Blocking Distance; Measuring Frequency Spectrum - Endress+Hauser Levelflex FMP51 Modbus Technical Information

Blocking distance

Measuring frequency
spectrum
14
The upper blocking distance (= UB) is the minimum distance from the reference point of the
measurement (mounting flange) to the maximum level.
R
LN
 3 Definition of blocking distance and safety distance
R Reference point of measurement
LN Probe length
UB Upper blocking distance
E Empty calibration (= zero)
F Full calibration (= span)
SD Safety distance
Blocking distance (factory setting):
• with coax probes: 0 mm (0 in)
• with rod and rope probes up to 8 m (26 ft): 200 mm (8 in)
• with rod and rope probes exceeding a length of 8 m (26 ft): 0.025 * (length of probe)
The specified blocking distances are preset on delivery. Depending on the application these
settings can be changed.
For rod and rope probes and for media with DC > 7 (or generally for stilling well/bypass
applications) the blocking distance may be reduced to 100 mm (4").
Within the blocking distance, a reliable measurement can not be guaranteed.
A safety distance SD can be defined in addition to the blocking distance. A warning is generated
if the level rises into this safety distance.
100 MHz to 1.5 GHz
UB
SD
E
F
Levelflex FMP51 Modbus
100%
0%
A0011279
Endress+Hauser