A18 Low Flow Cutoff

Definition

This function forces the flowmeter to display flow values below a set threshold as 0. The default value is 0, which disables the function.

When A18 Low Flow Cutoff is disabled, small near-zero measurement fluctuations may be displayed, causing slight value variations when the system is stopped.

To display a stable zero flow when the system is stopped, enable A18 to force flow values below the threshold to zero, preventing zero drift and minor measurement disturbances.

Notes

1. The default value is 0, which means the function is disabled and the flowmeter will display actual small flow values.

2. The condition “below the set value” is evaluated using the absolute value of the flow rate. Regardless of forward or reverse flow, any value lower than the set threshold will be displayed as 0.

3. A18 is a hard cutoff for both display and output. When the actual flow rate is lower than the A18 setting, the flowmeter will display 0 and no flow variation within this range will be output.

4. If the application requires measurement of small flow fluctuations near zero, the measured flow value must be greater than the A18 setting. Otherwise, the flow will be treated as 0 and cannot be measured or recorded.

5. Setting Recommendations

   • General process display / PLC false-trigger prevention: Set A18 close to the lower measurement limit of the flowmeter model to improve zero stability.

   • Low-flow detection / micro-flow research applications: It is recommended to disable A18 (A18 = 0) to preserve full measurement information near zero flow.

*Lower measurement limit

Pipe Size	DN15	DN20	DN25	DN32	DN40	DN50	DN65	DN75
Lower measurement limit	1.5 LPM	2 LPM	3 LPM	5 LPM	8 LPM	13 LPM	22 LPM	30 LPM

Operation Procedure

Button Functions (Click to Expand)

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

• Blue Button (leftmost): Return, exit, or save settings.

• Gray Direction Buttons:

  • Left Gray: Previous Page, decrease value, or select item

  • Right Gray: Next Page, increase value, or select item

• Orange Button (rightmost): Rightmost button: Enter settings, edit, or confirm selection

Do not hold buttons for extended periods to avoid damage.

Button functions may change depending on the operation context to improve usability or prevent accidental presses.

A18 Low flow cutoff Setting Steps
• From the main screen(green backlight), 
press Orange Button(Setup) to enter settings (orange backlight).
• Use Gray Arrow Buttons to select A. Measurement, press Orange Button(Enter).
• Use Gray Arrow Buttons to select A18 Low flow cutoff, 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).

A18 Options, RS485 Values, Read/Write Commands, and Formats

Input Range of This Parameter	Corresponding Values	RS-485 Value
Custom	0	-
Minumum	0	-
Maximum	150,000,000	-

Refer to the Read/Write Memory List for the Modbus command format. This parameter uses the float 32 data format.