def write_single_register(self, starting_address, value):
"""
Write single Register to Master device (Function code 6)
starting_address: Register to be written
value: Register Value to be written
"""
self.__transactionIdentifier += 1
if (self.__ser is not None):
if (self.__ser.closed):
raise Exception.SerialPortNotOpenedException(
"serial port not opened")
function_code = 6
length = 6
transaction_identifier_lsb = self.__transactionIdentifier & 0xFF
transaction_identifier_msb = (
(self.__transactionIdentifier & 0xFF00) >> 8)
length_lsb = length & 0xFF
length_msb = (length & 0xFF00) >> 8
starting_address_lsb = starting_address & 0xFF
starting_address_msb = (starting_address & 0xFF00) >> 8
valueLSB = value & 0xFF
valueMSB = (value & 0xFF00) >> 8
if (self.__ser is not None):
data = bytearray([
self.__unitIdentifier, function_code, starting_address_msb,
starting_address_lsb, valueMSB, valueLSB, 0, 0
])
crc = self.__calculateCRC(data, len(data) - 2, 0)
crcLSB = crc & 0xFF
crcMSB = (crc & 0xFF00) >> 8
data[6] = crcLSB
data[7] = crcMSB
self.__ser.write(data)
bytes_to_read = 8
data = self.__ser.read(bytes_to_read)
b = bytearray(data)
data = b
#Check for Exception
if (len(data) < bytes_to_read):
raise Exceptions.TimeoutError('Read timeout Exception')
if ((data[1] == 0x86) & (data[2] == 0x01)):
raise Exceptions.function_codeNotSupportedException(
"Function code not supported by master")
if ((data[1] == 0x86) & (data[2] == 0x02)):
raise Exceptions.starting_addressInvalidException(
"Register address invalid")
if ((data[1] == 0x86) & (data[2] == 0x03)):
raise Exceptions.QuantityInvalidException(
"Invalid Register Value")
if ((data[1] == 0x86) & (data[2] == 0x04)):
raise Exceptions.ModbusException("error reading")
crc = self.__calculateCRC(data, len(data) - 2, 0)
crcLSB = crc & 0xFF
crcMSB = (crc & 0xFF00) >> 8
if ((crcLSB != data[len(data) - 2]) &
(crcMSB != data[len(data) - 1])):
raise Exceptions.CRCCheckFailedException("CRC check failed")
if data[1] == self.__unitIdentifier:
return True
else:
return False
else:
protocolIdentifierLSB = 0x00
protocolIdentifierMSB = 0x00
length_lsb = 0x06
length_msb = 0x00
data = bytearray([
transaction_identifier_msb, transaction_identifier_lsb,
protocolIdentifierMSB, protocolIdentifierLSB, length_msb,
length_lsb, self.__unitIdentifier, function_code,
starting_address_msb, starting_address_lsb, valueMSB, valueLSB
])
self.__tcpClientSocket.send(data)
bytes_to_read = 12
self.__receivedata = bytearray()
try:
while (len(self.__receivedata) == 0):
pass
except Exception:
raise Exception('Read Timeout')
data = bytearray(self.__receivedata)
if ((data[1 + 6] == 0x86) & (data[2 + 6] == 0x01)):
raise Exceptions.function_codeNotSupportedException(
"Function code not supported by master")
if ((data[1 + 6] == 0x86) & (data[2 + 6] == 0x02)):
raise Exceptions.starting_addressInvalidException(
"Register address invalid")
if ((data[1 + 6] == 0x86) & (data[2 + 6] == 0x03)):
raise Exceptions.QuantityInvalidException(
"Invalid Register Value")
if ((data[1 + 6] == 0x86) & (data[2 + 6] == 0x04)):
raise Exceptions.ModbusException("error reading")
return True
def write_multiple_registers(self, starting_address, values):
"""
Write multiple registers to Master device (Function code 16)
starting_address: First register to be written
values: Register Values [0..quantity-1] to be written
"""
self.__transactionIdentifier += 1
if (self.__ser is not None):
if (self.__ser.closed):
