python 读写西门子PLC例子

client.py 存取 西门子PLC数据的客户端例子 

#!/usr/bin/env python
# -*- coding: utf-8 -*-

# Project: pi4b_aliyuniot
# File   : snap_client.py
# Author : Long.Xu <fangkailove@yeah.net>
#          http://gnolux.blog.csdn.net
#          QQ:26564303
# Time   : 2021/4/7 2:14 下午
# Copyright 2021 Long.Xu All rights Reserved. 

from snap7 import util, client
from snap7.types import S7AreaMK,S7AreaDB

my_plc = client.Client()
# my_plc.set_connection_type(3)

# -------------------------------------------
# plc rack and slot value table
# -------------------------------------------
# plc             rack            slot
# -------------------------------------------
# s7-200smart   0               1
# s7-300        0               2
# s7-400/WIN AC   见硬件组态       见硬件组态
# s7-1200/1500    0               0/1
# -------------------------------------------

my_plc.connect('127.0.0.1', rack=0, slot=1, tcpport=502)

byte_arrays = my_plc.read_area(area=S7AreaMK, dbnumber=0, start=0, size=2)
print('赋值前', util.get_bool(byte_arrays, 0, 0))
util.set_bool(byte_arrays, 0, 0, False)
my_plc.write_area(S7AreaMK, 0, 0, byte_arrays)
print('赋值后', util.get_bool(byte_arrays, 0, 0))
util.set_bool(byte_arrays, 1, 1, False)
my_plc.write_area(S7AreaMK, 2, 0, byte_arrays)

# DB区和200samart的V区,dbnumber 填 1, 其它填0
byte_arrays = my_plc.read_area(S7AreaDB, 1, 3222, 2)
print('赋值前', util.get_word(byte_arrays, 0))
util.set_word(byte_arrays, 0, 199)
my_plc.write_area(S7AreaDB, 1, 3222, byte_arrays)
print('赋值后', util.get_word(byte_arrays, 0))

my_plc.disconnect()
my_plc.destroy()

Server.py 模拟西门子plc 的例子
 

#!/usr/bin/env python
# -*- coding: utf-8 -*-

# Project: pi4b_aliyuniot
# File   : snap_server.py
# Author : Long.Xu <fangkailove@yeah.net>
#          http://gnolux.blog.csdn.net
#          QQ:26564303
# Time   : 2021/4/7 2:14 下午
# Copyright 2021 Long.Xu All rights Reserved. 

import time
import logging
import snap7

logger = logging.getLogger(__name__)


def mainloop(tcpport: int = 1102):
    server = snap7.server.Server()
    size = 999999
    DBdata = (snap7.types.wordlen_to_ctypes[snap7.types.S7WLByte] * size)()
    PAdata = (snap7.types.wordlen_to_ctypes[snap7.types.S7WLByte] * size)()
    TMdata = (snap7.types.wordlen_to_ctypes[snap7.types.S7WLByte] * size)()
    CTdata = (snap7.types.wordlen_to_ctypes[snap7.types.S7WLByte] * size)()
    MKdata = (snap7.types.wordlen_to_ctypes[snap7.types.S7WLByte] * size)()
    server.register_area(snap7.types.srvAreaDB, 1, DBdata)
    server.register_area(snap7.types.srvAreaPA, 1, PAdata)
    server.register_area(snap7.types.srvAreaTM, 1, TMdata)
    server.register_area(snap7.types.srvAreaCT, 1, CTdata)
    server.register_area(snap7.types.srvAreaMK, 1, MKdata)
    server.start(tcpport=tcpport)
    while True:
        while True:
            event = server.pick_event()
            if event:
                logger.info(server.event_text(event))
            else:
                break
        time.sleep(1)


mainloop(502)

西门子plc的读写，可以用 snap7库，参考官网： Snap7 Homepage