Endress+Hauser FMR 231 - 7.7 Window suppression; Procedure

7.7 Window suppression
In the case of strong echoes from fittings or welds near to the antenna, all echoes within
a window B below the antenna tip can be suppressed
•
The datum point for the window B is the lower face of the process connection.
The factory setting is to the tip of the antenna.
•
All echoes within the window B are suppressed.
•
Since in certain circumstances the level echo could be suppressed (and there is
no guarantee that no other echo is present), a 10 cm safety zone extends in front
of the window.
•
The customer can set the response of the Micropilot to the case where product
enters this zone ("in safety distance").
•
The full distance "F" may extend only to the start of the window.
Procedure
# VH Entry Significance
1 If appropriate calibration and echo
suppression, Chapter 6.1 – 6.3
➤ Extended calibration
2 V3H5 B
V
Window
suppression
➤ Operating mode
3 V8H5 e.g. 1
H
Within safety
distance =
0: Warning
1: Alarm
2: Alarm
self-holding
3: Clear 2
Note!
•
The window suppression is automatically integrated into any previous echo
suppression map.
7.8 Plausibility
The plausibility check assesses the history of the measured value. It ensures that overspill
cannot happen without a previous alarm or warning. If the signal is lost in close proximity
to the antenna, i.e. in the critical zone where overspill might occur, the last valid measured
value is subject to a plausibility check. This ensures that a false echo from a lower level
cannot be evaluated as the level signal. Micropilot checks every new signal for plausibility
and outputs error E643 in the event of a non-plausible level value.
•
The critical zone starts 35 cm below the 100% level (F) and extends to the
antenna tip.
•
The plausibility check is automatically activated when one of the application
parameters 4, 5 or 6 is set in V0H3 during calibration. It can also be activated
manually in V8H6.
•
Error E643 can be set to act as a warning, alarm or self-holding alarm in V8H5,
see Chapter 6.5.
The plausibility check functions only when a false echo suppression has been performed,
see Chapter 6.1 or 6.2.
F
B
E
100%
20mA
0%
4mA
10 cm
safety zone
BA171Y57
Note!
Chapter 7 Trouble-Shooting Micropilot FMR 231
42 Endress+Hauser