1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
|
#!/usr/bin/env python
"""
Pymodbus Asynchronous Client Examples
--------------------------------------------------------------------------
The following is an example of how to use the asynchronous modbus
client implementation from pymodbus using Tornado.
"""
import functools
from tornado.ioloop import IOLoop
from pymodbus.client.asynchronous import schedulers
# ---------------------------------------------------------------------------#
# choose the requested modbus protocol
# ---------------------------------------------------------------------------#
# from pymodbus.client.asynchronous.udp import AsyncModbusUDPClient as ModbusClient
from pymodbus.client.asynchronous.tcp import AsyncModbusTCPClient as ModbusClient
# ---------------------------------------------------------------------------#
# 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
UNIT = 0x01
# ---------------------------------------------------------------------------#
# 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).
# ---------------------------------------------------------------------------#
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__":
protocol, future = ModbusClient(schedulers.IO_LOOP, port=5020)
future.add_done_callback(functools.partial(callback, protocol))
|
