class ModbusProtocol(ModbusBase):
def __init__(self,
updatecallback,
address = 0x9d,
name = "/dev/serial0",
rate = 9600,
Parity = None,
OnePointFiveStopBits = None,
config = None,
host = None,
port = None,
modbustcp = False): # True of Modbus TCP, else if TCP then assume serial over TCP (Modbus RTU over serial)
super(ModbusProtocol, self).__init__(updatecallback = updatecallback, address = address, name = name, rate = rate, config = config)
try:
if config == None:
self.ModbusTCP = modbustcp
self.Host = host
self.Port = port
self.TransactionID = 0
self.AlternateFileProtocol = False
if host != None and port != None and self.config == None:
# in this instance we do not use a config file, but config comes from command line
self.UseTCP = True
# ~3000 for 9600 bit time * 10 bits * 10 char * 2 packets + wait time(3000) (convert to ms * 1000)
self.ModBusPacketTimoutMS = (((((1/float(self.Rate)) * 10.0) * 10.0 * 2.0) *1000.0) + 3000.0) # .00208
self.ModBusPacketTimoutMS += self.AdditionalModbusTimeout * 1000.0
if self.ModbusTCP:
self.MIN_PACKET_RESPONSE_LENGTH -= 2
self.MBUS_RES_PAYLOAD_SIZE_MINUS_LENGTH -= 2
self.MBUS_FILE_READ_PAYLOAD_SIZE_MINUS_LENGTH -= 2
self.MBUS_CRC_SIZE = 0
self.MIN_PACKET_ERR_LENGTH -= 2
if self.UseTCP:
self.ModBusPacketTimoutMS = self.ModBusPacketTimoutMS + 2000
#Starting serial connection
if self.UseTCP:
self.Slave = SerialTCPDevice(config = self.config, host = host, port = port)
else:
self.Slave = SerialDevice(name = name, rate = rate, Parity = Parity, OnePointFiveStopBits = OnePointFiveStopBits, config = self.config)
self.Threads = self.MergeDicts(self.Threads, self.Slave.Threads)
except Exception as e1:
self.LogErrorLine("Error opening modbus device: " + str(e1))
self.FatalError("Error opening modbus device.")
try:
# CRCMOD library, used for CRC calculations
self.ModbusCrc = crcmod.predefined.mkCrcFun('modbus')
self.InitComplete = True
except Exception as e1:
self.FatalError("Unable to find crcmod package: " + str(e1))
#--------------------ModbusProtocol:GetExceptionString----------------------
def GetExceptionString(self, Code):
try:
LookUp = {
self.MBUS_EXCEP_FUNCTION : "Illegal Function",
self.MBUS_EXCEP_ADDRESS : "Illegal Address",
self.MBUS_EXCEP_DATA : "Illegal Data Value",
self.MBUS_EXCEP_SLAVE_FAIL : "Slave Device Failure",
self.MBUS_EXCEP_ACK : "Acknowledge",
self.MBUS_EXCEP_BUSY : "Slave Device Busy",
self.MBUS_EXCEP_NACK : "Negative Acknowledge",
self.MBUS_EXCEP_MEM_PE : "Memory Parity Error",
self.MBUS_EXCEP_GATEWAY : "Gateway Path Unavailable",
self.MBUS_EXCEP_GATEWAY_TG : "Gateway Target Device Failed to Respond"
}
if Code == self.MBUS_EXCEP_FUNCTION:
self.ExcepFunction += 1
elif Code == self.MBUS_EXCEP_ADDRESS:
self.ExcepAddress += 1
elif Code == self.MBUS_EXCEP_DATA:
self.ExcepData += 1
elif Code == self.MBUS_EXCEP_SLAVE_FAIL:
self.ExcepSlave += 1
elif Code == self.MBUS_EXCEP_ACK:
self.ExcepAck += 1
elif Code == self.MBUS_EXCEP_BUSY:
self.ExcepBusy += 1
elif Code == self.MBUS_EXCEP_NACK:
self.ExcepNack += 1
elif Code == self.MBUS_EXCEP_MEM_PE:
self.ExcepMemPe += 1
elif Code == self.MBUS_EXCEP_GATEWAY:
self.ExcepGateway += 1
elif Code == self.MBUS_EXCEP_GATEWAY_TG:
self.ExcepGateWayTg += 1
ReturnString = LookUp.get(Code, "Unknown")
ReturnString = ReturnString + (": %02x" % Code)
return ReturnString
except Exception as e1:
self.LogErrorLine("Error in GetExceptionString: " + str(e1))
return ""
# ---------- ModbusProtocol::CheckResponseAddress---------------------------
def CheckResponseAddress(self, Address):
if Address == self.Address:
return True
if self.ResponseAddress == None:
return False
if Address == self.ResponseAddress:
return True
return False
# ---------- ModbusProtocol::GetPacketFromSlave-----------------------------
# This function returns two values, the first is boolean. The seconds is
# a packet (list). If the return value is True and an empty packet, then
# keep looking because the data has not arrived yet, if return is False there
# is and error. If True and a non empty packet then it is valid data
def GetPacketFromSlave(self, min_response_override = None):
LocalErrorCount = 0
Packet = []
EmptyPacket = [] # empty packet
try:
if not len(self.Slave.Buffer):
return True, EmptyPacket
if self.ModbusTCP:
# byte 0: transaction identifier - copied by server - usually 0
# byte 1: transaction identifier - copied by server - usually 0
# byte 2: protocol identifier = 0
# byte 3: protocol identifier = 0
# byte 4: length field (upper byte) = 0 (since all messages are smaller than 256)
# byte 5: length field (lower byte) = number of bytes following
# byte 6: unit identifier (previously 'slave address')
# byte 7: MODBUS function code
# byte 8 on: data as needed
if len(self.Slave.Buffer) < (self.MIN_PACKET_ERR_LENGTH + self.MODBUS_TCP_HEADER_SIZE):
return True, EmptyPacket
# transaction ID must match
rxID = ((self.Slave.Buffer[0] <<8) | (self.Slave.Buffer[1] & 0xFF))
if self.CurrentTransactionID != rxID:
self.LogError("ModbusTCP transaction ID mismatch: %x %x" % (self.CurrentTransactionID, rxID))
self.DiscardByte(reason = "Transaction ID")
self.Flush()
return False, EmptyPacket
# protocol ID is zero
if self.Slave.Buffer[2] != 0 or self.Slave.Buffer[3] != 0:
self.LogError("ModbusTCP protocool ID non zero: %x %x" % (self.Slave.Buffer[2], self.Slave.Buffer[3]))
self.DiscardByte(reason = "protocol error")
self.Flush()
return False, EmptyPacket
# Modbus TCP payload length
ModbusTCPLength = ((self.Slave.Buffer[4] <<8) | (self.Slave.Buffer[5] & 0xFF))
if len(self.Slave.Buffer[6:]) != ModbusTCPLength:
# more data is needed
return True, EmptyPacket
# remove modbud TCP header
for i in range(0, self.MODBUS_TCP_HEADER_SIZE):
self.Slave.Buffer.pop(0)
if not self.CheckResponseAddress(self.Slave.Buffer[self.MBUS_OFF_ADDRESS]):
self.DiscardByte(reason = "Response Address")
self.Flush()
return False, EmptyPacket
if len(self.Slave.Buffer) < self.MIN_PACKET_ERR_LENGTH:
return True, EmptyPacket # No full packet ready
if self.Slave.Buffer[self.MBUS_OFF_COMMAND] & self.MBUS_ERROR_BIT:
for i in range(0, self.MIN_PACKET_ERR_LENGTH):
Packet.append(self.Slave.Buffer.pop(0)) # pop Address, Function, Excetion code, and CRC
if self.CheckCRC(Packet):
self.RxPacketCount += 1
self.ModbusException += 1
self.LogError("Modbus Exception: " + self.GetExceptionString(Packet[self.MBUS_OFF_EXCEPTION]) + " , Modbus Command: " + ("%02x" % Packet[self.MBUS_OFF_COMMAND]))
else:
self.CrcError += 1
return False, Packet
if min_response_override != None:
if len(self.Slave.Buffer) < min_response_override:
return True, EmptyPacket # No full packet ready
else:
if len(self.Slave.Buffer) < self.MIN_PACKET_RESPONSE_LENGTH:
return True, EmptyPacket # No full packet ready
if self.Slave.Buffer[self.MBUS_OFF_COMMAND] in [self.MBUS_CMD_READ_REGS]:
# it must be a read command response
length = self.Slave.Buffer[self.MBUS_OFF_RESPONSE_LEN] # our packet tells us the length of the payload
