selected row.
2. **Search for a meter…** filters by name, address or protocol. In each section, **Select all** or **Deselect all** applies to the eligible rows visible with this filter.
3. Clear the search before rereading the complete composition: choices hidden by the filter are kept.
4. Check the signs. The help states that the grid (purchase positive, sale negative) and the battery (discharge positive, charge negative) are already signed for the balance described. Do not subtract them because of their name alone: have the actual direction of their measurements confirmed if necessary.

The **Energy balance** shortcut selects the eligible input meters, **Sub-meters** the eligible sub-meters. They replace the eligible selection, choose **Sum** and clear the search. An old component that has become unavailable stays in place: remove it yourself if necessary.

## Save the composition

1. Click **Save**.
2. If a double-counting warning appears, reread the composition. It flags the same energy counted twice: an input meter together with a sub-meter or a group, or a group together with one of its own members. Correct the selections or signs concerned; click **Confirm** only if this composition is intentional.
3. Back in the card, [save the dashboard](https://wiki.can-nx.com/en/guides/chart-save/).

**Cancel** in the window exits it without applying the new composition.

## Check the result

In the card, reread the list of operations and **Meter unit of measurement** before saving the dashboard. An empty composition blocks saving the dashboard.

## Troubleshooting

| Situation | Cause and action |
| --- | --- |
| Grayed-out row showing **disabled**, **computed — cannot be composed** or **deleted** | Computed totals cannot be used in cascade as components of this total. |
| **A meter in the composition is disabled or deleted. Re-enable it or remove it from the operations. Saving is blocked.** | An old unavailable component stays visible so that you can decide to remove it or restore the appropriate meter. Do not replace it at random. |
| Shortcut showing **no eligible meter** | First check the meters and whether they are enabled. For a group, see [Configure groups](https://wiki.can-nx.com/en/guides/chart-groups/). |

If the intended calculation cannot be established unambiguously, or if saving fails after the corrections, contact support@can-nx.com, specifying the balance you are looking for, the meters concerned and the message, without sensitive data.