KROHNE BM 70 A_P EN - Manual (Page 60)

Installation and operating instructions BM 70 A/P Page: 60 11/00
Group DA Display and signal output
No. Fault / Symptom Cause Corrective action
DA10 Display and signal output frequently
indicate the maximum level. Excessive amounts of vapour,
condensate or dust in the tank, or
heavy contamination (deposits
thicker than approx. 3 - 7 mm or
0.1" - 0.3") on the antenna. Clean antenna (install cleaning device
if necessary). If unsuccessful, enlarge
BLOCKDIST. under Fct. 3.1.2 (see
Sect. 8.6.3) or deactivate Fct. 3.5.6
BD-DETECT (see Sect.8.6.14).
Antenna cleaning operations cause
strong reflections. Activate digital input during cleaning
(marker 6
6
is ON), measurement
suspended (frozen), see Sect. 4.8.
DA11 Display and signal output indicate
sizeable step changes in the
direction of the maximum (possibly
also mimimum) level. Storage tank: BM 70 A/P mounted
centrically or on dome (manhole
cover). Change position of the BM 70 A/P. For
recommended distance from tank wall,
see Sect. 6.1.2, and note installation
conditions in Sect. 6.1.3!
Or activate "multiple reflection
identifier" under Fct. 3.5.5, see Sect.
8.6.14.
Process tank with extremely
turbulent product surface. Switch on tank type AGITATOR under
Fct. 3.5.9, see Sect. 8.6.16.
DA12 Display and signal output indicate
step changes:
during filling
→
upwards
during draining
→
downwards
Storage tank, smooth surface,
steady filling or draining procedures,
incorrect tank type set. Set correct tank type (STORAGE
TANK) under Fct. 3.5.9, see Sect.
8.6.16.
DA13 Signal output (recorder) shows
sinusoidal variations about the
actually measured value (deviation:
up to ± 2 cm) in the upper part of
the tank (approx 2 m). This has physical reasons and
occurs mostly with slow changes in
level when sources of interference
are located in the upper part of the
tank. Avoid all sources of interference in the
upper part of the tank. A bigger
antenna might help to solve the
problem.
DA14 Display and signal output indicate
constant measured values, although
the level changes. Fixed tank internals unfavourably
positioned, thus permanently
simulating a constant level to the
BM 70 A/P. No empty spectrum
recorded and/or measurements
carried out without empty spectrum. Activate the empty spectrum under Fct.
3.5.2 if measurements carried out
without empty spectrum. If empty
spectrum not recorded, record under
Fct. 3.5.2, see Sect. 8.6.12.
Digital input is activated,
marker 6
6
is ON, measurement
is suspended (frozen).
Deactive the digital input, see Sect. 4.8
DA15 Display and signal output indicate
measured values at the level of the
agitator blades. Tank with "difficult" agitator blades. Record new empty spectrum with "
MAX. VALUES" under Fct. 3.5.2. Or
change position of the BM 70 A/P on
the tank. Note conditions described in
Sect. 6.1.2.
DA16 Display and/or signal output
indicate incorrect conversion
values, but level indication is
correct. Conversion table set incorrectly. Reset conversion table with the PC-
CAT program.
DA17 Display and signal output go
suddenly to "zero" or block distance
limit when tank continuously topped
up. Level located in range of block
distance in front of antenna, see
Fct. 3.1.2 in Sect. 8.6.3. Avoid this operating condition or, if
empty spectrum (Fct. 3.5.2) is
sufficiently good, reduce block distance
(Fct. 3.1.2) as described in Sect.8.6.3.
Group M markers 1-6 & in display
No. Fault / Symptom Cause Corrective action
M1 markers 1-5
6
(one or several) ON. Reference(s) to possible faulty
measurements.
See Sect. 8.8 for significance of markers
and elimination of possible faults.
M2 marker 2
6
ON for long periods or
permanently.
Note: very strong reflection signal
(e.g. measurement in the stilling
well). Not important if measured value is
correct.
M3 marker 6
6
ON. Digital input is activated,
measurements suspended (frozen). Deactivate digital input, see Sect. 4.8.
Device located in block distance
detection range. Check conditions for block distance
detection, see Sect. 8.6.14.
M4 markers 3 and 4
6
ON.
Level indicator is "zero".
This is a status display and not an
error. This usually occurs on tanks
with dished bottom, when the tank is
empty, after the BM 70 A/P has
been switched on or after a new
empty spectrum has been recorded. Fill tank!