# if the full length of the packet has not arrived, return and try again
if (length + self.MBUS_RES_PAYLOAD_SIZE_MINUS_LENGTH) > len(self.Slave.Buffer):
return True, EmptyPacket
for i in range(0, length + self.MBUS_RES_PAYLOAD_SIZE_MINUS_LENGTH):
Packet.append(self.Slave.Buffer.pop(0)) # pop Address, Function, Length, message and CRC
if self.CheckCRC(Packet):
self.RxPacketCount += 1
return True, Packet
else:
self.CrcError += 1
return False, Packet
elif self.Slave.Buffer[self.MBUS_OFF_COMMAND] in [self.MBUS_CMD_WRITE_REGS]:
# it must be a write command response
if len(self.Slave.Buffer) < self.MIN_PACKET_MIN_WRITE_RESPONSE_LENGTH:
return True, EmptyPacket
for i in range(0, self.MIN_PACKET_MIN_WRITE_RESPONSE_LENGTH):
Packet.append(self.Slave.Buffer.pop(0)) # address, function, address hi, address low, quantity hi, quantity low, CRC high, crc low
if self.CheckCRC(Packet):
self.RxPacketCount += 1
return True, Packet
else:
self.CrcError += 1
return False, Packet
elif self.Slave.Buffer[self.MBUS_OFF_COMMAND] in [self.MBUS_CMD_READ_FILE]:
length = self.Slave.Buffer[self.MBUS_OFF_RESPONSE_LEN] # our packet tells us the length of the payload
if self.Slave.Buffer[self.MBUS_OFF_FILE_TYPE] != self.MBUS_FILE_TYPE_VALUE:
self.LogError("Invalid modbus file record type")
self.ComValidationError += 1
return False, EmptyPacket
# if the full length of the packet has not arrived, return and try again
if (length + self.MBUS_FILE_READ_PAYLOAD_SIZE_MINUS_LENGTH) > len(self.Slave.Buffer):
return True, EmptyPacket
# we will copy the entire buffer, this will be validated at a later time
for i in range(0, len(self.Slave.Buffer)):
Packet.append(self.Slave.Buffer.pop(0)) # pop Address, Function, Length, message and CRC
if len(self.Slave.Buffer):
self.LogHexList(self.Slave.Buffer, prefix = "Left Over")
if self.CheckCRC(Packet):
self.RxPacketCount += 1
return True, Packet
else:
self.CrcError += 1
return False, Packet
elif self.Slave.Buffer[self.MBUS_OFF_COMMAND] in [self.MBUS_CMD_WRITE_FILE]:
length = self.Slave.Buffer[self.MBUS_OFF_RESPONSE_LEN] # our packet tells us the length of the payload
if self.Slave.Buffer[self.MBUS_OFF_WRITE_FILE_TYPE] != self.MBUS_FILE_TYPE_VALUE:
self.LogError("Invalid modbus write file record type")
self.ComValidationError += 1
return False, EmptyPacket
# if the full length of the packet has not arrived, return and try again
if (length + self.MBUS_FILE_READ_PAYLOAD_SIZE_MINUS_LENGTH) > len(self.Slave.Buffer):
return True, EmptyPacket
# we will copy the entire buffer, this will be validated at a later time
for i in range(0, len(self.Slave.Buffer)):
Packet.append(self.Slave.Buffer.pop(0)) # pop Address, Function, Length, message and CRC
if len(self.Slave.Buffer):
self.LogHexList(self.Slave.Buffer, prefix = "Left Over")
if self.CheckCRC(Packet):
self.RxPacketCount += 1
return True, Packet
else:
self.CrcError += 1
return False, Packe
else:
# received a response to a command we do not support
self.DiscardByte(reason = "Invalid Modbus command")
self.Flush()
return False, EmptyPacket
except Exception as e1:
self.LogErrorLine("Error in GetPacketFromSlave: " + str(e1))
self.ComValidationError += 1
return False, EmptyPacket
# ---------- GeneratorDevice::DiscardByte-----------------------------------
def DiscardByte(self, reason = None):
discard = self.Slave.DiscardByte()
if reason == None:
reason = "Unknown"
self.LogError("Discarding byte slave: %02x : %s " % (discard, str(reason)))
#-------------ModbusProtocol::PWT-------------------------------------------
# called from derived calls to get to overridded function ProcessWriteTransaction
def _PWT(self, Register, Length, Data, min_response_override = None):
try:
with self.CommAccessLock:
MasterPacket = []
MasterPacket = self.CreateMasterPacket(Register, length = int(Length), command = self.MBUS_CMD_WRITE_REGS, data = Data)
if len(MasterPacket) == 0:
return False
#skipupdate=True to skip writing results to cached reg values
return self.ProcessOneTransaction(MasterPacket, skipupdate = True, min_response_override = min_response_override)
except Exception as e1:
self.LogErrorLine("Error in ProcessWriteTransaction: " + str(e1))
return False
#-------------ModbusProtocol::ProcessWriteTransaction-----------------------
def ProcessWriteTransaction(self, Register, Length, Data):
return self._PWT(Register, Length, Data)
#-------------ModbusProtocol::PT--------------------------------------------
# called from derived calls to get to overridded function ProcessTransaction
def _PT(self, Register, Length, skipupdate = False, ReturnString = False):
MasterPacket = []
try:
with self.CommAccessLock:
MasterPacket = self.CreateMasterPacket(Register, length = int(Length))
if len(MasterPacket) == 0:
return ""
return self.ProcessOneTransaction(MasterPacket, skipupdate = skipupdate, ReturnString = ReturnString) # don't log
except Exception as e1:
self.LogErrorLine("Error in ProcessTransaction: " + str(e1))
return ""
#-------------ModbusProtocol::ProcessTransaction----------------------------
def ProcessTransaction(self, Register, Length, skipupdate = False, ReturnString = False):
return self._PT(Register, Length, skipupdate, ReturnString)
#-------------ModbusProtocol::ProcessFileReadTransaction--------------------
def ProcessFileReadTransaction(self, Register, Length, skipupdate = False, file_num = 1, ReturnString = False):
MasterPacket = []
try:
with self.CommAccessLock:
MasterPacket = self.CreateMasterPacket(Register, length = int(Length), command = self.MBUS_CMD_READ_FILE, file_num = file_num)
if len(MasterPacket) == 0:
return ""
return self.ProcessOneTransaction(MasterPacket, skipupdate = skipupdate, ReturnString = ReturnString) # don't log
except Exception as e1:
self.LogErrorLine("Error in ProcessFileReadTransaction: " + str(e1))
return ""
#-------------ModbusProtocol::ProcessFileWriteTransaction-------------------
def ProcessFileWriteTransaction(self, Register, Length, Data, file_num = 1, min_response_override = None):
MasterPacket = []
try:
with self.CommAccessLock:
MasterPacket = self.CreateMasterPacket(Register, length = int(Length), command = self.MBUS_CMD_WRITE_FILE, file_num = file_num, data = Data)
if len(MasterPacket) == 0:
return ""
#skipupdate=True to skip writing results to cached reg values
return self.ProcessOneTransaction(MasterPacket, skipupdate = True, min_response_override = min_response_override)
except Exception as e1:
self.LogErrorLine("Error in ProcessFileWriteTransaction: " + str(e1))
return ""
#------------ModbusProtocol::ProcessOneTransaction--------------------------
def ProcessOneTransaction(self, MasterPacket, skipupdate = False, ReturnString = False, min_response_override = None):
try:
if self.ModbusTCP:
PacketOffset = self.MODBUS_TCP_HEADER_SIZE
else:
PacketOffset = 0
with self.CommAccessLock: # this lock should allow calls from multiple threads
if len(self.Slave.Buffer):
self.UnexpectedData += 1
self.LogError("Flushing, unexpected data. Likely timeout.")
