Siemens SITRANS FUS1020, Manual, Page: 112 / 251

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1020NFM-1D Section 5
5.4.7 SLURRIES
High-density undissolved solids (e.g., sand slurry) may cause application problems if present in suffi-
cient quantity to scatter the sonic beam significantly. Low-density solids, such as organic materials,
coal slurries and unaerated sewage sludge, are usually adequate sonic conductors and their sonic
impedance is very close to most liquids. Excessive mineral solids though could trigger the aeration
alarm.
5.4.8 TWO-PHASE LIQUIDS
Two-phase liquids (e.g., oil and water) cause some sonic beam scattering. However, these usually
conduct sonic beams sufficiently for proper operation (unless heavy aeration is present also). Two-
phase liquids with large quantities of different components, such as sand or free gas, could prove to be
too attenuative for transit-time operation. However, switching to Reflexor mode will keep the meter
operational under these circumstances.
5.4.9 VISCOUS LIQUIDS
Highly viscous liquids tend to “absorb” some of the energy of the sonic beam. This causes a reduction
of signal amplitude when compared to low viscosity liquids. However, most high viscosity liquids are
sufficiently conductive for acceptable operation. A low Valc % value usually indicates low sonic con-
ductivity.
5.4.10 TEMPERATURE AND PRESSURE RATINGS
We rate our 1021 and 1011 Universal transducers for operation up to 250°F. For higher temperature
applications the System 1010 series of flowmeters should be used. Please refer to Section 4 for flow
tube pressure and temperature ratings.
5.5 OVERVIEW OF SYSTEM 1020 MEMORY RESOURCES
System 1020 memory resources include both Read-Only-Memory (ROM) and battery-backed Ran-
dom Access Memory (RAM). The ROM memory contains the system operating instructions, on-line
help text, default data, and the pipe, transducer and liquid tables.
The flowmeter uses 1 Megabyte of RAM (standard) to provide three discrete storage functions:
Active Memory - Site Storage Memory - Datalogger Memory.
Upon creating a site, the meter copies all ROM-based defaults into the meter’s operational database,
the
Active Memory . This provides two advantages. First, RAM-based operation increases performance.
Second, this creates an immediate Site Setup, based on the meter’s defaults. To make the meter
operational, you just have to enter
required data (e.g., pipe and transducer data) and edit other default
settings to suit your application. When you program the meter, all your entries are retained in the Active
Memory. This enables you to use the meter immediately after finishing a Site Setup. You’re not limited
to one set of site parameters. You can copy site data from
Active Memory to Site Storage Memory .
Site Storage Memory provides permanent storage area for several inactive Site Setups. The multi-site
storage feature allows rapid reinstallation at many locations. All you have to do to reactivate an inactive
Site Setup is to recall it back into to
Active Memory . However, be aware that this action over-writes ALL
the data residing in the Active Memory area.
The Datalogger logs data collected at preset intervals during operation. It uses the system RAM re-
sources independently of Active Memory and Site Storage Memory . Therefore, data movement be-
tween Active Memory and Site Storage memory will not affect it directly. However, all stored data