User Manual

Commissioning
Part No.: 4417.762_Rev07 SmartRadar FlexLine
Service Manual 6 - 73
In the table below some filtering figures are given.
6.5.2.6.2 Verification Pins
When a radar level gauge is installed on a pressurized tank, both ISO
and API suggest to use so-called verification pins to verify the radar
level measurement. Prime reason to use said verification pins is the
impossibility of doing a manual reference dip. With verification pins it is
possible to verify the correct reading of the radar measurement at
specific heights while the tank is in operation.
The SmartRadar FlexLine can be switched to measure the pin
positions. The reading can then be compared with the known position of
the pins. It is advised to have three verification pins:
 Pin 1 at approximately 80 - 90 % of tank height
 Pin 2 at approximately 50 % of tank height
 Pin 3 at approximately 10 - 20 % of tank height
Pin 1 should be above maximum safe fill (so, it can always be
measured), however there must be at least 0.6 m (2') free space from
pin 1 to cone end. All pin positions should be measured with 1 mm (1/
32”) uncertainty with reference to the ball valve.
The SmartRadar FlexLine can measure the position of the three pins
when the housing is rotated 90°. The verification pins are then ‘visible’
to the SmartRadar FlexLine. 
This can be done without closing the 1" (or 4") ball valve, as the
FlexLine housing is located above the tank separator. 
After the command “Measure verification pins” is given, the measured
positions of the three pins can be requested. The “real” position of the
pins (from tank drawing) and the “measured” position of the pins are
compared and a correction is applied.
After the SmartRadar FlexLine is placed in the normal (product
measuring) mode, the measurement is automatically corrected for the
found verification pin positions.
FIGURE 6-12 illustrates the correction method for verification pins.
Once the position of the verification pins is determined, the FlexLine can
be switched into verification mode to verify the measured (and
[Filter averaging
constant]
Approximate
noise reduction
factor
Maximum lag
[s]
Maximum lag
[distance]
50 1.4 0.1 0.1 * dL/s
70 1.8 0.25 0.25 * dL/s
90 3 1 1 * dL/s
95 4.5 2 2 * dL/s
98 7 5.5 5.5 * dL/s
99 10 11 11 * dL/s