self.Flush()
self.SendPacketAsMaster(MasterPacket)
SentTime = datetime.datetime.now()
while True:
# be kind to other processes, we know we are going to have to wait for the packet to arrive
# so let's sleep for a bit before we start polling
if self.SlowCPUOptimization:
time.sleep(0.03)
else:
time.sleep(0.01)
if self.IsStopping:
return ""
RetVal, SlavePacket = self.GetPacketFromSlave(min_response_override = min_response_override)
if RetVal == True and len(SlavePacket) != 0: # we receive a packet
self.TotalElapsedPacketeTime += (self.MillisecondsElapsed(SentTime) / 1000)
break
if RetVal == False:
self.LogError("Error Receiving slave packet for register %04x" % (self.GetRegisterFromPacket(MasterPacket, offset = PacketOffset) ))
# Errors returned here are logged in GetPacketFromSlave
time.sleep(1)
self.Flush()
return ""
msElapsed = self.MillisecondsElapsed(SentTime)
# This normally takes about 30 ms however in some instances it can take up to 950ms
# the theory is this is either a delay due to how python does threading, or
# delay caused by the generator controller.
# each char time is about 1 millisecond (at 9600 baud) so assuming a 10 byte packet
# transmitted and a 10 byte received with about 5 char times of silence
# in between should give us about 25ms
if msElapsed > self.ModBusPacketTimoutMS:
self.ComTimoutError += 1
self.LogError("Error: timeout receiving slave packet for register %04x Buffer: %d" % (self.GetRegisterFromPacket(MasterPacket, offset = PacketOffset), len(self.Slave.Buffer)) )
if len(self.Slave.Buffer):
self.LogHexList(self.Slave.Buffer, prefix = "Buffer")
self.Flush()
return ""
# update our cached register dict
ReturnRegValue = self.UpdateRegistersFromPacket(MasterPacket, SlavePacket, SkipUpdate = skipupdate, ReturnString = ReturnString)
if ReturnRegValue == "Error":
self.LogHexList(MasterPacket, prefix = "Master")
self.LogHexList(SlavePacket, prefix = "Slave")
self.ComValidationError += 1
self.Flush()
ReturnRegValue = ""
return ReturnRegValue
except Exception as e1:
self.LogErrorLine("Error in ProcessOneTransaction: " + str(e1))
return ""
# ---------- ModbusProtocol::MillisecondsElapsed----------------------------
def MillisecondsElapsed(self, ReferenceTime):
CurrentTime = datetime.datetime.now()
Delta = CurrentTime - ReferenceTime
return Delta.total_seconds() * 1000
#------------GetRegisterFromPacket -----------------------------------------
def GetRegisterFromPacket(self, Packet, offset = 0):
try:
Register = 0
if Packet[self.MBUS_OFF_COMMAND + offset] in [self.MBUS_CMD_READ_FILE,self.MBUS_CMD_WRITE_FILE] :
Register = Packet[self.MBUS_OFF_FILE_RECORD_HI + offset] << 8 | Packet[self.MBUS_OFF_FILE_RECORD_LOW + offset] & 0x00FF
else:
Register = Packet[self.MBUS_OFF_REGISTER_HI + offset] << 8 | Packet[self.MBUS_OFF_REGISTER_LOW + offset] & 0x00FF
return Register
except Exception as e1:
self.LogErrorLine("Error in GetRegisterFromPacket: " + str(e1))
return Register
# ---------- ModbusProtocol::CreateMasterPacket-----------------------------
# the length is the register length in words, as required by modbus
# build Packet
def CreateMasterPacket(self, register, length = 1, command = 0x03, data=[], file_num = 1):
Packet = []
try:
RegisterInt = int(register,16)
if RegisterInt < self.MIN_REGISTER or RegisterInt > self.MAX_REGISTER:
self.ComValidationError += 1
self.LogError("Validation Error: CreateMasterPacket maximum regiseter value exceeded: " + str(register))
return []
if file_num < self.MIN_FILE_NUMBER or file_num > self.MAX_FILE_NUMBER:
self.ComValidationError += 1
self.LogError("Validation Error: CreateMasterPacket maximum file number value exceeded: " + str(file_num))
return []
if command == self.MBUS_CMD_READ_REGS:
Packet.append(self.Address) # address
Packet.append(command) # command
Packet.append(RegisterInt >> 8) # reg high
Packet.append(RegisterInt & 0x00FF) # reg low
Packet.append(length >> 8) # length high
Packet.append(length & 0x00FF) # length low
CRCValue = self.GetCRC(Packet)
if CRCValue != None:
Packet.append(CRCValue & 0x00FF) # CRC low
Packet.append(CRCValue >> 8) # CRC high
elif command == self.MBUS_CMD_WRITE_REGS:
if len(data) == 0:
self.LogError("Validation Error: CreateMasterPacket invalid length (1) %x %x" % (len(data), length))
self.ComValidationError += 1
return []
if len(data)/2 != length:
self.LogError("Validation Error: CreateMasterPacket invalid length (2) %x %x" % (len(data), length))
self.ComValidationError += 1
return []
Packet.append(self.Address) # address
Packet.append(command) # command
Packet.append(RegisterInt >> 8) # reg higy
Packet.append(RegisterInt & 0x00FF) # reg low
Packet.append(length >> 8) # Num of Reg higy
Packet.append(length & 0x00FF) # Num of Reg low
Packet.append(len(data)) # byte count
for b in range(0, len(data)):
Packet.append(data[b]) # data
CRCValue = self.GetCRC(Packet)
if CRCValue != None:
Packet.append(CRCValue & 0x00FF) # CRC low
Packet.append(CRCValue >> 8) # CRC high
elif command == self.MBUS_CMD_READ_FILE:
# Note, we only support one sub request at at time
if RegisterInt < self.MIN_FILE_RECORD_NUM or RegisterInt > self.MAX_FILE_RECORD_NUM:
self.ComValidationError += 1
self.LogError("Validation Error: CreateMasterPacket maximum regiseter (record number) value exceeded: " + str(register))
return []
Packet.append(self.Address) # address
Packet.append(command) # command
Packet.append(self.MBUS_READ_FILE_REQUEST_PAYLOAD_LENGTH) # Byte count
Packet.append(self.MBUS_FILE_TYPE_VALUE) # always same value
Packet.append(file_num >> 8) # File Number hi
Packet.append(file_num & 0x00FF) # File Number low
Packet.append(RegisterInt >> 8) # register (file record number) high
Packet.append(RegisterInt & 0x00FF) # register (file record number) low
Packet.append(length >> 8) # Length to return hi
Packet.append(length & 0x00FF) # Length to return lo
CRCValue = self.GetCRC(Packet)
if CRCValue != None:
Packet.append(CRCValue & 0x00FF) # CRC low
Packet.append(CRCValue >> 8) # CRC high
elif command == self.MBUS_CMD_WRITE_FILE:
# Note, we only support one sub request at at time
if RegisterInt < self.MIN_FILE_RECORD_NUM or RegisterInt > self.MAX_FILE_RECORD_NUM:
self.ComValidationError += 1
self.LogError("Validation Error: CreateMasterPacket maximum regiseter (write record number) value exceeded: " + str(register))
return []
if len(data)/2 != length:
self.LogError("Validation Error: CreateMasterPacket invalid length (3) %x %x" % (len(data), length))
self.ComValidationError += 1
return []
Packet.append(self.Address) # address
Packet.append(command) # command
Packet.append(length * 2 + self.MBUS_FILE_WRITE_REQ_SIZE_MINUS_LENGTH) # packet payload size from here
Packet.append(self.MBUS_FILE_TYPE_VALUE) # always same value
Packet.append(file_num >> 8) # File Number hi
Packet.append(file_num & 0x00FF) # File Number low
Packet.append(RegisterInt >> 8) # register (file record number) high
Packet.append(RegisterInt & 0x00FF) # register (file record number) low
Packet.append(length >> 8) # Length to return hi
Packet.append(length & 0x00FF) # Length to return lo
for b in range(0, len(data)):
Packet.append(data[b]) # data
CRCValue = self.GetCRC(Packet)
if CRCValue != None:
Packet.append(CRCValue & 0x00FF) # CRC low
Packet.append(CRCValue >> 8) # CRC high
else:
self.LogError("Validation Error: Invalid command in CreateMasterPacket!")
