读取MODBUS网关与串口读取

pymodbus库使用教程（以Modbus RTU为例）

from pymodbus.client.sync import ModbusSerialClient as ModbusClient
from pymodbus.exceptions import ModbusException, ConnectionException
import logging
from pymodbus.client.sync import ModbusSerialClient
logging.basicConfig()
log = logging.getLogger()
log.setLevel(logging.DEBUG)
port = 'COM8'  # 替换为您的串行端口
baudrate = 4800  # 替换为您的波特率
parity = 'N'    # 替换为您的校验位
# 创建ModbusSerialClient实例，用于与Modbus服务器通信
client = ModbusSerialClient(method='rtu', port=port, baudrate=baudrate,stopbits=1, parity=parity)
def read_temperature_and_humidity(client):
    try:
        
        result = client.read_holding_registers(
            address=0, count=2, slave=1,unit=1)  # 读取输入寄存器的0x03 # 读两个寄存器

        if result.isError():
        
           print("读取错误:", result)
        return None, None

        # 将读取到的结果转换为温度和湿度
        registers = result.registers
        temperature_reg = registers[0]
        humidity_reg = registers[1]

        # 检查是否有探头错误
        if temperature_reg == 0x8000 or humidity_reg == 0x8000:
            print("探头错误")
            return None, None

        # 计算实际的温度和湿度值
        temperature = temperature_reg * 0.1
        humidity = humidity_reg * 0.1

        # 格式化温度和湿度值，保留一位小数
        temperature = round(temperature, 1)
        humidity = round(humidity, 1)

        return temperature, humidity

    except ModbusException as e:
        print("Modbus异常:", e)
        return None, None
    except Exception as e:
        # 捕获除ModbusException之外的所有异常
        print(f"An error occurred: {e}")
        return None, None


def main():
    try:
        if client.connect():  
            temperature, humidity = read_temperature_and_humidity(client)
            if temperature is not None and humidity is not None:
                print(f"温度: {humidity}°C, 湿度: {temperature}%RH")
            client.close()  # 关闭连接
        else:
            print("无法连接到Modbus设备")
    except ConnectionException as e:
        print("连接异常:", e)


if __name__ == "__main__":
    main()

TCP版

from pymodbus.client.sync import ModbusTcpClient
from pymodbus.exceptions import ModbusException
import logging
logging.basicConfig()
log = logging.getLogger()
log.setLevel(logging.DEBUG)

# 远程Modbus服务器的IP地址和端口号
HOST = '192.168.1.250'
PORT = 8888

# 创建ModbusTcpClient实例，用于与Modbus服务器通信
client = ModbusTcpClient(HOST, port=PORT,ethod='rtu')

def read_holding_registers(unit, address, count):
    """
    从Modbus服务器读取保持寄存器的值。
    
    参数:
    unit (int): 从站ID（slave ID）
    address (int): 寄存器的起始地址
    count (int): 要读取的寄存器数量
    
    返回:
    list: 读取到的寄存器值列表
    """
    try:
        # 连接到Modbus服务器
        if client.connect():
            print(f"成功连接到Modbus服务器 {HOST}:{PORT}")
            
            # 读取保持寄存器
            response = client.read_holding_registers(address, count, unit=unit)
            
            # 检查是否成功接收到响应
            if not response.isError():
                print("读取寄存器成功")
                return response.registers
            else:
                print("读取寄存器失败")
                return None
        else:
            print("连接到Modbus服务器失败")
            return None
    except ModbusException as e:
        print(f"Modbus异常: {e}")
        return None
    finally:
        # 断开与Modbus服务器的连接
        client.close()

def calculate_temperature(raw_value):
    """
    根据传感器的数据格式计算实际温度值。
    
    参数:
    raw_value (int): 从传感器读取的原始温度值
    
    返回:
    float: 实际温度值
    """
    if raw_value > 32767:
        # 处理负温度值的补码
        return -((65536 - raw_value) / 10.0)
    else:
        return raw_value / 10.0

def calculate_humidity(raw_value):
    """
    根据传感器的数据格式计算实际湿度值。
    
    参数:
    raw_value (int): 从传感器读取的原始湿度值
    
    返回:
    float: 实际湿度值
    """
    return raw_value / 10.0

def main():
    # 从站ID，通常为1，除非您的设备配置不同
    slave_id = 1
    # 寄存器的起始地址，根据您的设备文档设置
    start_address = 0
    # 要读取的寄存器数量，根据您的需求设置
    number_of_registers = 2
    
    # 调用函数读取寄存器
    registers = read_holding_registers(slave_id, start_address, number_of_registers)
    
    # 打印读取到的寄存器值
    if registers is not None:
        # 计算温度和湿度
        temperature_raw = registers[0]
        humidity_raw = registers[1]
        
        temperature = calculate_temperature(temperature_raw)
        humidity = calculate_humidity(humidity_raw)
        
        print(f"读取到的温度值为: {humidity}℃")
        print(f"读取到的湿度值为: {temperature}%RH")

if __name__ == "__main__":
    main()