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#!/usr/bin/env python
"""
Pymodbus Asynchronous Client Examples
--------------------------------------------------------------------------
The following is an example of how to use the asynchronous serial modbus
client implementation from pymodbus using tornado.
"""
# ---------------------------------------------------------------------------#
# import needed libraries
# ---------------------------------------------------------------------------#
import functools
from tornado.ioloop import IOLoop
from pymodbus.client.asynchronous import schedulers
# ---------------------------------------------------------------------------#
# choose the requested modbus protocol
# ---------------------------------------------------------------------------#
from pymodbus.client.asynchronous.serial import AsyncModbusSerialClient
# ---------------------------------------------------------------------------#
# configure the client logging
# ---------------------------------------------------------------------------#
import logging
logging.basicConfig()
log = logging.getLogger()
log.setLevel(logging.DEBUG)
# ---------------------------------------------------------------------------#
# helper method to test deferred callbacks
# ---------------------------------------------------------------------------#
def dassert(future, callback):
def _assertor(value):
# by pass assertion, an error here stops the write callbacks
assert value
def on_done(f):
exc = f.exception()
if exc:
log.debug(exc)
return _assertor(False)
return _assertor(callback(f.result()))
future.add_done_callback(on_done)
def _print(value):
if hasattr(value, "bits"):
t = value.bits
elif hasattr(value, "registers"):
t = value.registers
else:
log.error(value)
return
log.info("Printing : -- {}".format(t))
return t
# ---------------------------------------------------------------------------#
# example requests
# ---------------------------------------------------------------------------#
# simply call the methods that you would like to use. An example session
# is displayed below along with some assert checks. Note that unlike the
# synchronous version of the client, the asynchronous version returns
# deferreds which can be thought of as a handle to the callback to send
# the result of the operation. We are handling the result using the
# deferred assert helper(dassert).
# ---------------------------------------------------------------------------#
UNIT = 0x01
def beginAsynchronousTest(client, protocol):
rq = client.write_coil(1, True, unit=UNIT)
rr = client.read_coils(1, 1, unit=UNIT)
dassert(rq, lambda r: r.function_code < 0x80) # test for no error
dassert(rr, _print) # test the expected value
rq = client.write_coils(1, [False]*8, unit=UNIT)
rr = client.read_coils(1, 8, unit=UNIT)
dassert(rq, lambda r: r.function_code < 0x80) # test for no error
dassert(rr, _print) # test the expected value
rq = client.write_coils(1, [False]*8, unit=UNIT)
rr = client.read_discrete_inputs(1, 8, unit=UNIT)
dassert(rq, lambda r: r.function_code < 0x80) # test for no error
dassert(rr, _print) # test the expected value
rq = client.write_register(1, 10, unit=UNIT)
rr = client.read_holding_registers(1, 1, unit=UNIT)
dassert(rq, lambda r: r.function_code < 0x80) # test for no error
dassert(rr, _print) # test the expected value
rq = client.write_registers(1, [10]*8, unit=UNIT)
rr = client.read_input_registers(1, 8, unit=UNIT)
dassert(rq, lambda r: r.function_code < 0x80) # test for no error
dassert(rr, _print) # test the expected value
arguments = {
'read_address': 1,
'read_count': 8,
'write_address': 1,
'write_registers': [20]*8,
}
rq = client.readwrite_registers(**arguments, unit=UNIT)
rr = client.read_input_registers(1,8, unit=UNIT)
dassert(rq, lambda r: r.registers == [20]*8) # test the expected value
dassert(rr, _print) # test the expected value
# -----------------------------------------------------------------------#
# close the client at some time later
# -----------------------------------------------------------------------#
IOLoop.current().add_timeout(IOLoop.current().time() + 1, client.close)
IOLoop.current().add_timeout(IOLoop.current().time() + 2, protocol.stop)
# ---------------------------------------------------------------------------#
# choose the client you want
# ---------------------------------------------------------------------------#
# make sure to start an implementation to hit against. For this
# you can use an existing device, the reference implementation in the tools
# directory, or start a pymodbus server.
# ---------------------------------------------------------------------------#
def err(*args, **kwargs):
log.error("Err", args, kwargs)
def callback(protocol, future):
log.debug("Client connected")
exp = future.exception()
if exp:
return err(exp)
client = future.result()
return beginAsynchronousTest(client, protocol)
if __name__ == "__main__":
# ----------------------------------------------------------------------- #
# Create temporary serial ports using SOCAT
# socat -d -d PTY,link=/tmp/ptyp0,raw,echo=0,ispeed=9600 PTY,
# link=/tmp/ttyp0,raw,echo=0,ospeed=9600
# Default framer is ModbusRtuFramer
# ----------------------------------------------------------------------- #
# Rtu
protocol, future = AsyncModbusSerialClient(schedulers.IO_LOOP,
method="rtu",
port="/dev/ptyp0",
baudrate=9600,
timeout=2)
# Asci
# from pymodbus.transaction import ModbusAsciiFramer
# protocol, future = AsyncModbusSerialClient(schedulers.IO_LOOP,
# method="ascii",
# port="/dev/ptyp0",
# framer=ModbusAsciiFramer,
# baudrate=9600,
# timeout=2)
# Binary
# from pymodbus.transaction import ModbusBinaryFramer
# protocol, future = AsyncModbusSerialClient(schedulers.IO_LOOP,
# method="binary",
# port="/dev/ptyp0",
# framer=ModbusBinaryFramer,
# baudrate=9600,
# timeout=2)
future.add_done_callback(functools.partial(callback, protocol))
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