HART host module 5700 uses an AD5700-1 HART chip, with isolation, surge protection, impact protection, overvoltage protection, reliable and stable performance, clean and smooth output waveform, TTL serial port output, and simple control. It can be directly connected to the instrument for testing, which is convenient for secondary development.
One end of this product is a standard UART serial port interface, and the other end can be directly connected to the HART instrument, so this product does not provide a schematic diagram.
Pin Introduction
1. The A and B ends are not positive or negative and can be directly connected to the load resistor of the HART smart transmitter.
2. RST reset pin, usually directly connected to the power supply.
3. RXD, TXD, OCD, and RTS are connected to the TTL serial port.
4. OCD is the serial port carrier detection, usually not connected. OCD is 1, indicating that the input waveform amplitude is greater than 120mV, and OCD is 0, indicating that it is less than 80mV.
5. RTS is high level, the module is in demodulation mode, otherwise it is in modulation mode. When connected to a single-chip microcomputer, it can be connected to an IO pin.
6. R/T is the transceiver indicator light, and the blue LED flashes when working.
7. PWR is the power indicator light, and the red LED is always on after the power is turned on.
8. Input power range: 2V~5.5VDC. (It is generally recommended to use 3V, 3.3V, 3.6V or 5VDC)

Function introduction
1. PWR is the power indicator light, red, always on when the power is turned on.
2. R/T is the receiving and transmitting status indicator light, blue light, flashing when working.
3. Bias output, stable signal, effectively filtering out background noise.
4. 1:1 electromagnetic isolation of input and output signals.
5. High-efficiency TVS tube two-stage surge and impact protection.
6. 50V, ESR DC-isolating coupling capacitor effectively protects input and output safety and has the function of protecting the power line from connection.
7. Can directly connect USB to UART or RS232 to UART interface chip and make a homemade HART modem.
8. Can be used for homemade handheld operator.
9. Can be connected to a single-chip microcomputer for system integration, used for process control of HART function.