> 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-tx320-english-v1/parameters/a-measurement-setup/a01-dn-pipe-choose.md).

# A01 DN Pipe Choose

Selects the nominal pipe diameter (DN) of the pipe being measured. A01 is the first step of pipe setup: the DN chosen here determines which pipe specifications appear in [A02 (Preset Pipe Spec)](/qr/fu-tx320-english-v1/parameters/a-measurement-setup/a02-preset-pipe-spec.md). Default: **DN 65 (2½")**.

### Notes

* Set A01 before A02. Changing A01 resets the A02 selection, because each DN has its own list of available specifications.
* If the pipe's actual dimensions don't match any listed specification, set A02 to **custom** and enter A04 (outer diameter) and A06 (wall thickness) manually.
* After changing the pipe setup, re-run [Z03 Auto Initialization](/qr/fu-tx320-english-v1/parameters/z-easy-setup/z03-auto-initialize.md) and Z04 Auto Zero Offset.

### Operation Procedure

<details>

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

When the main screen is displayed in **green backlight**, the four buttons function as follows:

* <img src="https://content.gitbook.com/content/fX3l9RzQpCUpspFteU5B/blobs/ya5mjywEtI16s3njJOBl/image" alt="" data-size="line"> **Blue Button (leftmost):** Return, exit, or save settings.
* Gray Direction Buttons:
  * <img src="https://content.gitbook.com/content/fX3l9RzQpCUpspFteU5B/blobs/0uWDDSFxxM6CfKg9agyl/image" alt="" data-size="line"> **Left Gray:** Previous Page, decrease value, or select item
  * <img src="https://content.gitbook.com/content/fX3l9RzQpCUpspFteU5B/blobs/MPA7mtqj4g7MXG4MSKfd/image" alt="" data-size="line"> **Right Gray:** Next Page, increase value, or select item
* <img src="https://content.gitbook.com/content/fX3l9RzQpCUpspFteU5B/blobs/tN3ntfY5TFvvlg0tCaZg/button-orange.png" alt="" data-size="line"> **Orange Button (rightmost):** 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>

```
A01 DN Pipe Choose Steps
• From the main screen (green backlight),
press Orange Button (Setup) to enter settings (orange backlight).
• Use Gray Arrow Buttons to select A. Measure, press Orange Button (Enter).
• Use Gray Arrow Buttons to select A01 Auto Pipe Spec, press Orange Button (Enter).
• Press Right Gray Button to start Auto Pipe Spec.
• Press Blue Button (ESC) to return to the main screen (green backlight).
```

<figure><img src="https://2757023840-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FfX3l9RzQpCUpspFteU5B%2Fuploads%2F2VQmbIoJd7TeSMzYwrSe%2FFU-TX320-A01-en.png?alt=media&amp;token=c5a4c0aa-4834-4beb-870b-695bd3406db1" alt="" width="394"><figcaption></figcaption></figure>

### A01 Selectable Diameters

| Nominal diameter    | Nominal size |
| ------------------- | ------------ |
| DN 15               | ½"           |
| DN 20               | ¾"           |
| DN 25               | 1"           |
| DN 32               | 1¼"          |
| DN 40               | 1½"          |
| DN 50               | 2"           |
| **DN 65 (Default)** | 2½"          |
| DN 75               | 3"           |
| DN 100              | 4"           |
| DN 125              | 5"           |
| DN 150              | 6"           |
| DN 200              | 8"           |
| DN 250              | 10"          |
| DN 300              | 12"          |
| DN 350              | 14"          |
| DN 400              | 16"          |
| DN 450              | 18"          |
| DN 500              | 20"          |
| DN 600              | 24"          |

> ⓘ A01 cannot be accessed via Modbus read/write commands in the current version. To read the configured pipe setup over RS485, read [A02 (specification)](/qr/fu-tx320-english-v1/parameters/a-measurement-setup/a02-preset-pipe-spec.md), [A04 (outer diameter)](/qr/fu-tx320-english-v1/parameters/a-measurement-setup/a04-pipe-outer-diameter.md), [A06 (wall thickness)](/qr/fu-tx320-english-v1/parameters/a-measurement-setup/a06-pipe-thickness.md) and [A07 (inner diameter)](/qr/fu-tx320-english-v1/parameters/a-measurement-setup/a07-pipe-inner-diameter.md).


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