What are the two common transmitter configurations used with HART?

What are the two common transmitter configurations used with HART?

• A. USB-powered and Ethernet-powered transmitters.
• B. 2-wire loop-powered transmitters and 4-wire transmitters.
• C. Battery-powered and solar-powered transmitters.
• D. Wireless-only transmitters and fiber-optic transmitters.

Answer: (B)

HART communications run over a 4-20 mA current loop, and there are two common transmitter configurations that support this: 2-wire loop-powered transmitters and 4-wire transmitters. In the 2-wire setup, the transmitter both powers itself and carries the measurement signal on the same loop current, with the digital HART data superimposed on top of the 4-20 mA signal. In the 4-wire configuration, the transmitter has its own separate power supply, while the current loop still carries the 4-20 mA signal for the measurement, allowing the transmitter to draw power independently of the loop. In both cases, HART data can ride on the current loop without interrupting the analog output. Other power or media options like USB-powered, Ethernet-powered, battery/solar, wireless, or fiber-only configurations aren’t the standard ways HART field transmitters are commonly powered or configured, so they aren’t the typical two configurations used with HART.

HART communications run over a 4-20 mA current loop, and there are two common transmitter configurations that support this: 2-wire loop-powered transmitters and 4-wire transmitters. In the 2-wire setup, the transmitter both powers itself and carries the measurement signal on the same loop current, with the digital HART data superimposed on top of the 4-20 mA signal. In the 4-wire configuration, the transmitter has its own separate power supply, while the current loop still carries the 4-20 mA signal for the measurement, allowing the transmitter to draw power independently of the loop. In both cases, HART data can ride on the current loop without interrupting the analog output. Other power or media options like USB-powered, Ethernet-powered, battery/solar, wireless, or fiber-only configurations aren’t the standard ways HART field transmitters are commonly powered or configured, so they aren’t the typical two configurations used with HART.