HART Communicator Not Recognizing Transmitter?

HART Communicator Not Recognizing Transmitter?

In this video, we will demonstrate a question we get from customers about the inability of their HART communicator to recognize a transmitter. We see this issue when there is not enough loop resistance between the power supply and the transmitter, and also when we are bench testing close to a regulated power supply or a very short wire run in the field.

To increase the resistance we will demonstrate how adding a 250 ohm resistor in series will help the HART communicator recognize the transmitter.

For this demonstration, I have a regulated power supply, two wire cable, pressure transmitter, and a 475 HART communicator.

This first demonstration will illustrate when the pressure transmitter is wired to the regulated power supply without enough load resistance. When the communicator is initialized it does not recognize the pressure transmitter. As you can see the communicator indicates no device found.

In this next demonstration, I have swapped out the wire with different test wire that I soldered a 250 ohm resistor. This resistor is in series between the regulated power supply in the pressure transmitter. Now as I hook up to 475 and initiated it searches for to the pressure transmitter. Now that the HART communicator is communicating with the pressure transmitter. You will be able to change the needed software parameters.

In summary, if your communicator is not finding your HART devices adding a 250 ohm resistor in series should help your communicator to connect.

If you should have any further questions or concerns please don’t hesitate to contact us at automation service.

Visit our Complete Guide to Rosemount® Pressure Transmitters to learn more about remanufactured 3051 transmitters.

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