# D07 Hysteresis%

### Definition

Set the hysteresis percentage for clearing flow upper and lower limit alarms. This ensures the alarm is only cleared when the flow stabilizes back within the set range. The percentage is defined relative to the span between the upper and lower limits. Default: 03 (3%).

(D04 , D05 , D06 , and D07 work together to enable the flow range over-limit alarm function.)

<details>

<summary><strong>Flow Range Limit Alarm Example</strong> <em>(Click to Expand)</em></summary>

```
D05 Upper Limit: 30 LPM
D06 Lower Limit: 10 LPM
D07 Hysteresis: 3% (default)

Calculations:
Range: 30 − 10 = 20 LPM
Hysteresis: 20 × 3% = 0.6 LPM

Alarm Behavior:
When flow exceeds the upper limit (30 LPM), the alarm is triggered.
The alarm will clear only when the flow drops below 29.4 LPM (30 − 0.6).
When flow falls below the lower limit (10 LPM), the alarm is triggered.
The alarm will clear only when the flow rises above 10.6 LPM (10 + 0.6).
```

</details>

### Notes

This parameter must be a positive value.

{% hint style="info" %}

### DND Mode

When **Do Not Disturb (DND) mode** is enabled:

* The flow meter detects abnormal conditions but the red backlight will not turn on.\
  \&#xNAN;*Example:* Alarm-A “Paddle wheel abnormality” will not trigger the backlight in DND mode.
* Abnormal conditions are still displayed on the **Status/Alarm page**.
* If connected via RS485, the monitoring system still receives the alarm signal.
* OCT alarm outputs continue to operate if configured.
  {% endhint %}

### 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 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 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>

<details>

<summary>Flow Range Over-Limit Alarm Operation <em>(Click to Expand)</em></summary>

> When the flow range alarm is enabled and the flow reaches the alarm condition, **Alarm B** is triggered. Alarm bits (**Bit0, Bit1**) display **1** to indicate the alarm has been activated.
>
> The system responds according to the alarm mode set in **D04**:
>
> * **On**: The receiving device receives the alarm signal, and the flow meter screen displays a red backlight warning.
> * **Do Not Disturb (DND)**: The receiving device still receives the alarm signal, but the screen does not display the red backlight.

Set D04 to enable the flow range over-limit alarmD04 FlowLIM Alarm Setting Steps• From the main screen (green backlight), press Orange Button (Setup) to enter settings (orange backlight).• Use Gray Arrow Buttons to select D.Alarm & Info , press Orange Button (Enter).• Use Gray Arrow Buttons to select D04 FlowLIM Ala, press Orange Button (Enter).• Use Gray Arrow Buttons to choose the options. • Press Orange Button (Set) to confirm.• Press Blue Button (ESC) to return to the main screen (green backlight).Set D05 to define the flow upper limitD05 Up LIM Setting Steps• From the main screen(green backlight),   press Orange Button(Setup) to enter settings (orange backlight).• Use Gray Arrow Buttons to select D. Alarm & Info, press Orange Button(Enter).• Use Gray Arrow Buttons to select D05 Up LIM, press Orange Button(Enter).• Use Gray Arrow Buttons to choose the digit to adjust(highlighted in dark gray).• Press Orange Button(Edit) to enter adjustment mode.• Adjust digits: Left Gray Button to increase, Right Gray Button to decrease.• Press Orange Button(Set) to confirm each digit; repeat for other digits as needed.• After all digits are set, press Blue Button(Save).• Confirm by pressing Orange Button(Save) (or Blue Button(NOT) to cancel).• Press Blue Button(ESC) to return to the main screen(green backlight).Set D06 to define the flow lower limitD06 Low LIM Setting Steps• From the main screen(green backlight),   press Orange Button(Setup) to enter settings (orange backlight).• Use Gray Arrow Buttons to select D. Alarm & Info, press Orange Button(Enter).• Use Gray Arrow Buttons to select D06 Low LIM, press Orange Button(Enter).• Use Gray Arrow Buttons to choose the digit to adjust(highlighted in dark gray).• Press Orange Button(Edit) to enter adjustment mode.• Adjust digits: Left Gray Button to increase, Right Gray Button to decrease.• Press Orange Button(Set) to confirm each digit; repeat for other digits as needed.• After all digits are set, press Blue Button(Save).• Confirm by pressing Orange Button(Save) (or Blue Button(NOT) to cancel).• Press Blue Button(ESC) to return to the main screen(green backlight).Set D07 to define the flow hysteresisD07 Hysteresis Setting Steps• From the main screen (green backlight),   press Orange Button (Setup) to enter settings (orange backlight).• Use Gray Arrow Buttons to select D. Alarm & Info  , press Orange Button (Enter).• Use Gray Arrow Buttons to select D07 Hysteresis, press Orange Button (Enter).• Use the Gray Arrow Buttons to adjust the flow hysteresis percentage:• Press the Left Gray Buttons to increase the value• Press the Right Gray Buttons to decrease the value• Press Orange Button (Set) to confirm.• Press Blue Button (ESC) to return to the main screen (green backlight).Flow Range Over-Limit Alarm OperationWhen the flow range alarm is enabled and the flow reaches the alarm condition, Alarm B is triggered. Alarm bits (Bit0, Bit1) display 1 to indicate the alarm has been activated.The system responds according to the alarm mode set in D05:On: The receiving device receives the alarm signal, and the flow meter screen displays a red backlight warning.Do Not Disturb (DND): The receiving device still receives the alarm signal, but the screen does not display the red backlight.

</details>

### D07 Options, RS485 Values, Read/Write Commands, and Formats

| Parameter Input Range | Corresponding Values | RS-485 Value |
| --------------------- | -------------------- | ------------ |
| Default               | 03                   | 3%           |
| Minimum               | 00                   | 0%           |
| Maximum               | 10                   | 10%          |


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