raise Exception.SerialPortNotOpenedException(
"serial port not opened")
function_code = 16
length = 6
transaction_identifier_lsb = self.__transactionIdentifier & 0xFF
transaction_identifier_msb = (
(self.__transactionIdentifier & 0xFF00) >> 8)
length_lsb = length & 0xFF
length_msb = (length & 0xFF00) >> 8
starting_address_lsb = starting_address & 0xFF
starting_address_msb = (starting_address & 0xFF00) >> 8
quantityLSB = len(values) & 0xFF
quantityMSB = (len(values) & 0xFF00) >> 8
valueToWrite = list()
for i in range(0, len(values)):
valueToWrite.append(values[i])
if (self.__ser is not None):
data = bytearray([
self.__unitIdentifier, function_code, starting_address_msb,
starting_address_lsb, quantityMSB, quantityLSB
])
data.append(len(valueToWrite) * 2) #Bytecount
for i in range(0, len(valueToWrite)):
data.append((valueToWrite[i] & 0xFF00) >> 8)
data.append(valueToWrite[i] & 0xFF)
crc = self.__calculateCRC(data, len(data), 0)
crcLSB = crc & 0xFF
crcMSB = (crc & 0xFF00) >> 8
data.append(crcLSB)
data.append(crcMSB)
self.__ser.write(data)
bytes_to_read = 8
data = self.__ser.read(bytes_to_read)
b = bytearray(data)
data = b
if (len(data) < bytes_to_read):
raise Exceptions.TimeoutError('Read timeout Exception')
if ((data[1] == 0x90) & (data[2] == 0x01)):
raise Exceptions.function_codeNotSupportedException(
"Function code not supported by master")
if ((data[1] == 0x90) & (data[2] == 0x02)):
raise Exceptions.starting_addressInvalidException(
"Starting address invalid or starting address + quantity invalid"
)
if ((data[1] == 0x90) & (data[2] == 0x03)):
raise Exceptions.QuantityInvalidException("quantity invalid")
if ((data[1] == 0x90) & (data[2] == 0x04)):
raise Exceptions.ModbusException("error reading")
crc = self.__calculateCRC(data, len(data) - 2, 0)
crcLSB = crc & 0xFF
crcMSB = (crc & 0xFF00) >> 8
if ((crcLSB != data[len(data) - 2]) &
(crcMSB != data[len(data) - 1])):
raise Exceptions.CRCCheckFailedException("CRC check failed")
if data[1] == self.__unitIdentifier:
return True
else:
return False
else:
protocolIdentifierLSB = 0x00
protocolIdentifierMSB = 0x00
length_lsb = 0x06
length_msb = 0x00
data = bytearray([
transaction_identifier_msb, transaction_identifier_lsb,
protocolIdentifierMSB, protocolIdentifierLSB, length_msb,
length_lsb, self.__unitIdentifier, function_code,
starting_address_msb, starting_address_lsb, quantityMSB,
quantityLSB
])
data.append(len(valueToWrite) * 2) #Bytecount
for i in range(0, len(valueToWrite)):
data.append((valueToWrite[i] & 0xFF00) >> 8)
data.append(valueToWrite[i] & 0xFF)
self.__tcpClientSocket.send(data)
bytes_to_read = 12
self.__receivedata = bytearray()
try:
while (len(self.__receivedata) == 0):
pass
except Exception:
raise Exception('Read Timeout')
data = bytearray(self.__receivedata)
if ((data[1] == 0x90) & (data[2] == 0x01)):
raise Exceptions.function_codeNotSupportedException(
"Function code not supported by master")
if ((data[1] == 0x90) & (data[2] == 0x02)):
raise Exceptions.starting_addressInvalidException(
"Starting address invalid or starting address + quantity invalid"
)
if ((data[1] == 0x90) & (data[2] == 0x03)):
raise Exceptions.QuantityInvalidException("quantity invalid")
if ((data[1] == 0x90) & (data[2] == 0x04)):
raise Exceptions.ModbusException("error reading")
return True
def read_inputregisters(self, starting_address, quantity):
"""
Read Input Registers from Master device (Function code 4)
starting_address : First input register to be read
