一种支持RS485和HART通讯的压力变送器
By integrating RS485 and HART communication modules, the pressure transmitter solves the error problem caused by the single communication protocol in the existing technology, realizes low cost and high precision multi-protocol support, and ensures the stability of the system and the stability of the current output.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- FUZHOU CHANGHUI AUTOMATIZATION SYST CO LTD
- Filing Date
- 2025-06-27
- Publication Date
- 2026-07-17
AI Technical Summary
Existing pressure transmitters typically only support a single communication protocol, leading to incompatibility in environments requiring the mixed use of RS485 and HART protocols. In analog physical control systems, errors exist between analog signal output and digital signal transmission, increasing system costs.
Design a pressure transmitter that supports RS485 and HART communication. The RS485 and HART communication modules are integrated using MAX3485 and DS8500 chips. Combined with the SWP_CF230A microcontroller processor, a low-power design is achieved to ensure the stability and accuracy of the communication protocol.
This technology enables pressure transmitters to support both RS485 and HART communication without increasing hardware costs, reducing system errors and improving system accuracy and reliability. Furthermore, its low-power design ensures the stability of the 4–20mA current output.
Smart Images
Figure CN224518006U_ABST
Abstract
Claims
1. A pressure transmitter supporting RS485 and HART communication, characterized in that: The transmitter includes a main board (4) and a terminal block (7) connected thereto. The main board includes an RS485 communication module and a HART communication module. The terminal block includes a first terminal block connected to the RS485 communication module and a second terminal block connected to a power supply line. The second terminal block is also connected to the HART communication module, and the power supply line is used as the output line for collecting pressure values.
2. A pressure transmitter supporting RS485 and HART communication according to claim 1, characterized in that: The transmitter includes an aluminum front cover (1), a plastic display shell (2), a display panel (3), a main board (4), a main body (6), wiring terminals (7), and an aluminum rear cover (8) arranged in sequence; a pressure sensing head (9) connected to the main board is provided at the bottom of the main body; The first and second terminals of the wiring terminal are the first terminal combination, and the third and fourth terminals are the second terminal combination.
3. The pressure transmitter supporting RS485 and HART communication according to claim 1, characterized in that: The RS485 communication module includes a MAX3485 chip.
4. The pressure transmitter supporting RS485 and HART communication according to claim 1, characterized in that: The RS485 communication module has a built-in ESD protection circuit.
5. The pressure transmitter supporting RS485 and HART communication according to claim 1, characterized in that: The HART communication module includes a DS8500 chip.
6. The pressure transmitter supporting RS485 and HART communication according to claim 1, characterized in that: The HART communication module has a built-in load resistor and a HART modem.
7. The pressure transmitter supporting RS485 and HART communication according to claim 1, characterized in that: The motherboard is equipped with a main control module, which is based on a microcontroller. The microcontroller is connected to the power interface, LCD screen and button interface, sensor interface, JTAG software emulation interface, RS485 communication interface and HART communication interface. The RS485 communication interface supports the standard MODBUS-RTU protocol.
8. The pressure transmitter supporting RS485 and HART communication according to claim 7, characterized in that: The microcontroller adopts a processor with a core; the processor has a running speed of 36 MHz, standby power consumption less than 1 μA, supports a wide voltage range of 2.2 V to 3.6 V and a working temperature range of -40 ℃ to 105 ℃; The LCD screen is an FSTN segment screen.
9. The pressure transmitter supporting RS485 and HART communication according to claim 7, characterized in that: When the pressure transmitter is powered on and the microcontroller is initialized, the microcontroller uses its built-in SARADC to sample the pressure sensor head using the pressure compensation temperature and pressure signals. The sampled values are then corrected by the MCU using a two-dimensional compensation temperature and pressure table to obtain the correct pressure value. This correct pressure value is written into the MCU's communication-related registers for subsequent communication reading, and the value displayed on the LCD screen is refreshed.
10. The pressure transmitter supporting RS485 and HART communication according to claim 1, characterized in that: A 250Ω resistor is connected in series at the power supply line, and HART communication signals that can be connected to an external HART handheld device are led out from both ends of the resistor.