4-20ma manual controller

You can also follow us on Facebook and Twitter to receive daily updates. One thing I noticed was not mentioned in the wiring of the loops. The limitations and effects of circuit impedance of the loop. I see issues on a regular basis where technicians and engineers have issues with their current loops functioning properly. I have them check the circuit impedance and this is usually the issue, and they have to add a resistor either in parallel or series depending on the requirements.

As per my understanding, the most common used configuration of modern mA transmitters is Two Wire Loop Powered Transmitters.

Just two cable cores are required to connect from the transmitter to control system. Such loop powered transmitters with HART are very popular in the transmitter market and able to cover lots of commonly used process measurement variables such as Pressure, Temperature, Flow, Level and simple Quality pH, conductivity, moisture, etc. The mA signal flow through separate line and not through 24V dc. Is my understanding is correct? Only wiring is a change. About the author.

S Bharadwaj Reddy. How a mA Transmitter Works? Free Control Valves Course. Don't Miss Our Updates. Be the first to get exclusive content straight to your email. We promise not to spam you. You can unsubscribe at any time. Recommended Articles. Good Point. Thanks for sharing. What should be the value of resistance? And how it should be calculated?

Plz explain. Congratulations an excellent contribution to the area of instrumentation Reply. Good Explanation Reply. The relationship between these two signals depends entirely on the response of the controller.

There is no reason to ever expect the PV and MV current signals to be equal to each other, for they represent entirely different variables. In fact, if the controller is reverse-acting , it is entirely normal for the two current signals to be inversely related: as the PV signal increases going to a reverse-acting controller, the output signal will decrease. You can also follow us on Facebook and Twitter to receive daily updates.

Thank you for this information. I have always wanted to understand mA signal, but now I have understood it with your help. Don't Miss Our Updates. Be the first to get exclusive content straight to your email. We promise not to spam you.

You can unsubscribe at any time. Recommended Articles. Thank you sir for the information. Very Good information on mA current signals. I have always wanted to understand mA signal, but now I have understood it with your help Reply.

In the field, for non mA instruments, how can you tell if they are analog or discreet? Thank you sir… Reply. Thank u sir…. Muito obrigado pelo artigo!