> 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/user-interface/user-interface-explanation.md).

# HMI Overview

### Main Unit Functions

The FU-ES features a dual-screen display:

* A **5-digit LED display** for high-contrast real-time data readout
* A **3-row, 3-color backlit LCD screen** for detailed data, page names, units, and button labels
  * Line 1: Current page name and units
  * Line 2: Actual measured data
  * Line 3: Available key functions for the current screen

<figure><img src="/files/tWichDsCCSJeZIThhgOO" alt=""><figcaption></figcaption></figure>

### **Button Functions**

The main unit has four buttons. The bottom line of the LCD, Line 3, shows the function of each button. The buttons are typically defined as follows:

<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="/files/bdd75120acea6361d128fd3deec06f1a8277e667" alt="" data-size="line"> **Blue Button (leftmost):** Return, exit, or save settings.
* Gray Direction Buttons:
  * <img src="/files/2e37e572251371c6020ab6d9e11c1fcdd5ef0369" alt="" data-size="line"> **Left Gray:** Previous Page, decrease value, or select item
  * <img src="/files/50a67ff5744401e217d5b9e838da3f7909be732f" alt="" data-size="line"> **Right Gray:** Next Page, increase value, or select item
* <img src="/files/uJJ6BEZ4sukIlwQaHrUB" 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>

<figure><img src="/files/FZpRrCZya8VI9SmdVEQB" alt=""><figcaption></figcaption></figure>

### **LCD Three-Color Backlight Function**

<figure><img src="/files/KlXbpuAX2snGp2Qv76lB" alt=""><figcaption></figcaption></figure>

The system provides a three-color backlight display. The **red backlight** only activates when the alarm setting is **“On”**. If the setting is **“DND (Do Not Disturb)”** or **“Off”**, the backlight remains off. The meanings of each color are as follows:

{% stepper %}
{% step %}

### **Green Backlight**

* System operating normally
* Displaying real-time information
* All data within normal range
  {% endstep %}

{% step %}

### **Flashing Red Backlight**

* Major abnormality (**Alarm A**) detected
* Refer to [**Alarms and System Status**](/qr/fu-es-echosense-instruction-manual/user-interface/alarms-and-system-status.md) for more information
  {% endstep %}

{% step %}

### **Red Backlight**

* **Alarm B:** User-defined alert condition triggered
* **Alarm C:** Maintenance reminder condition reached
* Refer to [**Alarms and System Status**](/qr/fu-es-echosense-instruction-manual/user-interface/alarms-and-system-status.md) for more information
  {% endstep %}

{% step %}

### **Orange Backlight**

* System operating normally
* Display is currently on the **Settings page**, not a real-time information screen
  {% endstep %}
  {% endstepper %}

{% hint style="info" %}

#### **DND (Do Not Disturb) Mode**

* System detects abnormalities, but **red backlight remains off**.
* Example: **Alarm-A “4 Off Pipe”** triggers no backlight.
* Abnormalities still appear on the **Abnormalities page**.
* **RS485** connection still sends alarm signals.
* **OCT output** continues to signal alarms if configured.
  {% endhint %}

***

## **Frequency of data update**

Because real-time flow data updates frequently, the LED screen updates before the LCD screen. The difference between the two displays may be about 0.1 seconds. If the value has only a few digits, use the LED screen as the primary reference.

## **Displayed digits on LED screen**

The LED screen displays up to five digits. If the value exceeds five digits, **FFFFF** appears on the LED screen, as shown below. To read the complete value, change the units or check the second row of the LCD screen.

<figure><img src="/files/JygPoNuuH8yxrZ96epbe" alt=""><figcaption></figcaption></figure>

**When flow is reversed and the value is negative, the first digit is a minus sign and the remaining four positions show the value.**


---

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