SY 4-20mA to HART Two-Wire Programmable Transmitter IC

The SunYuan SY 4-20mA-HART is a cost-effective, compact, two-wire programmable 4-20mA to HART bus transmitter IC. Designed with loop-powered operation, it performs A/D conversion on the 4–20mA analog signal within online instrument and transmitter loops, generating a HART signal linearly migrated according to the configured range. When requested by a HART master, this HART signal is superimposed onto the 4–20mA analog signal and transmitted to the host for data acquisition.Featuring built-in reverse-polarity and overcurrent protection circuits, this integrated module is ideal for upgrading traditional transmitters and instruments to digital, smart control devices. It is widely applied in petrochemical, environmental monitoring, mining, and other industries for smart, remote monitoring of physical variables such as temperature, pressure, flow, and liquid level.In traditional industrial fields, physical parameters (e.g., temperature, pressure, flow rate, speed) are converted into analog current signals via sensor transmitters and sent directly to PLCs/DCSs, lacking digital capability for configuration and remote calibration. Integrating this two-wire programmable transmitter IC—capable of generating HART signals superimposed on the 4-20mA current loop—enables digital control upgrades. It allows remote monitoring and calibration across various HART-enabled master devices, including transmitters, instruments, PLCs/DCSs, and host computers.

The SY 4-20mA-HART transmitter IC features a two-wire, passive loop-powered wiring configuration. It is designed to add HART signal modulation and demodulation onto the 4–20mA analog signal transmitted between sensors, transmitters, and PLCs/DCSs/HART hosts, providing a digital interface for traditional transmitters.No external DC power supply is required for operation; the module is directly embedded into instruments and equipment by connecting it in series with the 4–20mA current loop. Through a HART master or field communicator, users can set multiple parameters—such as zero point, full scale, range, and units—enabling convenient field calibration and range migration.

The current signal and the read measurement value of the SY 4-20mA-HART loop exhibit a linear corresponding relationship, with a configurable maximum range limit of 60000 and a minimum limit of -60000. For example, given an input signal of 4–20mA and a configured lower/upper range limit of 0–10000, the relationship is mapped as follows: 4mA corresponds to a reading of 0, 12mA corresponds to 5000, and 20mA corresponds to 10000. Other measurement ranges follow the same proportional logic.