Siemens SITRANS FUH1010PVX, Operating Instructions Manual, Page: 90 / 226

2-24
1010BXFM-3 Section 2
2.4.4 REVIEWING THE SPACING METHOD
The computer 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. The computer will list the part number of a mounting
track or spacer bar. If it decides upon independent mounting, it will report the distance re-
quired 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 3 for details on how to accomplish this.
2.4.5 HOW TO USE THE SPACING OFFSET
After you select the mounting method, the computer checks your entries for pipe size, trans-
ducer 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 (i.e., predetermined mounting locations) to simplify transducer placement. One trans-
ducer is located at the Reference position, while the other one is located 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 computer reports “Use Ltn,” you have to measure the distance between the upstream
and downstream transducers. The computer issues the actual distance between the transduc-
ers in inches or millimeters (see Ltn, paragraph 2.4.8). Please consult Section 3 for details on
how to use the Ltn measurement. Note that even though using Ltn does not call for the physi-
cal use of the Number Index, you can still change the Spacing Offset to influence the strength
of the transmit signal.
The System 1010BX Interface Detector uses a pair of precisely matched transducers so you
can select either one for the Reference position. You must connect the Up Transducer cable to
the transducer mounted on the upstream side of the mounting track. This enables the meter
to 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 meter 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 select a Xdcr Mounting Mode:
To access the [Xdcr Mount] option list press
To move the cursor to the required mounting type press
To store selection press
ENT
Reflect mounting. This can be important if the liquid or pipe material exhibits high sonic
attenuation, thereby preventing operation in the Reflect configuration.
NOTE: We recommend using Direct Mount.