KROHNE optiplex 1300 c, Handbook

Page: 70 / 95

Handbook OPTIFLEX 1300 C
OPTIFLEX 1300 C 70
OPTIFLEX 1300 C allows three thresholds to be modified manually:
•
Menu C.1.16.0 Level Threshold:
for identifying the top product surface,
•
Menu C.1.17.0 Interface Threshold:
for identifying the interface when there is more than one product in the tank and
•
Menu C.1.18.0 Probe End Threshold:
for identifying the end of the probe (important for TBF mode)
Use the signal screen in normal mode to identify the correct signal. This displays the biggest reflections in
terms of voltage amplitude/ mV against distance/m. Press the right button to select the next reflection and
read the values for each point.
Knowing the size of big reflections and their position, you can identify what the reflections are and then
raise the thresholds above the parasite signals while still remaining below the product surface signal
amplitude.
Level threshold
function C.1.16.0
The graph below shows what the user would see if the return signals were displayed on an oscilloscope.
The level threshold function is active from the flange return signal and is used to ignore an interference
signal from a protruding object above the product surface.
1 Initial pulse
2 Flange reflection (not present when coaxial
probe used)
3 Parasite reflection (limit switch)
4 Product level reflection
5 Level threshold (voltage amplitude decreases
in 2m or 6.5ft steps.
6 Offset - distance from the signal converter to
the flange
7 Distance to product level
Interface threshold
function C.1.17.0
When there is more than one product in the tank, a second threshold is required to measure interface level.
When the OPTIFLEX 1300 is switched on it will:
•
identify the closest reflection to the flange above the level threshold as being the level of the top product
and
•
identify the next largest reflection that is above the interface threshold as being the interface.