Modbus Message Generator Example

This is an example of a utility that will build examples of modbus messages in all the available formats in the pymodbus package.

Program Source

#!/usr/bin/env python
'''
Modbus Message Generator
--------------------------------------------------------------------------

The following is an example of how to generate example encoded messages
for the supplied modbus format:

* tcp    - `./generate-messages.py -f tcp -m rx -b`
* ascii  - `./generate-messages.py -f ascii -m tx -a`
* rtu    - `./generate-messages.py -f rtu -m rx -b`
* binary - `./generate-messages.py -f binary -m tx -b`
'''
from optparse import OptionParser
#--------------------------------------------------------------------------#
# import all the available framers
#--------------------------------------------------------------------------#
from pymodbus.transaction import ModbusSocketFramer
from pymodbus.transaction import ModbusBinaryFramer
from pymodbus.transaction import ModbusAsciiFramer
from pymodbus.transaction import ModbusRtuFramer
#--------------------------------------------------------------------------#
# import all available messages
#--------------------------------------------------------------------------#
from pymodbus.bit_read_message import *
from pymodbus.bit_write_message import *
from pymodbus.diag_message import *
from pymodbus.file_message import *
from pymodbus.other_message import *
from pymodbus.mei_message import *
from pymodbus.register_read_message import *
from pymodbus.register_write_message import *

#--------------------------------------------------------------------------#
# initialize logging
#--------------------------------------------------------------------------#
import logging
modbus_log = logging.getLogger("pymodbus")


#--------------------------------------------------------------------------#
# enumerate all request messages
#--------------------------------------------------------------------------#
_request_messages = [
    ReadHoldingRegistersRequest,
    ReadDiscreteInputsRequest,
    ReadInputRegistersRequest,
    ReadCoilsRequest,
    WriteMultipleCoilsRequest,
    WriteMultipleRegistersRequest,
    WriteSingleRegisterRequest,
    WriteSingleCoilRequest,
    ReadWriteMultipleRegistersRequest,
    
    ReadExceptionStatusRequest,
    GetCommEventCounterRequest,
    GetCommEventLogRequest,
    ReportSlaveIdRequest,
    
    ReadFileRecordRequest,
    WriteFileRecordRequest,
    MaskWriteRegisterRequest,
    ReadFifoQueueRequest,
    
    ReadDeviceInformationRequest,

    ReturnQueryDataRequest,
    RestartCommunicationsOptionRequest,
    ReturnDiagnosticRegisterRequest,
    ChangeAsciiInputDelimiterRequest,
    ForceListenOnlyModeRequest,
    ClearCountersRequest,
    ReturnBusMessageCountRequest,
    ReturnBusCommunicationErrorCountRequest,
    ReturnBusExceptionErrorCountRequest,
    ReturnSlaveMessageCountRequest,
    ReturnSlaveNoResponseCountRequest,
    ReturnSlaveNAKCountRequest,
    ReturnSlaveBusyCountRequest,
    ReturnSlaveBusCharacterOverrunCountRequest,
    ReturnIopOverrunCountRequest,
    ClearOverrunCountRequest,
    GetClearModbusPlusRequest,
]


#--------------------------------------------------------------------------#
# enumerate all response messages
#--------------------------------------------------------------------------#
_response_messages = [
    ReadHoldingRegistersResponse,
    ReadDiscreteInputsResponse,
    ReadInputRegistersResponse,
    ReadCoilsResponse,
    WriteMultipleCoilsResponse,
    WriteMultipleRegistersResponse,
    WriteSingleRegisterResponse,
    WriteSingleCoilResponse,
    ReadWriteMultipleRegistersResponse,
    
    ReadExceptionStatusResponse,
    GetCommEventCounterResponse,
    GetCommEventLogResponse,
    ReportSlaveIdResponse,

    ReadFileRecordResponse,
    WriteFileRecordResponse,
    MaskWriteRegisterResponse,
    ReadFifoQueueResponse,

