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#!/usr/bin/env python
"""
Pymodbus Payload Building/Decoding Example
--------------------------------------------------------------------------
# Run modbus-payload-server.py or synchronous-server.py to check the behavior
"""
from pymodbus.constants import Endian
from pymodbus.payload import BinaryPayloadDecoder
from pymodbus.payload import BinaryPayloadBuilder
from pymodbus.client.sync import ModbusTcpClient as ModbusClient
from pymodbus.compat import iteritems
from collections import OrderedDict
# --------------------------------------------------------------------------- #
# configure the client logging
# --------------------------------------------------------------------------- #
import logging
FORMAT = ('%(asctime)-15s %(threadName)-15s'
' %(levelname)-8s %(module)-15s:%(lineno)-8s %(message)s')
logging.basicConfig(format=FORMAT)
log = logging.getLogger()
log.setLevel(logging.INFO)
def run_binary_payload_ex():
# ----------------------------------------------------------------------- #
# We are going to use a simple client to send our requests
# ----------------------------------------------------------------------- #
client = ModbusClient('127.0.0.1', port=5020)
client.connect()
# ----------------------------------------------------------------------- #
# If you need to build a complex message to send, you can use the payload
# builder to simplify the packing logic.
#
# Here we demonstrate packing a random payload layout, unpacked it looks
# like the following:
#
# - a 8 byte string 'abcdefgh'
# - a 32 bit float 22.34
# - a 16 bit unsigned int 0x1234
# - another 16 bit unsigned int 0x5678
# - an 8 bit int 0x12
# - an 8 bit bitstring [0,1,0,1,1,0,1,0]
# - an 32 bit uint 0x12345678
# - an 32 bit signed int -0x1234
# - an 64 bit signed int 0x12345678
# The packing can also be applied to the word (wordorder) and bytes in each
# word (byteorder)
# The wordorder is applicable only for 32 and 64 bit values
# Lets say we need to write a value 0x12345678 to a 32 bit register
# The following combinations could be used to write the register
# +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ #
# Word Order - Big Byte Order - Big
# word1 =0x1234 word2 = 0x5678
# Word Order - Big Byte Order - Little
# word1 =0x3412 word2 = 0x7856
# Word Order - Little Byte Order - Big
# word1 = 0x5678 word2 = 0x1234
# Word Order - Little Byte Order - Little
# word1 =0x7856 word2 = 0x3412
# +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ #
# ----------------------------------------------------------------------- #
builder = BinaryPayloadBuilder(byteorder=Endian.Big,
wordorder=Endian.Little)
builder.add_string('abcdefgh')
builder.add_bits([0, 1, 0, 1, 1, 0, 1, 0])
builder.add_8bit_int(-0x12)
builder.add_8bit_uint(0x12)
builder.add_16bit_int(-0x5678)
builder.add_16bit_uint(0x1234)
builder.add_32bit_int(-0x1234)
builder.add_32bit_uint(0x12345678)
builder.add_32bit_float(22.34)
builder.add_32bit_float(-22.34)
builder.add_64bit_int(-0xDEADBEEF)
builder.add_64bit_uint(0x12345678DEADBEEF)
builder.add_64bit_uint(0x12345678DEADBEEF)
builder.add_64bit_float(123.45)
builder.add_64bit_float(-123.45)
payload = builder.to_registers()
print("-" * 60)
print("Writing Registers")
print("-" * 60)
print(payload)
print("\n")
payload = builder.build()
address = 0
# Can write registers
# registers = builder.to_registers()
# client.write_registers(address, registers, unit=1)
# Or can write encoded binary string
client.write_registers(address, payload, skip_encode=True, unit=1)
# ----------------------------------------------------------------------- #
# If you need to decode a collection of registers in a weird layout, the
# payload decoder can help you as well.
#
# Here we demonstrate decoding a random register layout, unpacked it looks
# like the following:
#
# - a 8 byte string 'abcdefgh'
# - a 32 bit float 22.34
# - a 16 bit unsigned int 0x1234
# - another 16 bit unsigned int which we will ignore
# - an 8 bit int 0x12
# - an 8 bit bitstring [0,1,0,1,1,0,1,0]
# ----------------------------------------------------------------------- #
address = 0x0
count = len(payload)
result = client.read_holding_registers(address, count, unit=1)
print("-" * 60)
print("Registers")
print("-" * 60)
print(result.registers)
print("\n")
decoder = BinaryPayloadDecoder.fromRegisters(result.registers,
byteorder=Endian.Little,
wordorder=Endian.Little)
decoded = OrderedDict([
('string', decoder.decode_string(8)),
('bits', decoder.decode_bits()),
('8int', decoder.decode_8bit_int()),
('8uint', decoder.decode_8bit_uint()),
('16int', decoder.decode_16bit_int()),
('16uint', decoder.decode_16bit_uint()),
('32int', decoder.decode_32bit_int()),
('32uint', decoder.decode_32bit_uint()),
('32float', decoder.decode_32bit_float()),
('32float2', decoder.decode_32bit_float()),
('64int', decoder.decode_64bit_int()),
('64uint', decoder.decode_64bit_uint()),
('ignore', decoder.skip_bytes(8)),
('64float', decoder.decode_64bit_float()),
('64float2', decoder.decode_64bit_float()),
])
print("-" * 60)
print("Decoded Data")
print("-" * 60)
for name, value in iteritems(decoded):
print("%s\t" % name, hex(value) if isinstance(value, int) else value)
# ----------------------------------------------------------------------- #
# close the client
# ----------------------------------------------------------------------- #
client.close()
if __name__ == "__main__":
run_binary_payload_ex()
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