利用ModbusTcpClient库在三菱PLC上进行通讯读字

Question

我试图使用以下代码在三菱PLC (Q06udeh)上进行通信和阅读：

from pymodbus.client.sync import ModbusTcpClient

client = ModbusTcpClient('10.1.1.4',port=5007)
client.connect()

result = client.read_holding_registers(1,1)
print result
t = result.registers[0]
print t

我得到的输出如下：

None

Traceback (most recent call last):
  File "C:\Users\serkan\Desktop\sasda.py", line 8, in <module>
    t = result.registers[0]
 AttributeError: 'NoneType' object has no attribute 'registers'

无论我如何改变不同参数的访问词没有希望，我仍然没有成功。

请帮帮忙。

Answer 1

使用modbus_tk

首先，您需要安装modbus_tk包：

pip install modbus_tk

然后，尝试运行以下示例代码：

#  General MODBUS includes
import modbus_tk
import modbus_tk.defines as cst
# TCP MODBUS includes
from modbus_tk import modbus_tcp

def main():
    device_id = 1
    master = modbus_tcp.TcpMaster("10.1.1.4")
    master.set_timeout(3)     #it's really optional
    master.set_verbose(True)  # this is optional too
    data = master.execute(device_id, cst.READ_HOLDING_REGISTERS, 100, 1) #Usage: 100 is registry number and 1 means that size of data is 16bit (modbus protocol specification)
    print "data    ", data
    print "data[0] ", data[0]

if __name__ == "__main__":
    main()

您可以在这里找到更多的示例：https://github.com/ljean/modbus-tk/tree/master/examples