Modbus Register Definitions for the DAS Module

1. Serial Port Parameters

Physical Layer: TTL 5V   Baud Rate: 115200  Data Bits: 8   Parity Bit: None  Stop Bit: 1

2. Modbus Protocol

Modbus-RTU, Slave Address: 1

3. Register Definition

4. An example of reading data in Python.

main.py

import sys,os

sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), '..')))

from com import *


if __name__ == '__main__':
	device = read_config()
	print(device.to_string())


	#result = update_laser_config('edfa_current', 256)
	#if result != "":
	#    print("修改失败:", result)

com.py

import serial
from device import DeviceRegisters
#from config.config import global_config


select_cmd = bytearray([0x01, 0x03, 0x00, 0x00, 0x00, 0x16])

def calculate_crc(data):
    crc = 0xFFFF
    for pos in data:
        crc ^= pos
        for _ in range(8):
            if (crc & 1) != 0:
                crc >>= 1
                crc ^= 0xA001
            else:
                crc >>= 1
    return crc


def parse(response_data):
    data = response_data[3:-2]
    crc_received = response_data[-2:]
    crc_calculated = calculate_crc(response_data[:-2])
    crc_calculated_byte = crc_calculated.to_bytes(2, byteorder='little')

    # 检查 CRC 是否匹配
    if crc_received != crc_calculated_byte:
        print(f"CRC 校验失败，接收到的 CRC 为 {crc_received.hex()}，计算出的 CRC 为 {crc_calculated_byte.hex()}")
        return None
        
    device = DeviceRegisters()
    device.from_modbus_response(data)
    # print(device.to_string())

    return device

    
def connect():
    # 配置串行端口参数
    port ='/dev/ttyUSB0'
    baudrate = 115200
    data_bits = serial.EIGHTBITS
    parity = serial.PARITY_NONE
    stop_bits = serial.STOPBITS_ONE

    # 创建串行连接
    ser = serial.Serial(
        port=port,
        baudrate=baudrate,
        bytesize=data_bits,
        parity=parity,
        stopbits=stop_bits,
        timeout=1  # 设置读取超时时间（秒）
    )

    # 检查串行端口是否打开
    if ser.is_open:
        # print(f"串行端口 {port} 已打开.")
        return ser
    
    return None

def combo_cmd(command):
    crc = calculate_crc(command)
    command.append(crc & 0xFF)       # 低字节
    command.append((crc >> 8) & 0xFF) # 高字节

    # print(f"组合完成的数据: {command.hex()}")
    return command

def read_config():
    ser = connect()
    if ser is None:
        return False
    
    try:
        # 发送请求指令
        ser.write(combo_cmd(select_cmd.copy()))

        # 读取响应数据
        response_data = ser.read(49)  # 读取 47 字节（从站地址 + 功能码 + 数据字节数 + 44 字节数据 + 2 字节CRC）

        if len(response_data) < 49:
            print("响应数据长度不足，可能没有收到完整的数据。", response_data)

        # 关闭串行端口
        ser.close()
        # print(f"串行端口已关闭.")
    except Exception as e:
        print(f"发送或读取数据时出错: {e}")

    # 解析数据
    return parse(response_data)



def set_update_command(value, type):
    high_byte = (value >> 8) & 0xFF
    low_byte = value & 0xFF

    command = bytearray([])
    if type == 'edfa_current':
        command = bytearray([0x01, 0x06, 0x00, 0x01, high_byte, low_byte])
    elif type == 'voa1_voltage':
        command = bytearray([0x01, 0x06, 0x00, 0x09, high_byte, low_byte])
    elif type == 'voa2_voltage':
        command = bytearray([0x01, 0x06, 0x00, 0x0a, high_byte, low_byte])
    elif type == 'voa3_voltage':
        command = bytearray([0x01, 0x06, 0x00, 0x0b, high_byte, low_byte])
    else:
        return None
        
    return combo_cmd(command)


def update_laser_config(type, value):
    cmd = set_update_command(value, type)
    if cmd is None:
        return "不支持的参数"
   
    ser = connect()
    if ser is None:
        return "串口连接失败"

    n = ser.write(cmd)
    ser.close()

    if n <= 0:
        return "发送命令失败"
    
    print(type, "更新成功")

    return ""

device.py

class DeviceRegisters:
    def __init__(self):
        # EDFA开关，初始值为 0
        self.edfa_status = 0
        # EDFA电流设定值，初始值为 0
        self.edfa_current = 0
        # EDFA响应度，初始值为 0
        self.edfa_responsivity = 0
        # EDFA温度变化量，初始值为 0
        self.edfa_temperature = 0
        # EDFA出光功率，初始值为 0
        self.edfa_pump_power = 0
        # EDFA电流读取值，初始值为 0
        self.edfa_pump_current = 0

        # VOA电压值，初始值为 0
        self.voa1_voltage = 0
        self.voa2_voltage = 0
        self.voa3_voltage = 0
        # 模块温度值，初始值为 0
        self.module_temperature = 0

    def from_modbus_response(self, response_data):
        """
        从 Modbus 响应数据中解析值
        假设 response_data 已经去掉了从站地址、功能码和 CRC 校验码
        """
        self.edfa_status = (response_data[0] << 8) + response_data[1]
        self.edfa_current = (response_data[2] << 8) + response_data[3]
        self.edfa_responsivity = (response_data[4] << 8) + response_data[5]
        self.voa1_voltage = (response_data[18] << 8) + response_data[19]
        self.voa2_voltage = (response_data[20] << 8) + response_data[21]
        self.voa3_voltage = (response_data[22] << 8) + response_data[23]
        self.module_temperature = ((response_data[24] << 8) + response_data[25]) / 10
        # self.edfa_temperature = (response_data[14] << 8) + response_data[15]
        self.edfa_pump_power = (response_data[28] << 8) + response_data[29]
        self.edfa_pump_current = (response_data[30] << 8) + response_data[31]

    def to_string(self):
        """
        返回值的字符串表示
        """
        return (
            f"EDFA开关: {self.edfa_status}\n"
            f"EDFA电流设定值: {self.edfa_current}\n"
            f"EDFA响应度: {self.edfa_responsivity}\n"
            f"VOA1 电压值: {self.voa1_voltage}\n"
            f"VOA2 电压值: {self.voa2_voltage}\n"
            f"VOA3 电压值: {self.voa3_voltage}\n"
            f"模块温度: {self.module_temperature}\n"
            f"EDFA温度变化量: {self.edfa_temperature}\n"
            f"EDFA出光功率: {self.edfa_pump_power}\n"
            f"EDFA电流读取值: {self.edfa_pump_current}\n"
        )
    
    def as_dict(self):
        return self.__dict__

the value read

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