Recent Valves, Actuators & Regulators Discussions
Similar Posts
Corrosion-Resistant Materials in Chemically-Hostile Valve Applications
Corrosion-Resistant Materials in Chemically-Hostile Valve Applications
new DVC not communicating with HART communicator
Interrogating a DVC type HC positioner with a HART 475 communicator
DVC6030 - HART Not Communicating at 20mA with SLS Two-state output channel?
Share

Use of 250ohm resistance in HART Communication?

Why is it necessary to use a 250ohm resistance in HART communication?

afnanumar
  • Jonas Berge
    It doesn't have to be exactly 250 ohm. Anything from 230 - 1100 ohm will do

    The reason it is required is that the HART signal is transmitted as a current and received as a voltage. The resistor works as a shunt that converts the transmitted current to a voltage the other device receives. The second reason it is required is because a DC power supply will short circuit the AC HART signal. The resistor prevents this from happening.

    Note that this resistor is only required for transmitters. It is not required for positioners.

This is the official online community site of the Emerson Exchange, a forum for the free exchange of non-proprietary information among the global user community of all Emerson's products and services. Our goal is to improve the efficiency and use of automation systems and solutions employed at members’ facilities by sharing our knowledge, experiences, and application information.

Community Guidelines | Legal Information | Privacy Policy | Contact Community Manager

Website translation provided by Website Translator

© 2015-2026 Emerson Exchange. All rights reserved.