5
Signet 8250-2 Level Transmitter
Custom point #10
3000 gal.
Custom point #1
0 gal.
Custom point #2
45 gal.
Custom point #3
118 gal.
Custom point #4
160 gal.
Custom point #5
250 gal.
Custom point #9
1300 gal.
Custom point #6
380 gal.
Custom point #7
700 gal.
Custom point #8
1000 gal.
If Custom Shape is selected in the Options menu, you can de
fi
ne
from two to ten Custom Points to establish the relationship of
level to volume in the vessel.
• Select Manual level Measurement mode to edit both level and
volume data (dry con
fi
guration).
• Select Automatic level Measurement mode to accept the
sensor measurement of the Level, while you assign a
volumetric value to each custom point (wet con
fi
guration).
• Enter from 3 to 10 custom points to link level and volume
values.
• The
fi
rst custom point must be the lowest
fl
uid level in the
vessel. Each successive point must be greater than the
preceding point.
• The last point must be equal to or greater than the highest
fl
uid level in the vessel.
• A custom point should be located at each transition point in
the vessel shape (for example, at custom point #9, where the
shape changes from a cylinder to a cone).
• The more complex sections should be de
fi
ned with more
points. Notice that the conical section of the illustration has
been de
fi
ned by custom points 1 through 9.
• Simpler sections require fewer de
fi
ning points. Note that the
cylinder requires only custom points 9 and 10.
r
h
A
Length
5.2 Reference
5.1 Level and Volume Conversion in Custom Shaped Vessels
Pressure to level conversion:
Level = P ÷ (SG × D)
where P = Pressure
SG = Speci
fi
c Gravity of
fl
uid
D
= Density of water
With pressure in psi:
Level (meters) = 0.703069 × (P/SG)
With pressure in bar:
Level (meters) = 1.019715 × (P/SG)
Mass Conversion
m = D × SG × V
where m = mass of
fl
uid
D = density of water = 1000 kg/m
3
SG
=
Speci
fi
c Gravity of
fl
uid
V
= Volume of
fl
uid (m
3
)
m (kg) = 1000 × SG × V
Horizontal cylinder:
V = A × L
where A = area of segment
L = length of vessel
Level, volume and mass calculations performed by the 8250
include:
Vertical cylinder:
V =
π
× r
2
× h
where r = radius of cylinder
h = height of
fl
uid
Rectangular vessel:
V = w × L × h
where w = width
L = length
h = height
Volume Calculations
where r
=
radius of vessel
h = height of segment
(
)
⎥
⎦
⎤
⎢
⎣
⎡
−
×
⎟⎟⎠
⎞
⎜⎜⎝
⎛
−
−
⎟
⎠
⎞
⎜
⎝
⎛
−
×
×
=
−
2
cos
1
2
h
rh
h
r
r
h
r
r
A
2
