Process Characteristics - Emerson 5301HxxxxxxxxxxxxxxZZ Series Reference Manual

Reference Manual
00809-0100-4530
2.7

Process characteristics

The Rosemount 5300 Level Transmitter has high sensitivity because of its advanced signal
processing and high signal to noise ratio. This makes it able to handle various
disturbances, however, the following circumstances should be considered before
mounting the transmitter.
2.7.1 Contamination/product build-up
Heavy contamination or product build-up on the probe should be avoided since it may
decrease the sensitivity of the transmitter and lead to measurement errors. In viscous or
sticky applications, periodic cleaning may be required.
For viscous or sticky applications, it is important to choose a suitable probe. For detailed
information on the maximum recommended viscosity and coating, see
Maximum measurement error due to contamination is 1-10 percent depending on probe
type, dielectric constant, contamination thickness and contamination height above
product surface.
Signal Quality Metrics (SQM) diagnostic option can give an indication of how good the
surface signal is compared to the noise, and when to clean the probe.
2.7.2 Bridging
Heavy product build-up results in bridging between the two probes in a twin lead version,
or between the pipe and inner rod for coaxial probes, and may cause erroneous level
readings, so it must be prevented. A single lead probe is recommended in these situations.
2.7.3 Foam
The Rosemount 5300 Level Transmitter measurement in foamy applications depends on
the foam properties; light and airy or dense and heavy, high or low dielectrics, etc. If the
foam is conductive and creamy, the transmitter may measure the surface of the foam. If
the foam is less conductive the microwaves may penetrate the foam and measure the
liquid surface.
2.7.4 Vapor
In some applications, such as high pressure boiling water, there is a heavy vapor above the
product surface that could influence the level measurement. The Rosemount Level
Transmitter can be configured to compensate for the influence of vapor.
2.7.5 Boiling hydrocarbons
For products with very low dielectric constants, such as boiling hydrocarbons and solids,
the threshold may need to be lowered, and/or the Probe End Projection (PEP) function
activated.
Reference Manual
Transmitter overview
April 2019
Table A-1.
23