HART Communicator Not Recognizing Transmitter?

Подписаться 978

Просмотров 12 тыс.

50% 1

In this video, I will be demonstrating 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 I 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.
So 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 800-325-4808. Our technical support team is here to help.
==========================
YOU MIGHT ALSO LIKE →
Need help calibrating your DVC6000? Click here to download our free calibration instructions: go.automationservice.com/dvc60...
If your plant is interested in a flow meter, click here to submit a quick quote request: www.automationservice.com/prod...
==========================
RECYCLE→
Is your manufacturing plant as green as it can be?
Take a look at our process controls recycling program. Our program is completely personalized and HASSLE FREE. Your department can earn credits toward future purchases of remanufactured process controls and Fisher® valves. We also reward your team for participating with our fun (and tasty) Reclamation Road Trip program.
Click here to learn more: : go.automationservice.com/learn...
==========================
CONNECT WITH US→
RU-vid Subscribe: ru-vid.com_...
Facebook: / automation-service-135...
Twitter: / reman_controls
LInkedIn: / 378711
==========================
Automation Service is the world’s largest remanufacturer of high-quality process controls. We are internationally recognized as the leading supplier of remanufactured transmitters, control valves & actuators, regulators, flowmeters & flowtubes, controllers, positioners, capillaries & sealed systems, transducers and more. We remanufacture products originally manufactured by Rosemount®, Fisher®, Foxboro®, Honeywell® and Moore®, and are proud to say that our products are “Re-Made in the USA.”
Automation Service
www.automationservice.com
Contact us: www.automationservice.com/cont...
Automation Service is the sole warrantor of this product and is NOT affiliated or endorsed by Fisher, Rosemount, or any other Emerson Process Management Company. Automation Service is not an FM Approved Repair Facility and cannot supply remanufactured or repaired FM Approved equipment for Hazardous Locations.

Наука

Опубликовано:

26 фев 2018

Ссылка:

Скачать:

Готовим ссылку...

Добавить в:

Мой плейлист

Посмотреть позже

Комментарии : 8

@ramachandrunichandana253 3 года назад

Hi Bob, Though adding a 270Ohm resistor is not helping communicator to recognize transmitter. What can be the other reasons?

@estebancasanovadelahoz. 2 года назад

EXCELENTE PREGUNTA.

@Waterboy-wh7mb 9 месяцев назад

Add a 250 ohm resistor. Not a 2700ohm resistor

@shatakshisinha4245 4 года назад

in spite of having the same arrangements , msg appears as " voltage detected on FF terminals" and no device is found. what to do sir?

@theinstguy 10 месяцев назад

Hopefully you figured it out by now, but you were on the wrong terminals on your HART.

@NasalChain 5 лет назад

Is the resistor must be higher than 250ohm?

@engyousif8404 2 года назад

No because the value of the resistance must be studied to achieve the voltage value from 1 to 5 volts this values you can do it with ohms law

@exisfohdr3904 Год назад

Not exactly true. The 1 to 5 vdc you refer to is based on the transmitter controlling the current in the loop to 4-20mA. If the resistor is 250 ohms, then when at 4mA the voltage drop across the rrsistor will be 1vdc, at 20mA 5vdc. You can use a 300 ohm resistor, but the voltages will be 1.2-6vdc. All that is required is sufficient enough resistance to create a voltage potential differences allowing the HART signal( mV amplitude AC signal) to not get waahed out. The amplitude of the signal must be large enough for the transmitter to recognize it. The value of the resistor you can use can be higher that 250 ohms so long as the max voltage drop of the resistor does not reduce the remaining voltage to rhe transmitter below it's minimum power requirements(found in manual. If providing 28vdc from supply, and transmittee requires 16vdc minimum, that leaves 12 volts of drop allowance at max current(22mA). 12vdc/.022A=545.44 ohms. In this case, I would not exceed 500 ohms to allow for line resistance.