Rosemount 3107, Reference Manual

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Reference Manual
00809-0200-4841, Rev BA
Section 3: Installation
December 2014
Section 3: Installation
Positioning of the transmitter
The positioning is critical, and should be the correct distance upstream from the flow structure
as stated in the relevant standard for your country. For example, in the ISO standards, the
distance should be four to five times the maximum height of the water (Hmax) for a thin plate
weir, or three to four times Hmax for a flume. For optimum accuracy, position the transmitter’s
front face at a height equal to the sum of the maximum flow depth plus the transmitter
deadband of 12.2 in. (300 mm) plus an extra 2 in. (50 mm).
Figure 3-3. Choosing the height position above a flow
A. Transmitter front face
B. Hmax
C. Transmitter bottom reference = Hmax + 12.2 in. (300 mm) + 2 in. (50 mm)
It is important that the bottom reference of the transmitter should be related to the datum of
the primary measuring device ( Figure 3-4 ).
Figure 3-4. Bottom Reference of a flume or weir
A. Transmitter bottom reference C. Approach channel
B. Primary element (e.g. flume, weir) invert D. Flow
A
B
C
D
A
C
B