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5.3.
P
ROPERTIES OF
VF05
T
WO
-W
IRE
M
ICROWAVE
L
EVEL
T
RANSMITTER
This chapter discusses the following topics:
- How does the transmitter measure the level, what factors play a role?
- Setting up and illustrating the measuring scale of the device in five possible ways.
- The role of gain adjustment in measurement.
-
What is a “Threshold line” and how can it be changed?
5.3.1.
Level Measurement
–
Level reflection, Threshold Line and Automatic Gain Adjustment
After connecting the power supply, the device will start operating:
1. It measures the reflected signals above the threshold line with the gain amplitude determined by the voltage amplitude and adjusted by cyclic repetition.
2. Determines the signal with the maximum amplitude that corresponds to the level reflection.
The following figure is a snapshot of the HyView -
“Echo Chart” function, typically for a measured material.
-The ADC values of the radar digitizer are located on
the vertical axis. The ADC value of 4095 corresponds to a radar signal with an amplitude of 3.3V. The distance on the horizontal axis.
1
Radar reference pulse emitted (transmitter signal or ping)
2
Flange reflection / flange pulse (does not occur with coaxial probe)
3
Non-material level reflection (parasitic, such as stirrer)
4
Reflection of measured medium’s level
5
Zero level distance (in this case coincides with the echo of the probe end)
6
Measured distance
7
Main threshold line.
For setting up, refer to
"5.1.2.5 Setting the Threshold"
8
Threshold mask (to mask disturbances that cross the main threshold line)
For setting up, refer to
"5.1.2.5 Setting the Threshold"
