Troubleshooting guide

169
Reference Manual
00809-0100-4308, Rev BA
Appendix D: Configuration Parameters
December 2014
Configuration Parameters
Upper Null Zone Defines how close to the device's Upper Reference Point a
level value is accepted. You can extend Upper Null Zone to
block out disturbing echoes close to the tank top. View the
Echo Curve to find out if there are disturbing echoes close to
the tank top.
This parameter should only be changed if there are
measurement problems in the upper part of the tank. Such
problems may occur if there are disturbing objects close to
the probe. By setting the Upper Null Zone, the measuring
range is reduced. See “Changing the Upper Null Zone” on
page 94 for further information.
Note
Measurements are not performed within the Upper Null Zone.
and level alerts located in the Upper Null Zone will not be
triggered. Always configure your level alerts below the Upper
Null Zone.
For narrow nozzles it may be necessary to increase the Upper
Null Zone (UNZ) in order to reduce the measuring range in the
upper part of the tank.
By setting the UNZ equal to the nozzle height, the impact on
the measurement due to interfering echoes from the nozzle
will be reduced.
See also section “Handling disturbances at the top of the
tank” on page 92. Amplitude Threshold adjustments may also
be needed in this case.
Nozzle height
UNZ