43
10.7 Display unit replacement
THE REPLACEMENT OF THE DISPLAY UNIT DOES NOT
REQUIRE TO RE-CALIBRATE THE TEMPERATURE.
10.7.1 Disconnecting the old display unit
• Unscrew with the 2.5 Allen key the 2 screws (A) of the battery
holder and pull it out as shown on Figure 10-11.
• Unscrew with the 2.5 Allen key the 4 screws (B) of the display
unit and pull it gently out of the electronic box, as shown on
Figure 10-11.
• Disconnect the tape plug, item (C) shown on Figure 10-6.
10.7.2 Connecting the new display unit
• Connect the tape plug to the new display unit.
• Put back the new display unit in the electronic box; tighten
the 4 screws (B) of Figure 10-11.
• Reinstall the battery holder with the 2 screws (A) of
Figure 10-11. Refer to Figure 10-4 page 40.
• Check that the unit is working properly, as described in 9.8.
10.8 Verication and certication of tapes
The tape has to be periodically inspected for breaks, kinks, wear
and illegible numbers.
As the tape is a cable it might be necessary to check its
electrical conformity. Refer to section 11.9. It is necessary also
to check it for accuracy regularly according to current National
or International Standards, as API “Manual of Petroleum -
Measurement Standards - Chapter 3 - Tank Gauging - Section
1A - Standard practice for the manual gauging of petroleum
products in stationary tanks” or IP “Petroleum Measurement
Manual - Part III - Manual Tank Gauging - Section 1 - Non-
Electrical Methods” or relevant ISO standards.
In such a case it is important to remember that the bottom
of the sensing probe is 4 mm lower than the zero of the tape,
thus to assure that the electrical zero coincide with the tape
zero.
It is also important to remember that the nominal tension at
which the tape was produced is marked on each beginning
of tape and is normally 6 N (1,3 lb). If tensioned at 44,5 N
(10 lb) as per API this will result in a additional elongation up
to 3.7 mm over 30 meters.
This periodical verication can be done at the factory or in a
Service Station.
To Next Page
Loading...
