Gelec PIT70000, Руководство пользователя и техническое руководство

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User’s & Technical Manual – P/I LEVEL TRANSMITTER PIT7000
GELEC Industrial Electronics PAGE 25
IMPORTANT CALIBRATION NOTES

In order to begin the calibration procedure, PIT7000 must be at its final installation
position with all connections (electrical/pneumatic) completed . The installation
area of PIT7000 must be under atmospheric pressure, during calibration and operation.

Ensure that you have a proper electrical and pneumatic layout. Refer to the PIT7000
manual and confirm that every part and connection of the electrical/pneumatic layout
meets the recommended requirements. Ensure that the air tubes are clean, smoothly
curved, not bended/blocked and without possible leakage.

After initial power supply, allow a warm-up time of 15 minutes before calibration .
This will allow PIT7000 components to achieve thermal stabilization and reach the
thermal state of normal operation. Without the warm-up time, the output signal during
operation may be slightly higher than the calibrated output signal (up to 1%).

Adjust the supplied air pressure to 1,5 bar . Different pressure can also be applied if it
is necessary , as long as it’s higher than the hydrostatic pressure in maximum level. It is
recommended that the applied pressure during calibration, will be the same with the
applied pressure during normal operation.

For maximum measurement precision, the fluid used in calibration procedure must
be the same with the application’s fluid . If this is not possible, you should use a fluid
with confirmed similar density. For example , you shouldn’t calibrate PIT7000 using
water, if it’ s going to be used in an oil tank. The fluid ’s temperature during calibration
should also be similar to the fluid ’s temperature during operation.

Fill the tank at a relatively low level and confirm that a constant and controlled
bubble stream (3-4 per second) is escaping the bubble tube’s V -notch . If you
observe a significantly different airflow rate, adjust it properly with the AIR FLOW
REGULATOR .

After any calibration procedure connect properly a multimeter, to confirm the
desired output behavior. The output during calibration stages provides the minimum
signal of the selected output range (for example 4mA, if the selected range is 4-20mA).

The two levels can be separately calibrated . You don’t have to calibrate both levels,
each time a change at one of them is needed. The device automatically reconfigures its
output linearization.