Pymodbus in pyscada

[singhaisid0]

I am not getting functionality of following program which is using pymodbus library. Please can anubody help me in this `# -- coding: utf-8 --   | from pyscada import log   |     | try:   | from pymodbus.client.sync import ModbusTcpClient   | from pymodbus.client.sync import ModbusSerialClient   | from pymodbus.client.sync import ModbusUdpClient   | from pymodbus.constants import Defaults   | driver_ok = True   | except ImportError:   | driver_ok = False   |     | from math import isnan, isinf   | from time import time   | import traceback   |     | def find_gap(self,L,value):   | """   | try to find a address gap in the list of modbus registers   | """   | for index in range(len(L)):   | if L[index] == value:   | return None   | if L[index] > value:   | return index   |     |     | def _default_decoder(value):   | return value[0]   |     |     | class RegisterBlock:   | def init(self):   | self.registers_data = {} # dict of modbus register addresses   | self.registers = []   | self.variables = {}   | self.register_size = 16 # in bits   |     |     | def insert_item(self,variable_id,variable_address,decode_value=_default_decoder,variable_length=1):   | self.variables[variable_id]= {   | 'decode_function':decode_value,\   | 'len':variable_length,\   | 'registers': []\   | }   | for idx in range(variable_length/self.register_size):   | if not self.registers_data.has_key(variable_address+idx):   | # register will not be queried add register   | self.registers_data[variable_address+idx] = None   |     | self.variables[variable_id]['registers'].append(variable_address+idx)   | self.registers = self.registers_data.keys()   | self.registers.sort()   |     | def check(self):   | '''   | check the registerblock   | '''   | # todo do check for gaps   | return True   |     | def _request_data(self,slave,unit,first_address,quantity):   | return slave.read_input_registers(first_address,quantity,unit=unit)   |     | def request_data(self,slave,unit=0x00):   | quantity = max(self.registers)-min(self.registers)+1   | first_address = min(self.registers)   |     | try:   | result = self._request_data(slave,unit,first_address,quantity)   | except:   | # something went wrong (ie. Server/Slave is not excessible)   | # todo add log for some specific errors   | #var = traceback.format_exc()   | #log.error("exeption while request_data of %s" % (var))   | return None   | if hasattr(result, 'registers'):   | return self.decode_data(result.registers)   | elif hasattr(result, 'bits'):   | return self.decode_data(result.bits)   | else:   | return None   |     |     | def decode_data(self,result):   | out = {}   | # map result to the register   | for idx in self.registers:   | self.registers_data[idx] = result.pop(0)   | for id in self.variables:   | out[id] = self.variables[id]['decode_function']([self.registers_data[k] for k in self.variables[id]['registers']])   | if type(out[id]) is float:   | if isnan(out[id]) or isinf(out[id]):   | out[id] = None   | return out   |     | class InputRegisterBlock(RegisterBlock):   | def _request_data(self,slave,unit,first_address,quantity):   | return slave.read_input_registers(first_address,quantity,unit=unit)   |     |     | class HoldingRegisterBlock(RegisterBlock):   | def _request_data(self,slave,unit,first_address,quantity):   | return slave.read_holding_registers(first_address,quantity,unit=unit)   |     |     | class CoilBlock(RegisterBlock):   | def init(self):   | RegisterBlock.init(self)   | self.register_size = 1 # in bitss   |     | def _request_data(self,slave,unit,first_address,quantity):   | return slave.read_coils(first_address,quantity,unit=unit)   |     |     | class DiscreteInputBlock(RegisterBlock):   | def init(self):   | RegisterBlock.init(self)   | self.register_size = 1 # in bitss   |     | def _request_data(self,slave,unit,first_address,quantity):   | return slave.read_discrete_inputs(first_address,quantity,unit=unit)   |     |     | class Device:   | """   | Modbus device (Master) class   | """   | def init(self,device):   | self.device = device   | self._address = device.modbusdevice.ip_address   | self._unit_id = device.modbusdevice.unit_id   | self._port = device.modbusdevice.port   | self._protocol = device.modbusdevice.protocol   | self._stopbits = device.modbusdevice.stopbits   | self._bytesize = device.modbusdevice.bytesize   | self._parity = device.modbusdevice.parity   | self._baudrate = device.modbusdevice.baudrate   | self._timeout = device.modbusdevice.timeout   | self._device_not_accessible = 0   | # stopbits   | if self._stopbits == 0:   | self._stopbits = Defaults.Stopbits   | # bytesize   | if self._bytesize == 0:   | self._bytesize = Defaults.Bytesize   | # parity   | parity_list = {0:Defaults.Parity,1:'N',2:'E',3:'O'}   | self._parity = parity_list[self._parity]   | # baudrate   | if self._baudrate == 0:   | self._baudrate = Defaults.Baudrate   | # timeout   | if self._timeout == 0:   | self._timeout = Defaults.Timeout   |     | self.trans_input_registers = []   | self.trans_coils = []   | self.trans_holding_registers = []   | self.trans_discrete_inputs = []   | self.variables = {}   | self._variable_config = self._prepare_variable_config(device)   | self.data = []   |     |     | def _prepare_variable_config(self,device):   |     | for var in device.variable_set.filter(active=1):   | if not hasattr(var,'modbusvariable'):   | continue   | FC = var.modbusvariable.function_code_read   | if FC == 0:   | continue   | #address = var.modbusvariable.address   | #bits_to_read = get_bits_by_class(var.value_class)   |     | #self.variables[var.pk] = {'value_class':var.value_class,'writeable':var.writeable,'record':var.record,'name':var.name,'adr':address,'bits':bits_to_read,'fc':FC}   | # self.variables[var.pk] = RecordData(var.pk,var.name,var.value_class,\   | # var.writeable,adr=address,bits=bits_to_read,fc=FC,accessible=True,\   | # record_value=var.record,scaling = var.scaling)   |     | # add some attr to the var model   | var.add_attr(accessible=1)   | # add the var to the list of   | self.variables[var.pk] = var   |     |     | if FC == 1: # coils   | self.trans_coils.append([var.modbusvariable.address,var.pk,FC])   | elif FC == 2: # discrete inputs   | self.trans_discrete_inputs.append([var.modbusvariable.address,var.pk,FC])   | elif FC == 3: # holding registers   | self.trans_holding_registers.append([var.modbusvariable.address,var.decode_value,var.get_bits_by_class(),var.pk,FC])   | elif FC == 4: # input registers   | self.trans_input_registers.append([var.modbusvariable.address,var.decode_value,var.get_bits_by_class(),var.pk,FC])   | else:   | continue   |     | self.trans_discrete_inputs.sort()   | self.trans_holding_registers.sort()   | self.trans_coils.sort()   | self.trans_input_registers.sort()   | out = []   |     | # input registers   | old = -2   | regcount = 0   | for entry in self.trans_input_registers:   | if (entry[0] != old) or regcount >122:   | regcount = 0   | out.append(InputRegisterBlock()) # start new register block   | out[-1].insert_item(entry[3],entry[0],entry[1],entry[2]) # add item to block   | old = entry[0] + entry[2]/16   | regcount += entry[2]/16   |     | # holding registers   | old = -2   | regcount = 0   | for entry in self.trans_holding_registers:   | if (entry[0] != old) or regcount >122:   | regcount = 0   | out.append(HoldingRegisterBlock()) # start new register block   | out[-1].insert_item(entry[3],entry[0],entry[1],entry[2]) # add item to block   | old = entry[0] + entry[2]/16   | regcount += entry[2]/16   |     | # coils   | old = -2   | for entry in self.trans_coils:   | if (entry[0] != old+1):   | out.append(CoilBlock()) # start new coil block   | out[-1].insert_item(entry[1],entry[0])   | old = entry[0]   | # discrete inputs   | old = -2   | for entry in self.trans_discrete_inputs:   | if (entry[0] != old+1):   | out.append(DiscreteInputBlock()) # start new coil block   | out[-1].insert_item(entry[1],entry[0])   | old = entry[0]   | return out   |     |     | def _connect(self):   | """   | connect to the modbus slave (server)   | """   | if self._protocol == 0: # TCP   | self.slave = ModbusTcpClient(self._address,int(self._port))   | elif self._protocol == 1: # UDP   | self.slave = ModbusUdpClient(self._address,int(self._port))   | elif self._protocol in (2,3,4): # serial   | method_list = {2:'ascii',3:'rtu',4:'binary'}   | self.slave = ModbusSerialClient( \   | method=method_list[self._protocol],\   | port=self._port,\   | stopbits=self._stopbits,\   | bytesize =self._bytesize,\   | parity =self._parity,\   | baudrate =self._baudrate,\   | timeout =self._timeout)   | else:   | raise NotImplementedError, "Protocol not supported"   | status = self.slave.connect()   | return status   |     |     |     | def _disconnect(self):   | """   | close the connection to the modbus slave (server)   | """   | self.slave.close()   |     | def request_data(self):   | """   |     | """   | if not driver_ok:   | return None   | if not self._connect():   | if self._device_not_accessible == -1: #   | log.error("device with id: %d is not accessible"%(self.device.pk))   | self._device_not_accessible -= 1   | return []   | output = []   | for register_block in self._variable_config:   | result = register_block.request_data(self.slave,self._unit_id)   | if result is None:   | self._disconnect()   | self._connect()   | result = register_block.request_data(self.slave,self._unit_id)   |     | if result is not None:   | for variable_id in register_block.variables:   | if self.variables[variable_id].update_value(result[variable_id],time()):   | redorded_data_element = self.variables[variable_id].create_recorded_data_element()   | if redorded_data_element is not None:   | output.append(redorded_data_element)   | if self.variables[variable_id].accessible < 1:   | log.info(("variable with id: %d is now accessible")%(variable_id))   | self.variables[variable_id].accessible = 1   | else:   | for variable_id in register_block.variables:   | if self.variables[variable_id].accessible == -1:   | log.error(("variable with id: %d is not accessible")%(variable_id))   | self.variables[variable_id].update_value(None,time())   | self.variables[variable_id].accessible -= 1   |     | # reset device not accessible status   | if self._device_not_accessible <= -1:   | log.info(("device with id: %d is now accessible")%(self.device.pk))   | if self._device_not_accessible < 1:   | self._device_not_accessible = 1   |     | self._disconnect()   | return output   |     | def write_data(self,variable_id, value):   | """   | write value to single modbus register or coil   | """   | if not self.variables[variable_id].writeable:   | return False   |     | if self.variables[variable_id].modbusvariable.function_code_read == 3:   | # write register   | if 0 <= self.variables[variable_id].modbusvariable.address <= 65535:   |     | if self._connect():   | if self.variables[variable_id].get_bits_by_class()/16 == 1:   | # just write the value to one register   | self.slave.write_register(self.variables[variable_id].modbusvariable.address,int(value),unit=self._unit_id)   | else:   | # encode it first   | self.slave.write_registers(self.variables[variable_id].modbusvariable.address,list(self.variables[variable_id].encode_value(value)),unit=self._unit_id)   | self._disconnect()   | return True   | else:   | log.info(("device with id: %d is now accessible")%(self.device.pk))   | return False   | else:   | log.error('Modbus Address %d out of range'%self.variables[variable_id].modbusvariable.address)   | return False   | elif self.variables[variable_id].modbusvariable.function_code_read == 1:   | # write coil   | if 0 <= self.variables[variable_id].modbusvariable.address <= 65535:   | if self._connect():   | self.slave.write_coil(self.variables[variable_id].modbusvariable.address,bool(value),unit=self._unit_id)   | self._disconnect()   | return True   | else:   | log.info(("device with id: %d is now accessible")%(self.device.pk))   | return False   | else:   | log.error('Modbus Address %d out of range'%self.variables[variable_id].modbusvariable.address)   | else:   | log.error('wrong type of function code %d'%self.variables[variable_id].modbusvariable.function_code_read)   | return False

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[dhoomakethu]

what exactly is the problem ? Please share any error tracebacks if available , also please provide details regarding the pymodbus version.

[singhaisid0]

The following link from where I get this code. Pyscada>modbus>device Actually it's Pyscada program which is using pymodbus library in which I am not getting which type of format it's sending for request to device and which type of format it's getting in reponse. I am using version 1.3.1

[dhoomakethu]

please go through the documentation of pyscada or get in touch with the pyscada maintainers on how to use Modbus with pyscada. Please raise an issue if there is any particular issue with pymodbus .