from pymodbus.client.sync import ModbusSerialClient as ModbusClient

from pymodbus.constants import Endian

from pymodbus.payload import BinaryPayloadDecoder, BinaryPayloadBuilder

import struct

def byteswap(byte16):

h = byte16 / 256

l = byte16 % 256

return l * 256 + h

def charswap(str2byte):

return str2byte[1] + str2byte[0]

client = ModbusClient(method='rtu', port='COM1', baudrate=9600, parity='N', stopbits=1, timeout=1.5, databits=8, unit=1)

client.connect()

endian=client.read_holding_registers(49991,4,unit=1)

#endian.registers[0] = byteswap(endian.registers[0])

#endian.registers[1] = byteswap(endian.registers[1])

#endian.registers[2] = byteswap(endian.registers[2])

#endian.registers[3] = byteswap(endian.registers[3])

decoder=BinaryPayloadDecoder.fromRegisters(endian.registers,endian=Endian.Big)

decoded={

'val':hex(decoder.decode_32bit_uint()),

'v100':decoder.decode_32bit_float()

}

print decoded

encoder = BinaryPayloadBuilder(endian=Endian.Big)

encoder.add_16bit_uint(0x1234)

buf = encoder.build()

#buf[0] = charswap(buf[0])

client.write_registers(51234, buf, unit=1, skip_encode=True)

encoder = BinaryPayloadBuilder(endian=Endian.Big)

encoder.add_32bit_float(1.0114)

encoder.add_32bit_float(-6)

buf = encoder.build()

#buf[0] = charswap(buf[0])

#buf[1] = charswap(buf[1])

#buf[2] = charswap(buf[2])

#buf[3] = charswap(buf[3])

client.write_registers(50000 + 8 * 5, buf, unit=1, skip_encode=True)

while True:

result = client.read_input_registers(100, 6, unit=1)

if result:

#result.registers[0] = byteswap(result.registers[0])

#result.registers[1] = byteswap(result.registers[1])

#result.registers[2] = byteswap(result.registers[2])

#result.registers[3] = byteswap(result.registers[3])

#result.registers[4] = byteswap(result.registers[4])

#result.registers[5] = byteswap(result.registers[5])

decoder = BinaryPayloadDecoder.fromRegisters(result.registers, endian=Endian.Big)

decoded = {

'voltage': decoder.decode_32bit_float(),

'pt100': decoder.decode_32bit_float(),

'freq': decoder.decode_32bit_float()

}

print decoded

client.write_coils(100, (1, 1, 1, 1, 1, 1), unit=1)

result = client.read_discrete_inputs(100, 4, unit=1)

print result.bits

encoder = BinaryPayloadBuilder(endian=Endian.Big)

encoder.add_32bit_float(20)

encoder.add_32bit_float(80)

buf = encoder.build()

#buf[0] = charswap(buf[0])

#buf[1] = charswap(buf[1])

#buf[2] = charswap(buf[2])

#buf[3] = charswap(buf[3])

client.write_registers(100, buf, unit=1, skip_encode=True)

#break