self.ComValidationError += 1
return []
except Exception as e1:
self.LogErrorLine("Error in CreateMasterPacket: " + str(e1))
if len(Packet) > self.MAX_MODBUS_PACKET_SIZE:
self.LogError("Validation Error: CreateMasterPacket: Packet size exceeds max size")
self.ComValidationError += 1
return []
if self.ModbusTCP:
return self.ConvertToModbusModbusTCP(Packet)
return Packet
#-------------ModbusProtocol::GetTransactionID------------------------------
def GetTransactionID(self):
ID = self.TransactionID
self.CurrentTransactionID = ID
self.TransactionID += 1
if self.TransactionID > 0xffff:
self.TransactionID = 0
return ID
#-------------ModbusProtocol::ConvertToModbusModbusTCP----------------------
def ConvertToModbusModbusTCP(self, Packet):
# byte 0: transaction identifier - copied by server - usually 0
# byte 1: transaction identifier - copied by server - usually 0
# byte 2: protocol identifier = 0
# byte 3: protocol identifier = 0
# byte 4: length field (upper byte) = 0 (since all messages are smaller than 256)
# byte 5: length field (lower byte) = number of bytes following
# byte 6: unit identifier (previously 'slave address')
# byte 7: MODBUS function code
# byte 8 on: data as needed
try:
if not self.ModbusTCP:
return Packet
# remove last two bytes of CRC
Packet.pop()
Packet.pop()
length = len(Packet)
# byte 6 (slave address) is already provided in the Packet argument
Packet.insert(0,length & 0xff) # byte 5: length field (lower byte) = number of bytes following
Packet.insert(0,length & 0xff00) # byte 4: length field (upper byte) = 0 (since all messages are smaller than 256)
Packet.insert(0,0) # byte 3: protocol identifier = 0
Packet.insert(0,0) # byte 2: protocol identifier = 0
TransactionID = self.GetTransactionID()
Packet.insert(0, TransactionID & 0xff) # byte 1: transaction identifier (low)- copied by server - usually 0
Packet.insert(0, (TransactionID & 0xff00) >> 8) # byte 0: transaction identifier (high)- copied by server - usually 0
return Packet
except Exception as e1:
self.LogErrorLine("Error in CreateModbusTCPHeader: " + str(e1))
return []
#-------------ModbusProtocol::SendPacketAsMaster----------------------------
def SendPacketAsMaster(self, Packet):
try:
ByteArray = bytearray(Packet)
self.Slave.Write(ByteArray)
self.TxPacketCount += 1
except Exception as e1:
self.LogErrorLine("Error in SendPacketAsMaster: " + str(e1))
self.LogHexList(Packet, prefix = "Packet")
# ---------- ModbusProtocol::UpdateRegistersFromPacket----------------------
# Update our internal register list based on the request/response packet
def UpdateRegistersFromPacket(self, MasterPacket, SlavePacket, SkipUpdate = False, ReturnString = False):
return self._URFP(MasterPacket, SlavePacket, SkipUpdate, ReturnString)
# ---------- ModbusProtocol::URFP-------------------------------------------
# Called from UpdateRegistersFromPacket
def _URFP(self, MasterPacket, SlavePacket, SkipUpdate = False, ReturnString = False):
try:
if len(MasterPacket) < self.MIN_PACKET_RESPONSE_LENGTH or len(SlavePacket) < self.MIN_PACKET_RESPONSE_LENGTH:
self.LogError("Validation Error, length: Master" + str(len(MasterPacket)) + " Slave: " + str(len(SlavePacket)))
return "Error"
if self.ModbusTCP:
PacketOffset = self.MODBUS_TCP_HEADER_SIZE
else:
PacketOffset = 0
if MasterPacket[self.MBUS_OFF_ADDRESS + PacketOffset] != self.Address:
self.LogError("Validation Error: Invalid address in UpdateRegistersFromPacket (Master)")
return "Error"
if not self.CheckResponseAddress(SlavePacket[self.MBUS_OFF_ADDRESS]):
self.LogError("Validation Error: Invalid address in UpdateRegistersFromPacket (Slave)")
return "Error"
if not SlavePacket[self.MBUS_OFF_COMMAND] in [self.MBUS_CMD_READ_REGS, self.MBUS_CMD_WRITE_REGS, self.MBUS_CMD_READ_FILE, self.MBUS_CMD_WRITE_FILE]:
self.LogError("Validation Error: Unknown Function slave %02x %02x" % (SlavePacket[self.MBUS_OFF_ADDRESS],SlavePacket[self.MBUS_OFF_COMMAND]))
return "Error"
if not MasterPacket[self.MBUS_OFF_COMMAND + PacketOffset] in [self.MBUS_CMD_READ_REGS, self.MBUS_CMD_WRITE_REGS, self.MBUS_CMD_READ_FILE, self.MBUS_CMD_WRITE_FILE]:
self.LogError("Validation Error: Unknown Function master %02x %02x" % (MasterPacket[self.MBUS_OFF_ADDRESS],MasterPacket[self.MBUS_OFF_COMMAND]))
return "Error"
if MasterPacket[self.MBUS_OFF_COMMAND + PacketOffset] != SlavePacket[self.MBUS_OFF_COMMAND]:
self.LogError("Validation Error: Command Mismatch :" + str(MasterPacket[self.MBUS_OFF_COMMAND]) + ":" + str(SlavePacket[self.MBUS_OFF_COMMAND]))
return "Error"
# get register from master packet
Register = "%04x" % (self.GetRegisterFromPacket(MasterPacket, offset = PacketOffset))
if MasterPacket[self.MBUS_OFF_COMMAND + PacketOffset] in [self.MBUS_CMD_WRITE_REGS, self.MBUS_CMD_WRITE_FILE]:
# get register from slave packet
SlaveRegister = "%04x" % (self.GetRegisterFromPacket(SlavePacket))
if SlaveRegister != Register:
self.LogError("Validation Error: Master Slave Register Mismatch : " + Register + ":" + SlaveRegister)
return "Error"
RegisterValue = ""
RegisterStringValue = ""
if MasterPacket[self.MBUS_OFF_COMMAND + PacketOffset] == self.MBUS_CMD_READ_REGS:
# get value from slave packet
length = SlavePacket[self.MBUS_OFF_RESPONSE_LEN]
if (length + self.MBUS_RES_PAYLOAD_SIZE_MINUS_LENGTH) > len(SlavePacket):
self.LogError("Validation Error: Slave Length : " + length + ":" + len(SlavePacket))
return "Error"
for i in range(3, length+3):
RegisterValue += "%02x" % SlavePacket[i]
if ReturnString:
if SlavePacket[i]:
RegisterStringValue += chr(SlavePacket[i])
# update register list
if not SkipUpdate:
if not self.UpdateRegisterList == None:
if not ReturnString:
if not self.UpdateRegisterList(Register, RegisterValue):