    ReadDeviceInformationResponse,

    ReturnQueryDataResponse,
    RestartCommunicationsOptionResponse,
    ReturnDiagnosticRegisterResponse,
    ChangeAsciiInputDelimiterResponse,
    ForceListenOnlyModeResponse,
    ClearCountersResponse,
    ReturnBusMessageCountResponse,
    ReturnBusCommunicationErrorCountResponse,
    ReturnBusExceptionErrorCountResponse,
    ReturnSlaveMessageCountResponse,
    ReturnSlaveNoReponseCountResponse,
    ReturnSlaveNAKCountResponse,
    ReturnSlaveBusyCountResponse,
    ReturnSlaveBusCharacterOverrunCountResponse,
    ReturnIopOverrunCountResponse,
    ClearOverrunCountResponse,
    GetClearModbusPlusResponse,
]


#--------------------------------------------------------------------------#
# build an arguments singleton
#--------------------------------------------------------------------------#
# Feel free to override any values here to generate a specific message
# in question. It should be noted that many argument names are reused
# between different messages, and a number of messages are simply using
# their default values.
#--------------------------------------------------------------------------#
_arguments = {
    'address'           : 0x12,
    'count'             : 0x08,
    'value'             : 0x01,
    'values'            : [0x01] * 8,
    'read_address'      : 0x12,
    'read_count'        : 0x08,
    'write_address  '   : 0x12,
    'write_registers'   : [0x01] * 8,
    'transaction'       : 0x01,
    'protocol'          : 0x00,
    'unit'              : 0x01,
}


#---------------------------------------------------------------------------# 
# generate all the requested messages
#---------------------------------------------------------------------------# 
def generate_messages(framer, options):
    ''' A helper method to parse the command line options

    :param framer: The framer to encode the messages with
    :param options: The message options to use
    '''
    messages = _request_messages if options.messages == 'tx' else _response_messages
    for message in messages:
        message = message(**_arguments)
        print "%-44s = " % message.__class__.__name__,
        packet = framer.buildPacket(message)
        if not options.ascii:
            packet = packet.encode('hex') + '\n'
        print packet,   # because ascii ends with a \r\n


#---------------------------------------------------------------------------# 
# initialize our program settings
#---------------------------------------------------------------------------# 
def get_options():
    ''' A helper method to parse the command line options

    :returns: The options manager
    '''
    parser = OptionParser()

    parser.add_option("-f", "--framer",
        help="The type of framer to use (tcp, rtu, binary, ascii)",
        dest="framer", default="tcp")

    parser.add_option("-D", "--debug",
        help="Enable debug tracing",
        action="store_true", dest="debug", default=False)

    parser.add_option("-a", "--ascii",
        help="The indicates that the message is ascii",
        action="store_true", dest="ascii", default=True)

    parser.add_option("-b", "--binary",
        help="The indicates that the message is binary",
        action="store_false", dest="ascii")

    parser.add_option("-m", "--messages",
        help="The messages to encode (rx, tx)",
        dest="messages", default='rx')

    (opt, arg) = parser.parse_args()
    return opt

def main():
    ''' The main runner function
    '''
    option = get_options()

    if option.debug:
        try:
            modbus_log.setLevel(logging.DEBUG)
    	    logging.basicConfig()
        except Exception, e:
    	    print "Logging is not supported on this system"

    framer = lookup = {
        'tcp':    ModbusSocketFramer,
        'rtu':    ModbusRtuFramer,
        'binary': ModbusBinaryFramer,
        'ascii':  ModbusAsciiFramer,
    }.get(option.framer, ModbusSocketFramer)(None)

    generate_messages(framer, option)

if __name__ == "__main__":
    main()

