> For the complete documentation index, see [llms.txt](https://docs.lorric.com/qr/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.lorric.com/qr/fu-lt-english-v1/parameters/z-easy-setup/z04-automatic-zero-offset.md).

# Z04 Automatic Zero Offset

### Definition

This function recalibrates the flow meter zero point (0 flow) by resetting the output to zero.\
For ultra-low flow measurements, zero calibration helps correct zero-offset errors and improves accuracy.

The function starts after pressing **Start** and automatically updates **A22 (Auto Zero Offset)** upon completion.

**Recommendation**\
It is strongly recommended to execute **Z04** when measuring flow rates below **10% of full scale**, as small zero offsets can cause significant errors at low flow.

**Example**

* Zero offset: **0.2 L/min**
  * Actual flow **100 L/min** → error ≈ **0.2%**
  * Actual flow **0.5 L/min** → error ≈ **40%**

{% hint style="info" %}
Parameter Z is not supported for Modbus read/write operations in the current version.
{% endhint %}

### Notes

1. Perform Z04  when the pipeline is <mark style="color:red;">**fully filled with liquid and the liquid is completely stationary**</mark><mark style="color:red;">.</mark> Performing Z04 when the pipe is not full may cause flow measurement errors and unstable readings; if this occurs, repeat Z04 under full-pipe conditions.
2. <mark style="color:red;">**Repeat this procedure after every reinstallation or when changing pipe size or material.**</mark>
3. The **Z04** function is equivalent to **A22**; users can choose either.\
   (Z-series parameters are designed for quick setup, consolidating multiple essential settings to streamline installation.)

### Operation Procedure

<details>

<summary><strong>Button Functions</strong> <em>(Click to Expand)</em></summary>

The main unit has **four buttons**. The **bottom line (Line 3)** of the LCD displays the current function of each button. Under normal operation, the button functions are as follows:

* <img src="/files/bdd75120acea6361d128fd3deec06f1a8277e667" alt="" data-size="line"> **Blue Button -** Leftmost button: Return, exit, or save settings.

Gray Arrow Buttons:

* <img src="/files/2e37e572251371c6020ab6d9e11c1fcdd5ef0369" alt="" data-size="line"> **Left Gray Button:** Previous Page, decrease value, or select item
* <img src="/files/50a67ff5744401e217d5b9e838da3f7909be732f" alt="" data-size="line"> **Right Gray Button:** Next Page, increase value, or select item
* <img src="/files/6c0b22a2048cf9b2afd86fac7a65e414feb967d4" alt="" data-size="line"> **Orange Button:** Rightmost button: Enter settings, edit, or confirm selection

{% hint style="danger" %}
**Do not hold buttons for extended periods to avoid damage.**
{% endhint %}

{% hint style="info" %}
Button functions may change depending on the operation context to improve usability or prevent accidental presses.
{% endhint %}

</details>

{% code fullWidth="false" %}

```
Z04 Automatic Zero Offset Setting Steps
• From the main screen (green backlight), 
press Orange Button (Setup) to enter settings (orange backlight).
• Use Gray Arrow Buttons to select  Z. Easy Setup , press Orange Button (Enter).
• Use Right Gray Arrow Buttons to start Automatic Zero Offset
• Device shows “Start auto Z04” when automatic zero-flow begins.
• After ~30 seconds, it displays “Set zero offset to ____”.
• Then it returns to Z04 Auto Zero Offset, indicating completion.
```

{% endcode %}

<figure><img src="/files/aGZNAUtVwatARukwGKe7" alt="" width="375"><figcaption></figcaption></figure>


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.lorric.com/qr/fu-lt-english-v1/parameters/z-easy-setup/z04-automatic-zero-offset.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.