GF PF220 V2 Betriebsanleitung Seite 36

Operation of the device
Method 2: Manual intervention
To manually adjust the zero flow offset:
NOTICE
In order to cancel any applied offset you must either read flow via quick start or switch the flowmeter off & on. Any value that you
trim-out using the offset adjustment will be added/subtracted from the flow reading across the whole range.
8.3.3 Adjusting the calibration factor
NOTICE
USE THIS FACILITY WITH CARE & ONLY WHERE NECESSARY
The flowmeter is fully calibrated before leaving the factory and under normal circumstances does not require further calibration
when used on site.
This facility can be used to correct the flow indication where unavoidable errors occur due to the
lack of a straight pipe or where the sensors are forced to be fitted close to the pipe-end, valve,
junction etc.
Any adjustment must be made using a reference flowmeter fitted in the system.
With the system running:
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1. Stop the liquid flow.
2. With the instrument in FLOW READING mode, press the
Velocity function key and observe the reading (m/s). Any
reading other than 0.000 indicates an offset error and
in practice this will typically be in the range ±0.005m/s
(possibly higher with smaller diameter pipes). If a greater
figure is shown, it is worth calibrating the offset to obtain a
more accurate result. Continue as follows:
3. Press the ENTER key and select 'Yes' to confirm that you
want to exit the flow screen. The Main Menu is displayed.
4. Select View / Edit Site Data.
5. Use the UP/DOWN arrow keys to select Cutoff Velocity.
Press the ENTER key.
6. Edit the value as required and then press the ENTER key.
7. Scroll down to select Read flow using selected sensor and
press the ENTER key.
8. Check that the flowmeter is now reading zero correctly.
9. Restart the fluid flow.
1. Stop the flowmeter's totaliser and zero it (see section Total
flows).
2. Start the flowmeter reading flow. Use the flowmeter
totaliser to measure the total flow over a 30-60 minute
period, and note the total flow indicated by the reference
flow meter over the same period.
3. Calculate the % error between the flowmeter and
reference meters. If the error is greater than ±1% calibrate
the flowmeter as detailed below.
4. Press the ENTER key and select 'Yes' to confirm that
you want to exit the Read Flow screen. The Main Menu is
displayed.
Select View / Edit Site Data.
5.
6. Use the UP/DOWN arrow keys to select Calibration factor.
Press the ENTER key.
7. Change the calibration factor according to the error
calculated in step 3. For example, if the flowmeter was
reading 1% high, decrease the Calibration factor value by
approximate this amount. Since that start value is 1.00, the
calibration value should be 0.99. Conversely, if the reading
is 1% low then increase the calibration factor to 1.01.
8. Press the ENTER key to apply the change and return to the
View/Edit Site Data menu.
9. Scroll down to select Read flow using selected sensor and
press the ENTER key.
10. Check the flow measurement against the reference flow
meter again.
Operating Instructions