Reviewing The Spacing Method; How To Use The Spacing Offset - Siemens SITRANS FUG1010 IP65 NEMA 4X Instruction Manual

Section 4

4.4.4 REVIEWING THE SPACING METHOD

The flowmeter analyzes your transducer selection, mounting mode and pipe size to determine the best
way to install your transducers. It will recommend the use of either a mounting track, a spacer bar, or
independent mounting. A special "weld seal" transducer housing assembly may have been provided.
Refer to any special housing drawings supplied (see Appendix C). The flowmeter will list the part number
of a mounting track or spacer bar. If it decides upon independent mounting, it will report the distance
required between the two transducers. In this case, you have to make sure that when you mount the
transducers, the space between them equals the length specified in the Ltn menu cell. See Section 5 for
details on how to accomplish this.

4.4.5 HOW TO USE THE SPACING OFFSET

After you select the mounting method, the flowmeter checks your entries for pipe size, transducer type
etc. and then recommends a spacing offset. This is the first step in establishing the correct distance
between the transducers. Spacer bars and mounting tracks utilize number indices (labels) to simplify
transducer placement. One transducer is located at the Reference position, while the other one is lo-
cated at the Number Index position. The Number Index cannot be directly edited. However, the Spacing
Offset can be changed via its option list. Changing the Spacing Offset will alter the reported Number
Index. Maximum spacing offset provides moderately greater signal levels but, in some cases, slightly
decreased zero flow stability.
If the flowmeter reports "Use Ltn," you have to measure the distance between the upstream and down-
stream transducers. The flowmeter issues the actual distance between the transducers in inches or
millimeters (See Ltn). Please consult Section 5 for details on how to use the Ltn measurement. Note that,
even though using Ltn does not call for the physical use of the Number Index, you can still change the
Spacing Offset to influence the strength of the transmit signal.
FUG1010GCN uses a pair of precisely matched transducers. Therefore, you can select either one for the
Reference position. You must connect the Up transducer cable to the transducer mounted on the up-
stream side of the mounting track. This lets the meter display the flow direction correctly.
It is important that you note each transducer's serial number and its Index position during the original
installation because to reinstall the flowmeter successfully, you must remount each transducer in its
original position. Transducer pairs have matching serial numbers except for the appended letters "A" and
"B." This helps you to identify each transducer.
To select a different Spacing Offset
To access to [Spacing Offset] option list press
To move the cursor to the desired offset press
To store selection press
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