109 lines
4.0 KiB
Python
109 lines
4.0 KiB
Python
from pymodbus.exceptions import NotImplementedException
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from pymodbus.interfaces import IModbusSlaveContext
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#---------------------------------------------------------------------------#
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# Logging
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#---------------------------------------------------------------------------#
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import logging
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_logger = logging.getLogger(__name__)
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#---------------------------------------------------------------------------#
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# Context
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#---------------------------------------------------------------------------#
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class RemoteSlaveContext(IModbusSlaveContext):
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''' TODO
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This creates a modbus data model that connects to
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a remote device (depending on the client used)
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'''
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def __init__(self, client, unit=None):
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''' Initializes the datastores
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:param client: The client to retrieve values with
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:param unit: Unit ID of the remote slave
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'''
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self._client = client
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self.unit = unit
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self.__build_mapping()
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def reset(self):
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''' Resets all the datastores to their default values '''
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raise NotImplementedException()
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def validate(self, fx, address, count=1):
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''' Validates the request to make sure it is in range
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:param fx: The function we are working with
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:param address: The starting address
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:param count: The number of values to test
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:returns: True if the request in within range, False otherwise
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'''
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_logger.debug("validate[%d] %d:%d" % (fx, address, count))
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result = self.__get_callbacks[self.decode(fx)](address, count)
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return not result.isError()
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def getValues(self, fx, address, count=1):
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''' Get `count` values from datastore
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:param fx: The function we are working with
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:param address: The starting address
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:param count: The number of values to retrieve
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:returns: The requested values from a:a+c
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'''
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# TODO deal with deferreds
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_logger.debug("get values[%d] %d:%d" % (fx, address, count))
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result = self.__get_callbacks[self.decode(fx)](address, count)
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return self.__extract_result(self.decode(fx), result)
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def setValues(self, fx, address, values):
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''' Sets the datastore with the supplied values
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:param fx: The function we are working with
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:param address: The starting address
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:param values: The new values to be set
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'''
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# TODO deal with deferreds
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_logger.debug("set values[%d] %d:%d" % (fx, address, len(values)))
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self.__set_callbacks[self.decode(fx)](address, values)
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def __str__(self):
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''' Returns a string representation of the context
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:returns: A string representation of the context
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'''
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return "Remote Slave Context(%s)" % self._client
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def __build_mapping(self):
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'''
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A quick helper method to build the function
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code mapper.
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'''
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kwargs = {}
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if self.unit:
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kwargs["unit"] = self.unit
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self.__get_callbacks = {
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'd': lambda a, c: self._client.read_discrete_inputs(a, c, **kwargs),
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'c': lambda a, c: self._client.read_coils(a, c, **kwargs),
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'h': lambda a, c: self._client.read_holding_registers(a, c, **kwargs),
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'i': lambda a, c: self._client.read_input_registers(a, c, **kwargs),
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}
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self.__set_callbacks = {
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'd': lambda a, v: self._client.write_coils(a, v, **kwargs),
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'c': lambda a, v: self._client.write_coils(a, v, **kwargs),
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'h': lambda a, v: self._client.write_registers(a, v, **kwargs),
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'i': lambda a, v: self._client.write_registers(a, v, **kwargs),
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}
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def __extract_result(self, fx, result):
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''' A helper method to extract the values out of
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a response. TODO make this consistent (values?)
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'''
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if not result.isError():
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if fx in ['d', 'c']:
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return result.bits
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if fx in ['h', 'i']:
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return result.registers
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else:
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return result
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