按照这个例子，我有一个正在运行的 ModbusRTU 服务器。我知道如何更新上下文，但我无法更新正在运行的服务器的上下文。
当我更新 run_updating_server() 函数中的上下文时（在 StartSerialServer() 之前），它工作正常。但是当我尝试通过调用 update_writer(context) 来更新运行上下文时，它不会更新。
从 withingupdate_writer() 调用我自己的函数 'getUpdatedContext()' 也不起作用：
def updating_writer(a):
a =(getContext(),)
""" A worker process that runs every so often and
updates live values of the context. It should be noted
that there is a race condition for the update.
:param arguments: The input arguments to the call
"""
log.debug("updating the context")
context = a[0]
register = 3
slave_id = 0x41
address = 0x10
values = context[slave_id].getValues(register, address, count=5)
values = [v + 1 for v in values]
log.debug("new values: " + str(values))
context[slave_id].setValues(register, address, values)
获取上下文（）：
def getContext():
store = ModbusSlaveContext(
di=ModbusSequentialDataBlock(0, [17]*100),
co=ModbusSequentialDataBlock(0, [17]*100),
hr=ModbusSequentialDataBlock(0, [17]*100),
ir=ModbusSequentialDataBlock(0, [17]*100))
store.setValues(5, 1, [0])
context = ModbusServerContext(slaves=store, single=True)
return context
我的完整代码：
#!/usr/bin/env python
import os
import sys
"""
Pymodbus Server With Updating Thread
--------------------------------------------------------------------------
This is an example of having a background thread updating the
context while the server is operating. This can also be done with
a python thread::
from threading import Thread
thread = Thread(target=updating_writer, args=(context,))
thread.start()
"""
# --------------------------------------------------------------------------- #
# import the modbus libraries we need
# --------------------------------------------------------------------------- #
from pymodbus.server.asynchronous import StartSerialServer
from pymodbus.device import ModbusDeviceIdentification
from pymodbus.datastore import ModbusSequentialDataBlock
from pymodbus.datastore import ModbusSlaveContext, ModbusServerContext
from pymodbus.transaction import ModbusRtuFramer, ModbusAsciiFramer
# --------------------------------------------------------------------------- #
# import the twisted libraries we need
# --------------------------------------------------------------------------- #
from twisted.internet.task import LoopingCall
# --------------------------------------------------------------------------- #
# configure the service logging
# --------------------------------------------------------------------------- #
import logging
logging.basicConfig()
log = logging.getLogger()
log.setLevel(logging.DEBUG)
# --------------------------------------------------------------------------- #
# define your callback process
# --------------------------------------------------------------------------- #
def updating_writer(a):
""" A worker process that runs every so often and
updates live values of the context. It should be noted
that there is a race condition for the update.
:param arguments: The input arguments to the call
"""
log.debug("updating the context")
context = a[0]
register = 3
slave_id = 0x41
address = 0x10
values = context[slave_id].getValues(register, address, count=5)
values = [v + 1 for v in values]
log.debug("new values: " + str(values))
context[slave_id].setValues(register, address, values)
def run_updating_server():
# ----------------------------------------------------------------------- #
# initialize your data store
# ----------------------------------------------------------------------- #
store = ModbusSlaveContext(
di=ModbusSequentialDataBlock(0, [17]*100),
co=ModbusSequentialDataBlock(0, [17]*100),
hr=ModbusSequentialDataBlock(0, [17]*100),
ir=ModbusSequentialDataBlock(0, [17]*100))
context = ModbusServerContext(slaves=store, single=True)
# ----------------------------------------------------------------------- #
# initialize the server information
# ----------------------------------------------------------------------- #
identity = ModbusDeviceIdentification()
identity.VendorName = 'pymodbus'
identity.ProductCode = 'PM'
identity.VendorUrl = 'http://github.com/bashwork/pymodbus/'
identity.ProductName = 'pymodbus Server'
identity.ModelName = 'pymodbus Server'
identity.MajorMinorRevision = '2.2.0'
# ----------------------------------------------------------------------- #
# run the server you want
# ----------------------------------------------------------------------- #
time = 5
loop = LoopingCall(f=updating_writer, a=(context,))
loop.start(time, now=False) # initially delay by time
log.debug("::: Starting Modbus RTU server :::")
# RTU:
StartSerialServer(context, framer=ModbusRtuFramer, identity=identity,
port='/dev/ttyUSB0',
timeout=2,
baudrate=115200,
parity='E',
bytesize=8,
stopbits=1)
def main():
pid = str(os.getpid())
filename = 'modbusUpdatingServer.pid'
pidfile = str(os.getcwd()) + '/' + filename
if os.path.isfile(pidfile):
print (filename + " already exists \n exiting")
sys.exit()
open(pidfile, 'w').write(pid)
try:
# run server
run_updating_server()
finally:
os.unlink(pidfile)
if __name__ == "__main__":
main()
我想从另一个 python 脚本更新上下文，我试过：
从该“其他python脚本”调用updated_writer(a)，其中a = updatedContext。
从withingupdate_writer(a)调用getUpdatedContext()，这是“那个其他python脚本”中的一个函数，它返回updatedContext
使上下文全局化，添加一个函数 updateContext(a)，从另一个 python 脚本调用该函数。
这一切都导致编译代码，但运行服务器的上下文没有得到更新。
这里是来自“其他python脚本”的代码：
from pymodbus.datastore import ModbusSequentialDataBlock, ModbusSlaveContext, ModbusServerContext
from threading import Thread
import os
import subprocess
import sys
from modbusUpdatingServer import updating_writer, run_updating_server
def writeUpdatedContext():
store = ModbusSlaveContext(
di=ModbusSequentialDataBlock(0, [17]*100),
co=ModbusSequentialDataBlock(0, [17]*100),
hr=ModbusSequentialDataBlock(0, [17]*100),
ir=ModbusSequentialDataBlock(0, [17]*100))
store.setValues(5, 1, [0])
context = ModbusServerContext(slaves=store, single=True)
updating_writer(a=(context,)
def main():
choice = input("press x if you want to update the context")
if choice == 'x' or choice == 'X':
writeUpdatedContext()
if __name__ == "__main__":
main()
我应该如何与updated_writer交互？我想要实现的是我的 modbusRTU 服务器正在运行，并从另一个威胁中更新上下文，所以我的 modbus 客户端（主）可以读取我填写的寄存器。