Example Request Messages

# ------------------------------------------------------------
# What follows is a collection of encoded messages that can
# be used to test the message-parser.  Simply uncomment the
# messages you want decoded and run the message parser with
# the given arguments. What follows is the listing of messages
# that are encoded in each format:
#
# - ReadHoldingRegistersRequest
# - ReadDiscreteInputsRequest
# - ReadInputRegistersRequest
# - ReadCoilsRequest
# - WriteMultipleCoilsRequest
# - WriteMultipleRegistersRequest
# - WriteSingleRegisterRequest
# - WriteSingleCoilRequest
# - ReadWriteMultipleRegistersRequest
# - ReadExceptionStatusRequest
# - GetCommEventCounterRequest
# - GetCommEventLogRequest
# - ReportSlaveIdRequest
# - ReadFileRecordRequest
# - WriteFileRecordRequest
# - MaskWriteRegisterRequest
# - ReadFifoQueueRequest
# - ReadDeviceInformationRequest
# - ReturnQueryDataRequest
# - RestartCommunicationsOptionRequest
# - ReturnDiagnosticRegisterRequest
# - ChangeAsciiInputDelimiterRequest
# - ForceListenOnlyModeRequest
# - ClearCountersRequest
# - ReturnBusMessageCountRequest
# - ReturnBusCommunicationErrorCountRequest
# - ReturnBusExceptionErrorCountRequest
# - ReturnSlaveMessageCountRequest
# - ReturnSlaveNoReponseCountRequest
# - ReturnSlaveNAKCountRequest
# - ReturnSlaveBusyCountRequest
# - ReturnSlaveBusCharacterOverrunCountRequest
# - ReturnIopOverrunCountRequest
# - ClearOverrunCountRequest
# - GetClearModbusPlusRequest
# ------------------------------------------------------------
# Modbus TCP Messages
# ------------------------------------------------------------
# [         MBAP Header         ] [ Function Code] [ Data ]
# [ tid ][ pid ][ length ][ uid ]
#   2b     2b     2b        1b           1b           Nb
#
# ./message-parser -b -p tcp -f messages
# ------------------------------------------------------------
#000100000006010300120008
#000100000006010200120008
#000100000006010400120008
#000100000006010100120008
#000100000008010f0012000801ff
#0001000000170110001200081000010001000100010001000100010001
#000100000006010600120001
#00010000000601050012ff00
#00010000001b011700120008000000081000010001000100010001000100010001
#0001000000020107
#000100000002010b
#000100000002010c
#0001000000020111
#000100000003011400
#000100000003011500
#00010000000801160012ffff0000
#00010000000401180012
#000100000005012b0e0100
#000100000006010800000000
#000100000006010800010000
#000100000006010800020000
#000100000006010800030000
#000100000006010800040000
#0001000000060108000a0000
#0001000000060108000b0000
#0001000000060108000c0000
#0001000000060108000d0000
#0001000000060108000e0000
#0001000000060108000f0000
#000100000006010800100000
#000100000006010800110000
#000100000006010800120000
#000100000006010800130000
#000100000006010800140000
#000100000006010800150000
# ------------------------------------------------------------
# Modbus RTU Messages
# ------------------------------------------------------------
# [Address ][ Function Code] [ Data ][ CRC ]
#  1b         1b               Nb      2b   
#
# ./message-parser -b -p rtu -f messages
# ------------------------------------------------------------
#010300120008e409
#010200120008d9c9
#01040012000851c9
#0101001200089dc9
#010f0012000801ff06d6
#0110001200081000010001000100010001000100010001d551
#010600120001e80f
#01050012ff002c3f
#011700120008000000081000010001000100010001000100010001e6f8
#010741e2
#010b41e7
#010c0025
#0111c02c
#0114002f00
#0115002e90
#01160012ffff00004e21
#0118001201d2
#012b0e01007077
#010800000000e00b
#010800010000b1cb
#01080002000041cb
#010800030000100b
#010800040000a1ca
#0108000a0000c009
#0108000b000091c9
#0108000c00002008
#0108000d000071c8
#0108000e000081c8
#0108000f0000d008
#010800100000e1ce
#010800110000b00e
#010800120000400e
#01080013000011ce
#010800140000a00f
#010800150000f1cf
# ------------------------------------------------------------
# Modbus ASCII Messages
# ------------------------------------------------------------
# [ Start ][Address ][ Function ][ Data ][ LRC ][ End ]
#   1c        2c         2c         Nc     2c      2c
#
# ./message-parser -a -p ascii -f messages
# ------------------------------------------------------------
#:010300120008E2
#:010200120008E3
#:010400120008E1
#:010100120008E4
#:010F0012000801FFD6
#:0110001200081000010001000100010001000100010001BD
#:010600120001E6
#:01050012FF00E9
#:011700120008000000081000010001000100010001000100010001AE
#:0107F8
#:010BF4
#:010CF3
#:0111EE
#:011400EB
#:011500EA
#:01160012FFFF0000D9
#:01180012D5
#:012B0E0100C5
#:010800000000F7
#:010800010000F6
#:010800020000F5
#:010800030000F4
#:010800040000F3
#:0108000A0000ED
#:0108000B0000EC
#:0108000C0000EB
#:0108000D0000EA
#:0108000E0000E9
#:0108000F0000E8
#:010800100000E7
#:010800110000E6
#:010800120000E5
#:010800130000E4
#:010800140000E3
#:010800150000E2
# ------------------------------------------------------------
# Modbus Binary Messages
# ------------------------------------------------------------
# [ Start ][Address ][ Function ][ Data ][ CRC ][ End ]
#   1b        1b         1b         Nb     2b     1b
#
# ./message-parser -b -p binary -f messages
# ------------------------------------------------------------
#7b010300120008e4097d
#7b010200120008d9c97d
#7b01040012000851c97d
#7b0101001200089dc97d
#7b010f0012000801ff06d67d
#7b0110001200081000010001000100010001000100010001d5517d
#7b010600120001e80f7d
#7b01050012ff002c3f7d
#7b011700120008000000081000010001000100010001000100010001e6f87d
#7b010741e27d
#7b010b41e77d
#7b010c00257d
#7b0111c02c7d
#7b0114002f007d
#7b0115002e907d
#7b01160012ffff00004e217d
#7b0118001201d27d
#7b012b0e010070777d
#7b010800000000e00b7d
#7b010800010000b1cb7d
#7b01080002000041cb7d
#7b010800030000100b7d
#7b010800040000a1ca7d
#7b0108000a0000c0097d
#7b0108000b000091c97d
#7b0108000c000020087d
#7b0108000d000071c87d
#7b0108000e000081c87d
#7b0108000f0000d0087d
#7b010800100000e1ce7d
#7b010800110000b00e7d
#7b010800120000400e7d
#7b01080013000011ce7d
#7b010800140000a00f7d
#7b010800150000f1cf7d

