Table 41 - Minimum Blocking Distances And Transition Zones For The Various Probe Types - Honeywell SLG 700 Option Manual

Centering Disk Type:
This parameter identifies if a centering disk is present and if so the material that it is made off. If the
centering disk was ordered with the transmitter this will be correctly set when the transmitter leaves
the factory.
Centering Disk Diameter:
If the Centering Disk Type is not set to None, an additional parameter is required to specify the
diameter of the disk. If the centering disk was ordered with the transmitter this will be correctly set
when the transmitter leaves the factory.
Probe Propagation Factor:
Propagation factor will be factory set for the probe type ordered. If the probe is changed or a customer
supplied probe is used, this value may need to be adjusted to scale the apparent distance to product
appropriately. Consult Honeywell for details.
Blocking Distance Low:
Blocking distances are areas of the sensor reading range where it is not desirable to search for
reflections, possibly due to poor signal to noise ratios. The Blocking Distance Low is the distance
value measured starting from the Probe End. For a wire probe with an end weight, the end of the probe
is considered to be the top of the end weight. The transmitter will not attempt to make a reading in this
area. A minimum value is predefined by the factory to be the same as the Low Transition Distance.
The minimum value for Blocking Distance Low, as well as transition distances, is shown in Table
Blocking Distance High:
Blocking distances are areas of the sensor reading range where it is not desirable to search for
reflections, possibly due to poor signal to noise ratios. The Blocking Distance High is the distance
value measured starting from the Sensor Reference Plane. The transmitter will not attempt to make a
reading in this area. The factory-set blocking distance is set to the transition distance high. It is
recommended that the blocking distance is set to the largest value the measurement can tolerate and
that the loop current is adjusted to reach maximum before level reaches the blocking distance. The
minimum value for Blocking Distance High, as well as the transition distances is shown in the table
below.
Transition zones
Transition zones are areas close to the process connector and close to the end of probe where
measurements have reduced accuracy, see table below.
For more information on transitions zones for the various sensor configuration (i.e. coax, rope, rod,
HTHP, etc.), refer to SLG 700 SmartLine Level Transmitter User's manual, #34-SL-25-11.
Table 23 - Minimum blocking distances and transition zones for the various probe types
Probe Media in Tank
Type
Rod/Wire Water (DC=80)
Rod/Wire Oil (DC=2)
Coax Water (DC=80)
Coax Oil (DC=2)
Page 138
Minimum Blocking Upper
Distance High Transition
[cm] Zone, Tup [cm]
9 13
7 14
5 14
5 8
FOUNDATION Fieldbus Option User's Guide
Minimum Lower Transition
Blocking Zone, Tlow [cm]
Distance Low [cm]
0 1
0 12
2 0
6 7
23.
Rev. 3.0