quantity: Number of input registers to be read
returns: Int Array [0..quantity-1] which contains the input registers
"""
self.__transactionIdentifier += 1
if (self.__ser is not None):
if (self.__ser.closed):
raise Exception.SerialPortNotOpenedException(
"serial port not opened")
if (starting_address > 65535) | (quantity > 125):
raise ValueError(
"Starting address must be 0 - 65535; quantity must be 0 - 125")
function_code = 4
length = 6
transaction_identifier_lsb = self.__transactionIdentifier & 0xFF
transaction_identifier_msb = (
(self.__transactionIdentifier & 0xFF00) >> 8)
length_lsb = length & 0xFF
length_msb = (length & 0xFF00) >> 8
starting_address_lsb = starting_address & 0xFF
starting_address_msb = (starting_address & 0xFF00) >> 8
quantity_lsb = quantity & 0xFF
quantity_msb = (quantity & 0xFF00) >> 8
if (self.__ser is not None):
data = bytearray([
self.__unitIdentifier, function_code, starting_address_msb,
starting_address_lsb, quantity_msb, quantity_lsb, 0, 0
])
crc = self.__calculateCRC(data, len(data) - 2, 0)
crcLSB = crc & 0xFF
crcMSB = (crc & 0xFF00) >> 8
data[6] = crcLSB
data[7] = crcMSB
self.__ser.write(data)
bytes_to_read = 5 + int(quantity * 2)
data = self.__ser.read(bytes_to_read)
b = bytearray(data)
data = b
if (len(data) < bytes_to_read):
raise Exceptions.TimeoutError("Read timeout Exception")
if ((data[1] == 0x84) & (data[2] == 0x01)):
raise Exceptions.function_codeNotSupportedException(
"Function code not supported by master")
if ((data[1] == 0x84) & (data[2] == 0x02)):
raise Exceptions.starting_addressInvalidException(
"Starting address invalid or starting address + quantity invalid"
)
if ((data[1] == 0x84) & (data[2] == 0x03)):
raise Exceptions.QuantityInvalidException("quantity invalid")
if ((data[1] == 0x84) & (data[2] == 0x04)):
raise Exceptions.ModbusException("error reading")
crc = self.__calculateCRC(data, len(data) - 2, 0)
crcLSB = crc & 0xFF
crcMSB = (crc & 0xFF00) >> 8
if ((crcLSB != data[len(data) - 2]) &
(crcMSB != data[len(data) - 1])):
raise Exceptions.CRCCheckFailedException("CRC check failed")
myList = list()
for i in range(0, quantity):
myList.append((data[i * 2 + 3] << 8) + data[i * 2 + 4])
return myList
else:
protocolIdentifierLSB = 0x00
protocolIdentifierMSB = 0x00
length_lsb = 0x06
length_msb = 0x00
data = bytearray([
transaction_identifier_msb, transaction_identifier_lsb,
protocolIdentifierMSB, protocolIdentifierLSB, length_msb,
length_lsb, self.__unitIdentifier, function_code,
starting_address_msb, starting_address_lsb, quantity_msb,
quantity_lsb
])
self.__tcpClientSocket.send(data)
bytes_to_read = 9 + int(quantity * 2)
self.__receivedata = bytearray()
try:
while (len(self.__receivedata) == 0):
pass
except Exception:
raise Exception('Read Timeout')
data = bytearray(self.__receivedata)
if ((data[1 + 6] == 0x84) & (data[2 + 6] == 0x01)):
raise Exceptions.function_codeNotSupportedException(
"Function code not supported by master")
if ((data[1 + 6] == 0x84) & (data[2 + 6] == 0x02)):
raise Exceptions.starting_addressInvalidException(
"Starting address invalid or starting address + quantity invalid"
)
if ((data[1 + 6] == 0x84) & (data[2 + 6] == 0x03)):
raise Exceptions.QuantityInvalidException("quantity invalid")
if ((data[1 + 6] == 0x84) & (data[2 + 6] == 0x04)):
raise Exceptions.ModbusException("error reading")
myList = list()
for i in range(0, quantity):
myList.append((data[i * 2 + 3 + 6] << 8) + data[i * 2 + 4 + 6])
return myList