The illustration that follows shows a snapshot of what a user would see on an oscilloscope, if the
level and/or interface of products are measured.
Level measurement principle (direct mode)
Figure 8-1: Level measurement principle
1
Time 0: The electromagnetic (EM) pulse is transmitted by the converter
2
Time 1: The pulse goes down the probe at the speed of light in air, V1
3
Time 2: The pulse is reflected
4
Time 3: The pulse goes up the probe at speed, V1
5
Time 4: The converter receives the pulse and records the signal
6
The EM pulse moves at speed, V1
7
Transmitted EM pulse
8
Half of this time is equivalent to the distance from the reference point of the device (the flange facing) to the surface
of the product
9
Received EM pulse
CAUTION!
Interface measurement:
Interface measurement:
Interface measurement:
Interface measurement: The dielectric constant of the top liquid must be less than the dielectric
constant of the bottom liquid. If not, or if there is too small a difference, the device may not
measure correctly.
Te
gy Solutions
chnolo
Instruction Manual
Tek-Flex
4100A
www.tek-trol.com
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