+GF+ 2298 Bedienungsanleitung Seite 28

Type 2298 80 GHz Radar Level Sensor
5.2.7 P06 Far-end blocking
FACTORY DEFAULT: 0.0
In parameter P06, we can specify a level value below which the output will no longer follow any further level decrease. Far-end blo-
cking is used when objects at the bottom of the tank (mixer, heating coil, funnel, etc.) cause measurement uncertainty within this
range, e.g., because interfering echoes cannot be safely distinguished from the echoes of the measured surface. If an echo falls
within the far-end blocking range (LEV < P06), the device sends a special signal and keeps the level value defined here on the output
(see figure). The "Echo in far-end blocking range" flag indicates that the echo is in the far-end blocking zone. Regardless of this, the
"VALID" flag is active, but the "HOLD" flag remains inactive.
Far-end blocking can be deactivated with P06 = 0. Min. value: 0 / max. value: P04 – P05 – 5 cm (2")
P06
Measurement optimalization ➙ Far end (P06)
EView2
A.) Level or volume measurement
If the level drops below the value of P06: It keeps a level
•
value corresponding to P06 on the output and calculates the
derived values from it.
If the level goes above the far-end blocking limit: In level
•
or volume measurement mode, the programmed tank
dimensions are valid, so farend blocking does not affect the
measured or calculated values.
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B.) Open-channel flow measurement
Far-end blocking is usually applied to those low-level values,
below which exact volume flow cannot be calculated.
If the level in the flume drops below the blocking value:
•
The current loop output holds the value corresponding
•
to Q = 0.
For 0-value transmission via HART "No Flow"
•
If the level in the flume rises above the blocking value:
•
Flow value is calculated using the parameters specified in the
program, so remote blocking does not affect measured values.
Instruction manual