KROHNE OPTIFLEX 1300C EN - Manual (Page 128)

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TECHNICAL DATA
128
OPTIFLEX 1300 C
www.krohne.com 03/2014 - 4000172306 - HB OPTIFLEX 1300 R07 en
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.