self.ComSyncError += 1
return "Error"
else:
if not self.UpdateRegisterList(Register, RegisterStringValue, IsString = True):
self.ComSyncError += 1
return "Error"
if MasterPacket[self.MBUS_OFF_COMMAND + PacketOffset] == self.MBUS_CMD_READ_FILE:
payloadLen = SlavePacket[self.MBUS_OFF_FILE_PAYLOAD_LEN]
if not self.AlternateFileProtocol:
# TODO This is emperical
payloadLen -= 1
for i in range (self.MBUS_OFF_FILE_PAYLOAD, (self.MBUS_OFF_FILE_PAYLOAD + payloadLen)):
RegisterValue += "%02x" % SlavePacket[i]
if ReturnString:
if SlavePacket[i]:
RegisterStringValue += chr(SlavePacket[i])
if not SkipUpdate:
if not ReturnString:
if not self.UpdateRegisterList(Register, RegisterValue, IsFile = True):
self.ComSyncError += 1
return "Error"
else:
if not self.UpdateRegisterList(Register, RegisterStringValue, IsString = True, IsFile = True):
self.ComSyncError += 1
return "Error"
if ReturnString:
return str(RegisterStringValue)
return str(RegisterValue)
except Exception as e1:
self.LogErrorLine("Error in UpdateRegistersFromPacket: " + str(e1))
return "Error"
#------------ModbusProtocol::CheckCrc--------------------------------------
def CheckCRC(self, Packet):
try:
if self.ModbusTCP:
return True
if len(Packet) == 0:
return False
ByteArray = bytearray(Packet[:len(Packet)-2])
if sys.version_info[0] < 3:
results = self.ModbusCrc(str(ByteArray))
else: # PYTHON3
results = self.ModbusCrc(ByteArray)
CRCValue = ( ( Packet[-1] & 0xFF ) << 8 ) | ( Packet[ -2] & 0xFF )
if results != CRCValue:
self.LogError("Data Error: CRC check failed: %04x %04x" % (results, CRCValue))
return False
return True
except Exception as e1:
self.LogErrorLine("Error in CheckCRC: " + str(e1))
self.LogHexList(Packet, prefix = "Packet")
return False
#------------ModbusProtocol::GetCRC----------------------------------------
def GetCRC(self, Packet):
try:
if len(Packet) == 0:
return None
ByteArray = bytearray(Packet)
if sys.version_info[0] < 3:
results = self.ModbusCrc(str(ByteArray))
else: # PYTHON3
results = self.ModbusCrc(ByteArray)
return results
except Exception as e1:
self.LogErrorLine("Error in GetCRC: " + str(e1))
self.LogHexList(Packet, prefix = "Packet")
return None
# ---------- ModbusProtocol::GetCommStats-----------------------------------
def GetCommStats(self):
SerialStats = []
try:
SerialStats.append({"Packet Count" : "M: %d, S: %d" % (self.TxPacketCount, self.RxPacketCount)})
if self.CrcError == 0 or self.TxPacketCount == 0:
PercentErrors = 0.0
else:
PercentErrors = float(self.CrcError) / float(self.TxPacketCount)
if self.ComTimoutError == 0 or self.TxPacketCount == 0:
PercentTimeoutErrors = 0.0
else:
PercentTimeoutErrors = float(self.ComTimoutError) / float(self.TxPacketCount)
SerialStats.append({"CRC Errors" : "%d " % self.CrcError})
SerialStats.append({"CRC Percent Errors" : ("%.2f" % (PercentErrors * 100)) + "%"})
SerialStats.append({"Timeout Errors" : "%d" % self.ComTimoutError})
SerialStats.append({"Timeout Percent Errors" : ("%.2f" % (PercentTimeoutErrors * 100)) + "%"})
SerialStats.append({"Modbus Exceptions" : self.ModbusException})
SerialStats.append({"Validation Errors" : self.ComValidationError})
SerialStats.append({"Sync Errors" : self.ComSyncError})
SerialStats.append({"Invalid Data" : self.UnexpectedData})
# add serial stats
SerialStats.append({"Discarded Bytes" : "%d" % self.Slave.DiscardedBytes})
SerialStats.append({"Comm Restarts" : "%d" % self.Slave.Restarts})
CurrentTime = datetime.datetime.now()
#
Delta = CurrentTime - self.ModbusStartTime # yields a timedelta object
PacketsPerSecond = float((self.TxPacketCount + self.RxPacketCount)) / float(Delta.total_seconds())
SerialStats.append({"Packets Per Second" : "%.2f" % (PacketsPerSecond)})
if self.RxPacketCount:
AvgTransactionTime = float(self.TotalElapsedPacketeTime / self.RxPacketCount)
SerialStats.append({"Average Transaction Time" : "%.4f sec" % (AvgTransactionTime)})
except Exception as e1:
self.LogErrorLine("Error in GetCommStats: " + str(e1))
return SerialStats
# ---------- ModbusProtocol::ResetCommStats---------------------------------
def ResetCommStats(self):
try:
self.RxPacketCount = 0
self.TxPacketCount = 0
self.TotalElapsedPacketeTime = 0
self.ModbusStartTime = datetime.datetime.now() # used for com metrics
self.Slave.ResetSerialStats()
except Exception as e1:
self.LogErrorLine("Error in ResetCommStats: " + str(e1))
#------------ModbusProtocol::Flush------------------------------------------
def Flush(self):
self.Slave.Flush()
#------------ModbusProtocol::Close------------------------------------------
def Close(self):
self.IsStopping = True
self.Slave.Close()
class ModbusProtocol(ModbusBase):
def __init__(self,
updatecallback,
address = 0x9d,
name = "/dev/serial0",
rate=9600,
Parity = None,
OnePointFiveStopBits = None,
config = None):
super(ModbusProtocol, self).__init__(updatecallback = updatecallback, address = address, name = name, rate = rate, config = config)
try:
# ~3000 for 9600 bit time * 10 bits * 10 char * 2 packets + wait time(3000) (convert to ms * 1000)
self.ModBusPacketTimoutMS = (((((1/float(rate)) * 10.0) * 10.0 * 2.0) *1000.0) + 3000.0) # .00208
self.ModBusPacketTimoutMS += self.AdditionalModbusTimeout * 1000.0
if self.UseTCP:
self.ModBusPacketTimoutMS = self.ModBusPacketTimoutMS
#Starting serial connection
if self.UseTCP:
self.Slave = SerialTCPDevice(config = self.config)
else:
self.Slave = SerialDevice(name = name, rate = rate, Parity = Parity, OnePointFiveStopBits = OnePointFiveStopBits, config = self.config)
self.Threads = self.MergeDicts(self.Threads, self.Slave.Threads)
except Exception as e1:
self.LogErrorLine("Error opening serial device: " + str(e1))
self.FatalError("Error opening serial device.")
