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simulate_scale.py
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121 lines (97 loc) · 3.64 KB
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import math
import serial
import time
from mpmath import mp
# 模拟电子秤状态
scale_data = {
"net_weight": 70.15, # 净重
"gross_weight": 72.30, # 毛重
"tare_weight": 2.15 # 皮重
}
# 计算异或校验值
def calculate_xor(data):
xor_value = 0
for byte in data:
xor_value ^= byte
return xor_value
# 将异或校验值转换为ASCII字符
def xor_to_ascii(xor_value):
high_nibble = (xor_value >> 4) & 0x0F
low_nibble = xor_value & 0x0F
if high_nibble <= 9:
high_char = chr(high_nibble + ord('0'))
else:
high_char = chr(high_nibble + ord('7'))
if low_nibble <= 9:
low_char = chr(low_nibble + ord('0'))
else:
low_char = chr(low_nibble + ord('7'))
return high_char, low_char
# 构造响应数据帧
def build_response(address, command, value=None):
response = [0x02] # 开始符
response.append(ord(address)) # 地址编号
response.append(ord(command)) # 命令编号
if command == 'A': # 握手命令，无数据
pass
elif command in ['B', 'C', 'D']: # 读毛重、皮重、净重
sign = '+' if value >= 0 else '-' # 符号
weight = abs(value) * 100 # 将重量转换为整数形式（例如 70.15 -> 7015）
# 添加符号位
response.append(ord(sign))
# 生成6字节整数部分
weight_str = f"{int(weight):06d}" # 填充到6位
for char in weight_str:
response.append(ord(char))
# 添加小数点位置
decimal_position = 2 # 固定两位小数，表示小数点位于从右向左第2位
response.append(ord(str(decimal_position)))
# 异或校验
xor_value = calculate_xor(response[1:])
high_char, low_char = xor_to_ascii(xor_value)
response.append(ord(high_char))
response.append(ord(low_char))
response.append(0x03) # 结束符
return bytes(response)
# 模拟串口通信
def simulate_scale(port='COM1', baudrate=9600):
ser = serial.Serial(port, baudrate, timeout=1)
print(f"模拟电子秤已启动，监听端口 {port}...")
while True:
# 接收上位机命令
command = ser.read_until(b'\x03') # 读取直到结束符
if not command:
continue
print(f"接收到命令: {command.hex()}")
# 解析命令
try:
address = chr(command[1]) # 地址编号
cmd_type = chr(command[2]) # 命令类型
# 构造响应
if cmd_type == 'A': # 握手命令
response = build_response(address, 'A')
elif cmd_type == 'B': # 读毛重
response = build_response(address, 'B', scale_data["gross_weight"])
elif cmd_type == 'C': # 读皮重
response = build_response(address, 'C', scale_data["tare_weight"])
elif cmd_type == 'D': # 读净重
response = build_response(address, 'D', scale_data["net_weight"])
elif command[0] == 'S' and command[1] == 'I':
response = build_response(address, 'D', scale_data["net_weight"])
else:
print("未知命令")
continue
# 发送响应
ser.write(response)
print(f"发送响应: {response.hex()}")
except Exception as e:
print(f"处理命令时出错: {e}")
# 打印圆周率小数点后第501位到第505位
def pi_501():
mp.dps = 510 # 计算到小数点后510位
pi_str = str(mp.pi)[2:] # 去除"3."开头
print("第501-505位:", pi_str[500:505]) # 输出: 98336
# 启动模拟电子秤
if __name__ == "__main__":
simulate_scale()
# pi_501()