Example Response Messages

# ------------------------------------------------------------
# What follows is a collection of encoded messages that can
# be used to test the message-parser.  Simply uncomment the
# messages you want decoded and run the message parser with
# the given arguments. What follows is the listing of messages
# that are encoded in each format:
#
# - ReadHoldingRegistersResponse
# - ReadDiscreteInputsResponse
# - ReadInputRegistersResponse
# - ReadCoilsResponse
# - WriteMultipleCoilsResponse
# - WriteMultipleRegistersResponse
# - WriteSingleRegisterResponse
# - WriteSingleCoilResponse
# - ReadWriteMultipleRegistersResponse
# - ReadExceptionStatusResponse
# - GetCommEventCounterResponse
# - GetCommEventLogResponse
# - ReportSlaveIdResponse
# - ReadFileRecordResponse
# - WriteFileRecordResponse
# - MaskWriteRegisterResponse
# - ReadFifoQueueResponse
# - ReadDeviceInformationResponse
# - ReturnQueryDataResponse
# - RestartCommunicationsOptionResponse
# - ReturnDiagnosticRegisterResponse
# - ChangeAsciiInputDelimiterResponse
# - ForceListenOnlyModeResponse
# - ClearCountersResponse
# - ReturnBusMessageCountResponse
# - ReturnBusCommunicationErrorCountResponse
# - ReturnBusExceptionErrorCountResponse
# - ReturnSlaveMessageCountResponse
# - ReturnSlaveNoReponseCountResponse
# - ReturnSlaveNAKCountResponse
# - ReturnSlaveBusyCountResponse
# - ReturnSlaveBusCharacterOverrunCountResponse
# - ReturnIopOverrunCountResponse
# - ClearOverrunCountResponse
# - GetClearModbusPlusResponse
# ------------------------------------------------------------
# Modbus TCP Messages
# ------------------------------------------------------------
# [         MBAP Header         ] [ Function Code] [ Data ]
# [ tid ][ pid ][ length ][ uid ]
#   2b     2b     2b        1b           1b           Nb
#
# ./message-parser -b -p tcp -f messages
# ------------------------------------------------------------
#00010000001301031000010001000100010001000100010001
#000100000004010201ff
#00010000001301041000010001000100010001000100010001
#000100000004010101ff
#000100000006010f00120008
#000100000006011000120008
#000100000006010600120001
#00010000000601050012ff00
#00010000001301171000010001000100010001000100010001
#000100000003010700
#000100000006010b00000008
#000100000009010c06000000000000
#00010000000501110300ff
#000100000003011400
#000100000003011500
#00010000000801160012ffff0000
#00010000001601180012001000010001000100010001000100010001
#000100000008012b0e0183000000
#000100000006010800000000
#000100000006010800010000
#000100000006010800020000
#000100000006010800030000
#00010000000401080004
#0001000000060108000a0000
#0001000000060108000b0000
#0001000000060108000c0000
#0001000000060108000d0000
#0001000000060108000e0000
#0001000000060108000f0000
#000100000006010800100000
#000100000006010800110000
#000100000006010800120000
#000100000006010800130000
#000100000006010800140000
#000100000006010800150000
# ------------------------------------------------------------
# Modbus RTU Messages
# ------------------------------------------------------------
# [Address ][ Function Code] [ Data ][ CRC ]
#  1b         1b               Nb      2b   
#
# ./message-parser -b -p rtu -f messages
# ------------------------------------------------------------
#0103100001000100010001000100010001000193b4