try:
# CRCMOD library, used for CRC calculations
self.ModbusCrc = crcmod.predefined.mkCrcFun('modbus')
self.InitComplete = True
except Exception as e1:
self.FatalError("Unable to find crcmod package: " + str(e1))
#--------------------ModbusProtocol:GetExceptionString----------------------
def GetExceptionString(self, Code):
try:
LookUp = {
MBUS_EXCEP_FUNCTION : "Illegal Function",
MBUS_EXCEP_ADDRESS : "Illegal Address",
MBUS_EXCEP_DATA : "Illegal Data Value",
MBUS_EXCEP_SLAVE_FAIL : "Slave Device Failure",
MBUS_EXCEP_ACK : "Acknowledge",
MBUS_EXCEP_BUSY : "Slave Device Busy",
MBUS_EXCEP_NACK : "Negative Acknowledge",
MBUS_EXCEP_MEM_PE : "Memory Parity Error",
MBUS_EXCEP_GATEWAY : "Gateway Path Unavailable",
MBUS_EXCEP_GATEWAY_TG : "Gateway Target Device Failed to Respond"
}
ReturnString = LookUp.get(Code, "Unknown")
ReturnString = ReturnString + (": %02x" % Code)
return ReturnString
except Exception as e1:
self.LogErrorLine("Error in GetExceptionString: " + str(e1))
return ""
# ---------- ModbusProtocol::CheckResponseAddress---------------------------
def CheckResponseAddress(self, Address):
if Address == self.Address:
return True
if self.ResponseAddress == None:
return False
if Address == self.ResponseAddress:
return True
return False
# ---------- ModbusProtocol::GetPacketFromSlave-----------------------------
# This function returns two values, the first is boolean. The seconds is
# a packet (list). If the return value is True and an empty packet, then
# keep looking because the data has not arrived yet, if return is False there
# is and error. If True and a non empty packet then it is valid data
def GetPacketFromSlave(self):
LocalErrorCount = 0
Packet = []
EmptyPacket = [] # empty packet
try:
if not len(self.Slave.Buffer):
return True, EmptyPacket
if not self.CheckResponseAddress(self.Slave.Buffer[MBUS_OFF_ADDRESS]):
self.DiscardByte()
self.Flush()
return False, EmptyPacket
if len(self.Slave.Buffer) < MIN_PACKET_ERR_LENGTH:
return True, EmptyPacket # No full packet ready
if self.Slave.Buffer[MBUS_OFF_COMMAND] & MBUS_ERROR_BIT:
for i in range(0, MIN_PACKET_ERR_LENGTH):
Packet.append(self.Slave.Buffer.pop(0)) # pop Address, Function, Excetion code, and CRC
if self.CheckCRC(Packet):
self.RxPacketCount += 1
self.SlaveException += 1
self.LogError("Modbus Exception: " + self.GetExceptionString(Packet[MBUS_OFF_EXCEPTION]) + " , Modbus Command: " + ("%02x" % Packet[MBUS_OFF_COMMAND]))
else:
self.CrcError += 1
return False, Packet
if len(self.Slave.Buffer) < MIN_PACKET_RESPONSE_LENGTH:
return True, EmptyPacket # No full packet ready
if self.Slave.Buffer[MBUS_OFF_COMMAND] in [MBUS_CMD_READ_REGS]:
# it must be a read command response
length = self.Slave.Buffer[MBUS_OFF_RESPONSE_LEN] # our packet tells us the length of the payload
# if the full length of the packet has not arrived, return and try again
if (length + MBUS_RES_PAYLOAD_SIZE_MINUS_LENGTH) > len(self.Slave.Buffer):
return True, EmptyPacket
for i in range(0, length + MBUS_RES_PAYLOAD_SIZE_MINUS_LENGTH):
Packet.append(self.Slave.Buffer.pop(0)) # pop Address, Function, Length, message and CRC
if self.CheckCRC(Packet):
self.RxPacketCount += 1
return True, Packet
else:
self.CrcError += 1
return False, Packet
elif self.Slave.Buffer[MBUS_OFF_COMMAND] in [MBUS_CMD_WRITE_REGS]:
# it must be a write command response
if len(self.Slave.Buffer) < MIN_PACKET_MIN_WRITE_RESPONSE_LENGTH:
return True, EmptyPacket
for i in range(0, MIN_PACKET_MIN_WRITE_RESPONSE_LENGTH):
Packet.append(self.Slave.Buffer.pop(0)) # address, function, address hi, address low, quantity hi, quantity low, CRC high, crc low
if self.CheckCRC(Packet):
self.RxPacketCount += 1
return True, Packet
else:
self.CrcError += 1
return False, Packet
elif self.Slave.Buffer[MBUS_OFF_COMMAND] in [MBUS_CMD_READ_FILE]:
length = self.Slave.Buffer[MBUS_OFF_RESPONSE_LEN] # our packet tells us the length of the payload
if self.Slave.Buffer[MBUS_OFF_FILE_TYPE] != MBUS_FILE_TYPE_VALUE:
self.LogError("Invalid modbus file record type")
self.ComValidationError += 1
return False, EmptyPacket
# if the full length of the packet has not arrived, return and try again
if (length + MBUS_FILE_READ_PAYLOAD_SIZE_MINUS_LENGTH) > len(self.Slave.Buffer):
return True, EmptyPacket
for i in range(0, length + MBUS_FILE_READ_PAYLOAD_SIZE_MINUS_LENGTH):
Packet.append(self.Slave.Buffer.pop(0)) # pop Address, Function, Length, message and CRC
if self.CheckCRC(Packet):
self.RxPacketCount += 1
return True, Packet
else:
self.CrcError += 1
return False, Packet
else:
# received a response to a command we do not support
self.DiscardByte()
self.Flush()
return False, EmptyPacket
except Exception as e1:
self.LogErrorLine("Error in GetPacketFromSlave: " + str(e1))
self.SlaveException += 1
return False, EmptyPacket
# ---------- GeneratorDevice::DiscardByte-----------------------------------
def DiscardByte(self):
discard = self.Slave.DiscardByte()
self.LogError("Discarding byte slave: %02x" % (discard))
#-------------ModbusProtocol::ProcessMasterSlaveWriteTransaction------------
def ProcessMasterSlaveWriteTransaction(self, Register, Length, Data):
try:
MasterPacket = []
MasterPacket = self.CreateMasterPacket(Register, length = int(Length), command = MBUS_CMD_WRITE_REGS, data = Data)
if len(MasterPacket) == 0:
return False
return self.ProcessOneTransaction(MasterPacket, skipupdate = True) # True to skip writing results to cached reg values
except Exception as e1:
self.LogErrorLine("Error in ProcessMasterSlaveWriteTransaction: " + str(e1))
return False
#-------------ModbusProtocol::ProcessMasterSlaveTransaction-----------------
def ProcessMasterSlaveTransaction(self, Register, Length, skipupdate = False, ReturnString = False):
MasterPacket = []
try:
MasterPacket = self.CreateMasterPacket(Register, length = int(Length))
if len(MasterPacket) == 0:
return ""
return self.ProcessOneTransaction(MasterPacket, skipupdate = skipupdate, ReturnString = ReturnString) # don't log
except Exception as e1:
self.LogErrorLine("Error in ProcessMasterSlaveTransaction: " + str(e1))
return ""
#-------------ModbusProtocol::ProcessMasterSlaveFileReadTransaction---------
def ProcessMasterSlaveFileReadTransaction(self, Register, Length, skipupdate = False, file_num = 1, ReturnString = False):
MasterPacket = []
try:
MasterPacket = self.CreateMasterPacket(Register, length = int(Length), command = MBUS_CMD_READ_FILE, file_num = file_num)
if len(MasterPacket) == 0:
return ""
return self.ProcessOneTransaction(MasterPacket, skipupdate = skipupdate, ReturnString = ReturnString) # don't log
except Exception as e1:
self.LogErrorLine("Error in ProcessMasterSlaveFileReadTransaction: " + str(e1))
return ""
#------------ModbusProtocol::ProcessOneTransaction--------------------------
def ProcessOneTransaction(self, MasterPacket, skipupdate = False, ReturnString = False):
try:
with self.CommAccessLock: # this lock should allow calls from multiple threads
if len(self.Slave.Buffer):
self.UnexpectedData += 1
self.LogError("Flushing, unexpected data. Likely timeout.")
