FDT-25W Wall Mounter Ultrasonic Flowmeter
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Generally the default value is 0.03m/s
The low-cutoff value does not affect the flow measurement when the actual flow is absolutely greater
than the low-cutoff value.
4.11 How to setup a zero point
There exists a ‘Zero Point’ with certain installation which means the flow meter will display a non-zero
value when the flow is absolutely stopped. In this case, setting a zero point with the function in window
M42 will bring a more accurate measurement result.
Make sure that there is no liquid running inside the pipe, and then run the function in window M42 by
pressing the ENT key.
4.12 How to get a scale factor for calibration
A scale factor is the ratio between the ‘actual flow rate’ and the indicated value by the flow meter.
It can be determined by calibration with standard flow calibration equipment. You may change the scale
factor in menu window M45.
The scale factor can be determined by calibration with flow calibration equipment.
4.13 How to use the system locker
The system locker provides a means of preventing inadvertent configuration changes or totalizer
resets.
When the system is locked, menu window browsing can be done without affecting any change, but any
modifications are prohibited.
The system can be locked without a password or with a 1 to 4 digit password. With a no-password
locking, directly press the ENT key in M47
If the password is forgotten, please contact the factory.
4.14 How to use 4-20mA current loop output
The accuracy of the current loop output is better than 0.1%. It can be configured to different mode,
such as 4-20mA mode, 0-20mA etc. Mode selection can be made in menu M55. Refer to the next
chapter for details on M55.
In order to use the 4-20mA output function, you need not only select the mode to be 4-20mA in
M55, but also set the flow rate values which correspond to the minimum current (4mA) and the
maximum current (20mA). Enter the two values in M56 and M57.