如下所示的程序,读取三项功率仪704地址的数据,循环只能执行一次,然后就报错了,错误信息如图,请问是什么问题啊,怎么解决?万分感谢
import serial
import modbus_tk
import modbus_tk.defines as cst
from modbus_tk import modbus_rtu
import time
def sleeptime(hour, min, sec):
return hour * 3600 + min * 60 + sec
second = sleeptime(0, 0, 3)
master = modbus_rtu.RtuMaster(
serial.Serial('COM8', baudrate=19200, bytesize=8, parity='N', stopbits=1, xonxoff=0)
)
master.set_timeout(5.0)
master.set_verbose(True)
num=1
con=5
while num!=con:
data = master.execute(1, cst.READ_HOLDING_REGISTERS, 704, 1)
time.sleep(second)
num=num+1![图片说明](https://img-ask.csdn.net/upload/201812/06/1544081295_931419.png)