self.Flush()
self.SendPacketAsMaster(MasterPacket)
SentTime = datetime.datetime.now()
while True:
# be kind to other processes, we know we are going to have to wait for the packet to arrive
# so let's sleep for a bit before we start polling
if self.SlowCPUOptimization:
time.sleep(0.03)
else:
time.sleep(0.01)
if self.IsStopping:
return ""
RetVal, SlavePacket = self.GetPacketFromSlave()
if RetVal == True and len(SlavePacket) != 0: # we receive a packet
self.TotalElapsedPacketeTime += (self.MillisecondsElapsed(SentTime) / 1000)
break
if RetVal == False:
self.LogError("Error Receiving slave packet for register %04x" % (self.GetRegisterFromPacket(MasterPacket) ))
# Errors returned here are logged in GetPacketFromSlave
self.Flush()
return ""
msElapsed = self.MillisecondsElapsed(SentTime)
# This normally takes about 30 ms however in some instances it can take up to 950ms
# the theory is this is either a delay due to how python does threading, or
# delay caused by the generator controller.
# each char time is about 1 millisecond (at 9600 baud) so assuming a 10 byte packet
# transmitted and a 10 byte received with about 5 char times of silence
# in between should give us about 25ms
if msElapsed > self.ModBusPacketTimoutMS:
self.ComTimoutError += 1
self.LogError("Error: timeout receiving slave packet for register %04x Buffer:%d" % (self.GetRegisterFromPacket(MasterPacket), len(self.Slave.Buffer)) )
if len(self.Slave.Buffer):
self.LogError("Buffer: " + str(self.Slave.Buffer))
self.Flush()
return ""
# update our cached register dict
ReturnRegValue = self.UpdateRegistersFromPacket(MasterPacket, SlavePacket, SkipUpdate = skipupdate, ReturnString = ReturnString)
if ReturnRegValue == "Error":
self.LogError("Master: " + str(MasterPacket))
self.LogError("Slave: " + str(SlavePacket))
self.ComValidationError += 1
self.Flush()
ReturnRegValue = ""
return ReturnRegValue
except Exception as e1:
self.LogErrorLine("Error in ProcessOneTransaction: " + str(e1))
return ""
# ---------- ModbusProtocol::MillisecondsElapsed----------------------------
def MillisecondsElapsed(self, ReferenceTime):
CurrentTime = datetime.datetime.now()
Delta = CurrentTime - ReferenceTime
return Delta.total_seconds() * 1000
#------------GetRegisterFromPacket -----------------------------------------
def GetRegisterFromPacket(self, Packet):
try:
Register = 0
if Packet[MBUS_OFF_COMMAND] == MBUS_CMD_READ_FILE:
Register = Packet[MBUS_OFF_FILE_RECORD_HI] << 8 | Packet[MBUS_OFF_FILE_RECORD_LOW] & 0x00FF
else:
Register = Packet[MBUS_OFF_REGISTER_HI] << 8 | Packet[MBUS_OFF_REGISTER_LOW] & 0x00FF
return Register
except Exception as e1:
self.LogErrorLine("Error in GetRegisterFromPacket: " + str(e1))
return Register
# ---------- ModbusProtocol::CreateMasterPacket-----------------------------
# the length is the register length in words, as required by modbus
# build Packet
def CreateMasterPacket(self, register, length = 1, command = MBUS_CMD_READ_REGS, data=[], file_num = 1):
Packet = []
try:
RegisterInt = int(register,16)
if RegisterInt < MIN_REGISTER or RegisterInt > MAX_REGISTER:
self.ComValidationError += 1
self.LogError("Validation Error: CreateMasterPacket maximum regiseter value exceeded: " + str(register))
return []
if file_num < MIN_FILE_NUMBER or file_num > MAX_FILE_NUMBER:
self.ComValidationError += 1
self.LogError("Validation Error: CreateMasterPacket maximum file number value exceeded: " + str(file_num))
return []
if command == MBUS_CMD_READ_REGS:
Packet.append(self.Address) # address
Packet.append(command) # command
Packet.append(RegisterInt >> 8) # reg higy
Packet.append(RegisterInt & 0x00FF) # reg low
Packet.append(length >> 8) # length high
Packet.append(length & 0x00FF) # length low
CRCValue = self.GetCRC(Packet)
Packet.append(CRCValue & 0x00FF) # CRC low
Packet.append(CRCValue >> 8) # CRC high
elif command == MBUS_CMD_WRITE_REGS:
if len(data) == 0:
self.LogError("Validation Error: CreateMasterPacket invalid length (1) %x %x" % (len(data), length))
self.ComValidationError += 1
return []
if len(data)/2 != length:
self.LogError("Validation Error: CreateMasterPacket invalid length (2) %x %x" % (len(data), length))
self.ComValidationError += 1
return []
Packet.append(self.Address) # address
Packet.append(command) # command
Packet.append(RegisterInt >> 8) # reg higy
Packet.append(RegisterInt & 0x00FF) # reg low
Packet.append(length >> 8) # Num of Reg higy
Packet.append(length & 0x00FF) # Num of Reg low
Packet.append(len(data)) # byte count
for b in range(0, len(data)):
Packet.append(data[b]) # data
CRCValue = self.GetCRC(Packet)
Packet.append(CRCValue & 0x00FF) # CRC low
Packet.append(CRCValue >> 8) # CRC high
elif command == MBUS_CMD_READ_FILE:
# Note, we only support one sub request at at time
if RegisterInt < MIN_FILE_RECORD_NUM or RegisterInt > MAX_FILE_RECORD_NUM:
self.ComValidationError += 1
self.LogError("Validation Error: CreateMasterPacket maximum regiseter (record number) value exceeded: " + str(register))
return []
Packet.append(self.Address) # address
Packet.append(command) # command
Packet.append(MBUS_READ_FILE_REQUEST_PAYLOAD_LENGTH) # Byte count
Packet.append(MBUS_FILE_TYPE_VALUE) # always same value
Packet.append(file_num >> 8) # File Number hi
Packet.append(file_num & 0x00FF) # File Number low
Packet.append(RegisterInt >> 8) # register (file record number) high
Packet.append(RegisterInt & 0x00FF) # register (file record number) low
Packet.append(length >> 8) # Length to return hi
Packet.append(length & 0x00FF) # Length to return lo
CRCValue = self.GetCRC(Packet)
Packet.append(CRCValue & 0x00FF) # CRC low
Packet.append(CRCValue >> 8) # CRC high
else:
self.LogError("Validation Error: Invalid command in CreateMasterPacket!")
