Emerson Rosemount 5408 Reference Manual page 133

Reference Manual
00809-0100-4408
Change the upper null zone
The Upper Null Zone defines a zone close to the transmitter where echoes are ignored.
This zone can be extended to block out disturbing echoes at the top of the tank.
Prerequisites
Note
Make sure the Upper Range Value (100%/20 mA) value is below the Upper Null Zone.
Measurements are not performed within the Upper Null Zone.
Procedure
1. Identify desired Upper Null Zone using the echo curve plot.
2. Set the desired Upper Null Zone value.
Rosemount 5408 and 5408:SIS Level Transmitters
a) In Rosemount Radar Master Plus, start the echo curve reading, see
echo curve.
b) View the echo curve plot to find out if there are disturbing echoes close to
the transmitter.
a) Under Configure, select Level Setup → Antenna.
b) Under Advanced, type desired Upper Null Zone, and then select Save.
Figure 7-10: Upper Null Zone
B
A
100% (20 mA)
C
0 1 000
A. Upper Null Zone
B. Disturbance echo
C. Amplitude threshold
D. Product surface echo
D
2 000 3 000 4 000 5 000
Service and troubleshooting
February 2020
Using the
meter
3.0
2.5
2.0
1.5
1.0
0.5
0
6 000 7 000 mV
133