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Interface Applications
It is not uncommon for interface applications to have an emulsion layer form between the
two media. This emulsion layer may pose problems for Guided Wave Radar as it may
decrease the strength of the reflected signal. Since the properties of this emulsion layer
are difficult to quantify, applications with emulsion layer should be avoided with SITRANS
LG200. These applications should be considered with Capacitance Technology.
Single Rod Applications
Nozzles
Nozzles can create false echoes that can cause diagnostic messages and/or errors in
measurement. If BAD CAL PARAMTRS is displayed when first configuring the instrument:
1.
Ensure the PROBE LENGTH as entered in the software is equal to the actual probe
length as noted on the nameplate. This value must be changed if the probe is cut
shorter from the original length.
2.
Increase the Blocking Distance value until the message is eliminated; 20 mA point
may need to be lowered.
3.
Increase the DIELECTRIC RANGE a small amount to aid in reducing echoes in nozzle.
Increasing the DIELECTRIC setting reduces the gain, which may cause instrument to
lose level of lower dielectric media; consult factory.
Obstructions
If the level reading repeatedly locks on to a specific level higher than the actual level, it
may be caused by a metallic obstruction. Obstructions in the vessel (e.g., pipes, ladders)
that are located close to the probe may cause the instrument to show them as level.
1.
Refer to "Single Rod Probe Clearance Guidelines" on page 32.
2.
Increase the DIELECTRIC RANGE a small amount to aid in reducing echoes in nozzle.
Increasing the DIELECTRIC setting reduces the gain, which may cause instrument to
lose level of lower dielectric media; consult factory.
Coating/Buildup
The SITRANS LG200 and Single Rod probe were designed to operate effectively in the
presence of media building up. Some expected error may be generated based upon the
following factors:
•
Dielectric of the media that created the coating
•
Thickness of the coating
•
Length of the coating above the present level
Stratification/Interface
The SITRANS LG200 and Single Rod probe should not be used in applications where
media can separate and stratify creating an interface application (e.g., water over oil).
The circuitry will detect the lower level—the higher dielectric medium (e.g., the water
level).
Page 80
SITRANS LG200 – INSTRUCTION MANUAL
7ML19985KA02
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