Measurement - Honeywell SLG 700 User Manual

Upper Product/Lower Product:
For liquid products the dielectric constants vary much more. For the two liquid applications, the
value entered for the Upper Product Dielectric Constant will have a significant impact on the
accuracy of the reported Interface Level.
Two Liquids Flooded, Two Liquids Non-Flooded. Entering of the correct value for the DC of
the Upper Products ensures accurate measurement of the Interface, because the speed of
the measuring signal varies with the DC of the Upper Product.
To aid in the selection of the correct DC value for the liquid products, the PC based user
interfaces offer the ability to select the product type from a list that will automatically populate
the DC entry field, such as the Select from list... option, as shown in Figure 9.
Maximum Filling Rate:
This parameter indicates the maximum rate at which the tank is expected to be filled or emptied.
This allows the transmitter to collect data over the correct area of the probe so that the
surface and/or interface positions can be tracked effectively and aids in the rejection of false
reflections that might look similar to the correct reflections. The valid range is between 0.04-
0.2m/s (0.1312-0.656ft/s). The sensor uses this value to discard erroneous echoes. It is
recommended that a value somewhat larger than that expected from typical fill and draining
operations is entered, typically at least 0.1 m/s.
7.7.5

Measurement

Most customers are more interested in the height of the liquid surface or interface relative to some
lower datum point, such as the bottom of the tank, rather than the transmitter's reference plane.
Measurements made relative to this lower, user-defined datum point are referred to as levels to
distinguish them from the distances measured from the transmitter's datum point. In order to
convert distance measurements to level measurements, the following parameters are used to
describe the geometry of the installation:
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Figure 10: Basic Configuration – Measurement
SLG 700 Series HART Option User's Manual
Revision 5