Endress+Hauser PROFIBUS Levelflex M FMP45 Operating Instructions Manual page 105

Levelflex M FMP45 with PROFIBUS PA
Endress + Hauser
Input
The reflected pulses are transmitted from the probe to the electronics. There, a microprocessor
analyses the signals and identifies the level echo, which was generated by the reflection of the high-
frequency pulses at the product surface. This clear signal finding benefits from the more than 30
years of experience with pulse time-of-flight procedures that have been integrated into the
development of the PulseMaster
The distance D to the product surface is proportional to the time of flight t of the impulse:
D = c · t/2,
with c being the speed of light.
Based on the known empty distance E, the level L is calculated:
L = E – D
Reference point for "E" see above diagram, Details → ä 57.
The Levelflex possesses functions for the interference echo suppression that can be activated by the
user. They guarantee that interference echoes from e.g. internals and struts are not interpreted as
level echoes.
11.3.2 Equipment architecture
On-site operation:
• with display and operating module VU331,
• with a Personal Computer, FXA291 and ToF Adapter FXA291 (USB) and the operating software
"FieldCare".
The FieldCare is a graphical operating software for instruments from Endress+Hauser that operate
based on the time-of-flight principle (radar, ultrasonic, guided micro-impulse). It assists with
commissioning, securing data, signal analysis and documentation of the measuring point.
11.3.3 Patents
This product may be protected by at least one of the following patents.
Further patents are pending.
• US 5,661,251 i EP 0 780 664
• US 5,827,985 i EP 0 780 664
• US 5,884,231 i EP 0 780 665
• US 5,973,637 i EP 0 928 974
®
Software.
Appendix
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