self.ComValidationError += 1
return []
except Exception as e1:
self.LogErrorLine("Error in CreateMasterPacket: " + str(e1))
if len(Packet) > MAX_MODBUS_PACKET_SIZE:
self.LogError("Validation Error: CreateMasterPacket: Packet size exceeds max size")
self.ComValidationError += 1
return []
return Packet
#-------------ModbusProtocol::SendPacketAsMaster----------------------------
def SendPacketAsMaster(self, Packet):
try:
ByteArray = bytearray(Packet)
self.Slave.Write(ByteArray)
self.TxPacketCount += 1
except Exception as e1:
self.LogErrorLine("Error in SendPacketAsMaster: " + str(e1))
self.LogError("Packet: " + str(Packet))
# ---------- ModbusProtocol::UpdateRegistersFromPacket----------------------
# Update our internal register list based on the request/response packet
def UpdateRegistersFromPacket(self, MasterPacket, SlavePacket, SkipUpdate = False, ReturnString = False):
try:
if len(MasterPacket) < MIN_PACKET_RESPONSE_LENGTH or len(SlavePacket) < MIN_PACKET_RESPONSE_LENGTH:
self.LogError("Validation Error, length: Master" + str(len(MasterPacket)) + " Slave: " + str(len(SlavePacket)))
return "Error"
if MasterPacket[MBUS_OFF_ADDRESS] != self.Address:
self.LogError("Validation Error: Invalid address in UpdateRegistersFromPacket (Master)")
return "Error"
if not self.CheckResponseAddress(SlavePacket[MBUS_OFF_ADDRESS]):
self.LogError("Validation Error: Invalid address in UpdateRegistersFromPacket (Slave)")
return "Error"
if not SlavePacket[MBUS_OFF_COMMAND] in [MBUS_CMD_READ_REGS, MBUS_CMD_WRITE_REGS, MBUS_CMD_READ_FILE]:
self.LogError("Validation Error: Unknown Function slave %02x %02x" % (SlavePacket[MBUS_OFF_ADDRESS],SlavePacket[MBUS_OFF_COMMAND]))
return "Error"
if not MasterPacket[MBUS_OFF_COMMAND] in [MBUS_CMD_READ_REGS, MBUS_CMD_WRITE_REGS, MBUS_CMD_READ_FILE]:
self.LogError("Validation Error: Unknown Function master %02x %02x" % (MasterPacket[MBUS_OFF_ADDRESS],MasterPacket[MBUS_OFF_COMMAND]))
return "Error"
if MasterPacket[MBUS_OFF_COMMAND] != SlavePacket[MBUS_OFF_COMMAND]:
self.LogError("Validation Error: Command Mismatch :" + str(MasterPacket[MBUS_OFF_COMMAND]) + ":" + str(SlavePacket[MBUS_OFF_COMMAND]))
return "Error"
# get register from master packet
Register = "%04x" % (self.GetRegisterFromPacket(MasterPacket))
if MasterPacket[MBUS_OFF_COMMAND] == MBUS_CMD_WRITE_REGS:
# get register from slave packet
SlaveRegister = "%04x" % (self.GetRegisterFromPacket(SlavePacket))
if SlaveRegister != Register:
self.LogError("Validation Error: Master Slave Register Mismatch : " + Register + ":" + SlaveRegister)
return "Error"
RegisterValue = ""
RegisterStringValue = ""
if MasterPacket[MBUS_OFF_COMMAND] == MBUS_CMD_READ_REGS:
# get value from slave packet
length = SlavePacket[MBUS_OFF_RESPONSE_LEN]
if (length + MBUS_RES_PAYLOAD_SIZE_MINUS_LENGTH) > len(SlavePacket):
self.LogError("Validation Error: Slave Lenght : " + length + ":" + len(SlavePacket))
return "Error"
for i in range(3, length+3):
RegisterValue += "%02x" % SlavePacket[i]
if ReturnString:
if SlavePacket[i]:
RegisterStringValue += chr(SlavePacket[i])
# update register list
if not SkipUpdate:
if not self.UpdateRegisterList == None:
if not ReturnString:
self.UpdateRegisterList(Register, RegisterValue)
else:
self.UpdateRegisterList(Register, RegisterStringValue, IsString = True)
if MasterPacket[MBUS_OFF_COMMAND] == MBUS_CMD_READ_FILE:
payloadLen = SlavePacket[MBUS_OFF_FILE_PAYLOAD_LEN]
payloadLen -= 1
for i in range (MBUS_OFF_FILE_PAYLOAD, MBUS_OFF_FILE_PAYLOAD + payloadLen):
RegisterValue += "%02x" % SlavePacket[i]
if ReturnString:
if SlavePacket[i]:
RegisterStringValue += chr(SlavePacket[i])
if not SkipUpdate:
if not ReturnString:
self.UpdateRegisterList(Register, RegisterValue, IsFile = True)
else:
self.UpdateRegisterList(Register, RegisterStringValue, IsString = True, IsFile = True)
pass
if ReturnString:
return str(RegisterStringValue)
return str(RegisterValue)
except Exception as e1:
self.LogErrorLine("Error in UpdateRegistersFromPacket: " + str(e1))
return "Error"
#------------ModbusProtocol::CheckCrc--------------------------------------
def CheckCRC(self, Packet):
try:
if len(Packet) == 0:
return False
ByteArray = bytearray(Packet[:len(Packet)-2])
if sys.version_info[0] < 3:
results = self.ModbusCrc(str(ByteArray))
else: # PYTHON3
results = self.ModbusCrc(ByteArray)
CRCValue = ( ( Packet[-1] & 0xFF ) << 8 ) | ( Packet[ -2] & 0xFF )
if results != CRCValue:
self.LogError("Data Error: CRC check failed: %04x %04x" % (results, CRCValue))
return False
return True
except Exception as e1:
self.LogErrorLine("Error in CheckCRC: " + str(e1))
self.LogError("Packet: " + str(Packet))
return False
#------------ModbusProtocol::GetCRC----------------------------------------
def GetCRC(self, Packet):
try:
if len(Packet) == 0:
return False
ByteArray = bytearray(Packet)
if sys.version_info[0] < 3:
results = self.ModbusCrc(str(ByteArray))
else: # PYTHON3
results = self.ModbusCrc(ByteArray)
return results
except Exception as e1:
self.LogErrorLine("Error in GetCRC: " + str(e1))
self.LogError("Packet: " + str(Packet))
return 0
# ---------- ModbusProtocol::GetCommStats-----------------------------------
def GetCommStats(self):
SerialStats = []
try:
SerialStats.append({"Packet Count" : "M: %d, S: %d" % (self.TxPacketCount, self.RxPacketCount)})
if self.CrcError == 0 or self.TxPacketCount == 0:
PercentErrors = 0.0
else:
PercentErrors = float(self.CrcError) / float(self.TxPacketCount)
if self.ComTimoutError == 0 or self.TxPacketCount == 0:
PercentTimeoutErrors = 0.0
else:
PercentTimeoutErrors = float(self.ComTimoutError) / float(self.TxPacketCount)
SerialStats.append({"CRC Errors" : "%d " % self.CrcError})
SerialStats.append({"CRC Percent Errors" : ("%.2f" % (PercentErrors * 100)) + "%"})
SerialStats.append({"Packet Timeouts" : "%d" % self.ComTimoutError})
SerialStats.append({"Packet Timeouts Percent Errors" : ("%.2f" % (PercentTimeoutErrors * 100)) + "%"})
SerialStats.append({"Modbus Exceptions" : self.SlaveException})
SerialStats.append({"Validation Errors" : self.ComValidationError})
SerialStats.append({"Invalid Data" : self.UnexpectedData})
# add serial stats
SerialStats.append({"Discarded Bytes" : "%d" % self.Slave.DiscardedBytes})
SerialStats.append({"Comm Restarts" : "%d" % self.Slave.Restarts})
CurrentTime = datetime.datetime.now()
#
Delta = CurrentTime - self.ModbusStartTime # yields a timedelta object
PacketsPerSecond = float((self.TxPacketCount + self.RxPacketCount)) / float(Delta.total_seconds())
SerialStats.append({"Packets Per Second" : "%.2f" % (PacketsPerSecond)})
if self.RxPacketCount:
AvgTransactionTime = float(self.TotalElapsedPacketeTime / self.RxPacketCount)
SerialStats.append({"Average Transaction Time" : "%.4f sec" % (AvgTransactionTime)})
except Exception as e1:
self.LogErrorLine("Error in GetCommStats: " + str(e1))
return SerialStats
# ---------- ModbusProtocol::ResetCommStats---------------------------------
def ResetCommStats(self):
try:
self.RxPacketCount = 0
self.TxPacketCount = 0
self.TotalElapsedPacketeTime = 0
self.ModbusStartTime = datetime.datetime.now() # used for com metrics
self.Slave.ResetSerialStats()
except Exception as e1:
self.LogErrorLine("Error in ResetCommStats: " + str(e1))
#------------ModbusProtocol::Flush------------------------------------------
def Flush(self):
self.Slave.Flush()
#------------ModbusProtocol::Close------------------------------------------
def Close(self):
self.IsStopping = True
self.Slave.Close()