Flow Data Scatter And Damping; Considerations For Critical Applications - Siemens SITRANS F Operating Instructions Manual

Section 6
4. DO NOT mount the flow tube on a section of pipe that may be empty during zero flow. If this cannot
be avoided, then be aware that the system will not be able to measure flow until the pipe refills and
flow persists for long enough to drive all the air from the flow tube.
5. DO NOT run the transmit/receive cables in common bundles with cables from any other equip-
ment.
6. DO NOT mount the flow tube under water, unless you order a submersible cable kit and install it
according to factory instructions.

6.1.4 FLOW DATA SCATTER AND DAMPING

Use the slew rate and damping controls to smooth data response time to suit your application. The
default SmartSlew control provides excellent output regulation without sacrificing an instant response
to sudden flow changes. Therefore, we recommend SmartSlew for most applications. The Damping
control is particularly effective when one cannot avoid mounting the flow tube very close downstream
from a potential cavitation source such as a positive displacement pump.
6.2

CONSIDERATIONS FOR CRITICAL APPLICATIONS

All flowmeters depend on proper site flow conditions and installation to achieve precise, critical flow
measurements. Unfavorable factors such as liquid non-homogeneity or stratification and aeration/
cavitation increase the possibility of reduced accuracy. This applies to all flowmeters, regardless of
their design, sophistication, expense and published intrinsic accuracy. These factors become critical
when applications involve custody transfer, tenant billing, and nuclear or other safety-related flows.
Our System 1010 Universal Nema Flowmeters include provisions to minimize adverse flow conditions
to achieve extremely high accuracy. This requires closely following the instructions for proper equip-
ment selection, use of the correct clamp-on transducer or flow tube configuration and paying close
attention to installation instructions.
If your application requires critical measurement accuracy it is not realistic to simply install the flowme-
ter and expect optimum performance. Carefully review your piping configuration. Select the best mount-
ing location and install the transducers or flow-tube in strict accordance with the published instruc-
tions. This holds true even when the system is calibrated for enhanced precision at a flow laboratory.
Its precision can be impaired by not closely following the programming and installation instructions.
We recommend that all potential installers (especially critical installations) participate in our training
programs. Another possible alternative is to commission our trained professionals to start-up the sys-
tem for you.
To Obtain Technical Assistance
The operating program provides comprehensive diagnostics data. Using this data, our engineers can
analyze your system in relation to the application usage. A detailed analysis will provide solutions to
virtually any adverse application problem. Call our Technical Service Group for any assistance you
might require. Toll-free assistance is available every week day from 8:30 A.M. to 5:00 P.M. (EST) by
calling 800-275-8480. You can also request help via e-mail by contacting the Technical Service Group
at TSG.ultrasonicflow@siemens.com.
6-3
1010PFM-3G