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Zero Calibration Using the Main Menu:
In the main menu, select “damping/cutOff/Zero” -> “Zero
calibration”
•
Stop flow of fluid (close a valve)
•
Choose Set Zero
Deleting the zero value
In the main menu
, select “Zero Setup” - “Zero” - “Delete
zero”. This action deletes the zero calibration and resets
the meter to factory settings.
Once the zero offset has been set, it will remain in
the system until it is deleted or a new zero offset
has been set. We recommend to make new zero
setting at each new measurement when possible.
CAUTION
i
In the course of zero calibration with closed
pipe valves, the UFM calculates the transit-time
differential that may develop between the trans-
ducers and any residual flow. This calculated
time (including zero) is automatically included for subse
-
quent calculations during flow measurement. This method
enhances the precision of the flow measurements. If it is
not possible to close the pipe valves, delete the zero value
that may have been set previously. If anything prevents
performing a zero calibration, take the corresponding
imperfection into account in your measurements. The
zero setpoint is retained in device memory until it is
overwritten with a new zero setpoint. If it was possible
to close the pipe valves, check the “Flow” column in one
of the three measuring windows to determine whether
or not the flowrate is going down. Do not perform a zero
calibration until a settled value is output to the flow display.
A stop valve is not available at all positions of the piping.
The tolerances that develop during installation, including
tolerances of the ultrasonic transducers and pipe data,
will lead to a certain zero offset error in the measuring
equipment. Provided care was taken during installation,
the flow velocity error should stay within the range from
0.00 ft./s to 0.09 ft./s. The zero offset error is reduced in
proportion with increasing pipe size.
ZERO SETTING
It is advisable to run a zero calibration before starting
measurements, if possible.
Prerequisite for error-free zero calibration is the
complete setup of the device, proper installation of
both ultrasonic transducers on the pipe, and their
electrical interconnection with the flow transmitter.
Zero-flow is required for error free calibration. Wait
two minutes after stopping process/shut-off pipe
to allow the flow to calm down.
CAUTION
Zero Calibration Starting in “Flow 1” Menu
1. Close the valves of the piping.
2. Navigate to the “Setup” window as follows, using one
of three options:
3. After power-on: Select “Setup” within the start se
-
quence
4. In the primary measuring window “Flow 1”: Select
“Setup” and “Zero Setup”
5. Select “Set Zero”
The following window opens on completion of zero
calibration:
The UFM displays the calculated correction value for
the signal transit-time on completion of zero calibration.