Question: Regarding radar level gauges
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1. Why do all radar level gauges on the market use HART communication? Can’t other protocols be used? 2. Why is their output always 4--20MA? What about other values instead? Is it mutual plagiarism? 3. Can’t radar level gauges use wireless communication? Why pull a wire? I’m a beginner; I don’t have any practical experience. The question might be due to ignorance; those who are knowledgeable kindly offer their guidance! !
4~20mA is a signal that is widely used; there are also other communication protocols, such as SAAB’s radar RL1/2 protocol, which uses MODBUS for communication with the backend. Please add more.
The Hart communication protocol is the most mature and widely recognized protocol for use in factories; it makes use of two layers out of the seven layers of the communication protocol hierarchy. The Hart protocol allows signals to be superimposed on 4-20mA signals, enabling the transmission of digital signals alongside analog signals; this is a typical feature of electric three-parameter instruments. Over time, only instruments that use digital signals will remain. 4-20mA instruments have their own advantages; a circuit power failure can be easily detected. Wireless communication is possible, but it’s way too expensive; how much do radar level gauges cost anyway? Wireless communication involves protocol conversion, which inevitably increases the DCS scanning cycle and raises the system load as well. Wireless communication is generally not used in factories, as it is unstable and prone to interference. Another factor is cost. Our equipment isn’t mobile anyway, so why use wireless?
There are wireless communication options; Emerson is promoting them now.
Reply to 3# xcs5506: Thank you very much for your reply! Just a question: Is the echo analysis or filtering of radar level gauges done by the device itself or on a computer at the terminal? Is the liquid level value directly given on the Hart line? What is echo analysis software? I’m a student in this major, so I don’t know much about it. Thank you for the guidance! !
Reply to 5# zcc02081016: It directly converts the signals to analog and digital forms on the surface; the analog signal represents the liquid level value, while the digital signals represent various parameters of the instrument as well as its status. I really have never encountered rollback analysis software.
Reply to 6# xcs5506: Thank you very much
Which company in China has managed to use 4G data signals to transmit the signals from the radar debugging panel, thereby enabling remote debugging?