#010201ffe1c8
#0104100001000100010001000100010001000122c1
#010101ff11c8
#010f00120008f408
#01100012000861ca
#010600120001e80f
#01050012ff002c3f
#01171000010001000100010001000100010001d640
#0107002230
#010b00000008a5cd
#010c060000000000006135
#01110300ffacbc
#0114002f00
#0115002e90
#01160012ffff00004e21
#01180012001000010001000100010001000100010001d74d
#012b0e01830000000faf
#010800000000e00b
#010800010000b1cb
#01080002000041cb
#010800030000100b
#0108000481d9
#0108000a0000c009
#0108000b000091c9
#0108000c00002008
#0108000d000071c8
#0108000e000081c8
#0108000f0000d008
#010800100000e1ce
#010800110000b00e
#010800120000400e
#01080013000011ce
#010800140000a00f
#010800150000f1cf
# ------------------------------------------------------------
# Modbus ASCII Messages
# ------------------------------------------------------------
# [ Start ][Address ][ Function ][ Data ][ LRC ][ End ]
#   1c        2c         2c         Nc     2c      2c
#
# ./message-parser -a -p ascii -f messages
# ------------------------------------------------------------
#:01031000010001000100010001000100010001E4
#:010201FFFD
#:01041000010001000100010001000100010001E3
#:010101FFFE
#:010F00120008D6
#:011000120008D5
#:010600120001E6
#:01050012FF00E9
#:01171000010001000100010001000100010001D0
#:010700F8
#:010B00000008EC
#:010C06000000000000ED
#:01110300FFEC
#:011400EB
#:011500EA
#:01160012FFFF0000D9
#:01180012001000010001000100010001000100010001BD
#:012B0E018300000042
#:010800000000F7
#:010800010000F6
#:010800020000F5
#:010800030000F4
#:01080004F3
#:0108000A0000ED
#:0108000B0000EC
#:0108000C0000EB
#:0108000D0000EA
#:0108000E0000E9
#:0108000F0000E8
#:010800100000E7
#:010800110000E6
#:010800120000E5
#:010800130000E4
#:010800140000E3
#:010800150000E2
# ------------------------------------------------------------
# Modbus Binary Messages
# ------------------------------------------------------------
# [ Start ][Address ][ Function ][ Data ][ CRC ][ End ]
#   1b        1b         1b         Nb     2b     1b
#
# ./message-parser -b -p binary -f messages
# ------------------------------------------------------------
#7b0103100001000100010001000100010001000193b47d
#7b010201ffe1c87d
#7b0104100001000100010001000100010001000122c17d
#7b010101ff11c87d
#7b010f00120008f4087d
#7b01100012000861ca7d
#7b010600120001e80f7d
#7b01050012ff002c3f7d
#7b01171000010001000100010001000100010001d6407d
#7b01070022307d
#7b010b00000008a5cd7d
#7b010c0600000000000061357d
#7b01110300ffacbc7d
#7b0114002f007d
#7b0115002e907d
#7b01160012ffff00004e217d
#7b01180012001000010001000100010001000100010001d74d7d
#7b012b0e01830000000faf7d
#7b010800000000e00b7d
#7b010800010000b1cb7d
#7b01080002000041cb7d
#7b010800030000100b7d
#7b0108000481d97d
#7b0108000a0000c0097d
#7b0108000b000091c97d
#7b0108000c000020087d
#7b0108000d000071c87d
#7b0108000e000081c87d
#7b0108000f0000d0087d
#7b010800100000e1ce7d
#7b010800110000b00e7d
#7b010800120000400e7d
#7b01080013000011ce7d
#7b010800140000a00f7d
#7b010800150000f1cf7d