Signal in hart protocol, Electrical Engineering

What is the significance of "4-20 mA" signal in hart protocol?

Ans) the HART protocol is an old Frequency Shift Keying way of distribution data, typically from highway sensors. This is a very old standard by today's standards there are so much better ways to send data. Of course, 4-20 ma loops are even older, dating back over 50 years, and still in common use. Must be something good about it - it is easy.

 

4-20 ma loops are a way to send an analog value, like temperature / position, over a pair of wires. It is easy on the surface, 4 mA is the minimum, and 20 mA is the maximum of the range. The cool thing about this is that it is stable current, not a voltage, so line resistance does not matter. Anything, constant current looks like an open circuit, so it is supposedly immune to noise (by in reality it still has noise pickup problems). Though, why not 0 to 20 mA the cool thing is you can power the remote sensor. You are running a current by the remote you have a voltage at the driving end why not use some of that power to run the electronics in the sensor? Thus, if the sensor pulls less than 4 ma and you make the range 4-20, you always have sufficient current to power the remote at the similar time.

 

 

Posted Date: 4/6/2013 2:42:47 AM | Location : United States







Related Discussions:- Signal in hart protocol, Assignment Help, Ask Question on Signal in hart protocol, Get Answer, Expert's Help, Signal in hart protocol Discussions

Write discussion on Signal in hart protocol
Your posts are moderated
Related Questions
Find Dispersion Relation for Free Electron Question: Find the dispersion relation for a free electron, and, thus, observe the relation between its rest mass and effective ma

State the advantages and disadvantages of alloying steel with silicon for use as magnetic materials in transformer and electric machines. Extensive utilize, is made of iron-sil

find the net value of power if an average value of energy is assumed to be $0.05/KWh, the capacity value is $30/kw-yr ...

Calculate the value of resistor: 1.  What are the significant differences in the way ammeters and voltmeters are connected. If an ammeter reads 2.5 A for a period of 4 minutes

Q. What do you understand by progressive control? Progressive Control: Step by step system is an example of progressive control. The connection is set up in stages, in response

Q. The truth table for F(A,B,C) = Mi (0, 1, 6, 7) is as follows: (a) Express F in a canonical product-of-sums form. (b) Minimize F in a POS form and obtain a possible re

Q. Practical properties of operational amplifiers? To achieve voltage gain and consequently power gain, the op amp must be biased by a dc source. The biasing network is compris

I want to know whether the circuits for both methods(linear polarization resistance and electrochemical impedance spectroscopy) are same or not?

Charge density In a semiconductor

This assessment requires you to reflect on an intercultural communication event that you have experienced between yourself and an Australian. a)  Describe the event without eval