PLC Simulator

This project provides an extensible PLC simulation environment. The MemoryManager provides a configurable linear memory space that is independent of any particular model of PLC. The IoManager supports a number of simulation functions that can be specified to update memory locations in the MemoryManager's memory space. The FieldbusManager instantiates configured fieldbus-specific objects that simulate the request/response protocols of PLCs. The fieldbus-specific object to handle incoming requests is mapped by TCP listening port. The Listener provides a TCP/IP interface with which clients, such as the plc-data-server (PDS), can connect and query simulated PLCs.

See the API documentation for further details of each of the simulator's components.

Install

The package can be installed from PyPI (note the package distribution name):

$ pip install plc-simulator

Running the application

The general usage is to call the plcsimulator package main followed by a configuration file. As a convenience, the package installs a console script called plcsimulator that wraps the call to the package main. Thus the following two command line invocations are identical:

$ python -m plcsimulator plc-simulator-conf.json
$ plcsimulator plc-simulator-conf.json

Specifying the --help option, will print the CLI usage and quit:

$ python -m plcsimulator --help 

The configuration

The configuration contains sections that map to components of the simulator. These sections specify:

• listener: Socket connection parameters such as host and port.
• fieldbus_manager: A list of available fieldbus-specific modules. Each module configuration in the list specifies:
  • The module and class that provides the fieldbus interface.
  • The TCP port number that maps to the corresponding one specified in the listener configuration.
  • (Optional) Static configuration used when instantiating the fieldbus object.
• memory_manager: The size of the required memory space sections.
  • blen: The number of bits in the bits section. This should be a multiple of 8 and will be rounded up to be so if necessary.
  • w16len: The number of 16-bit words in the words16 section.
  • w32len: The number of 32-bit words in the words32 section.
  • w64len: The number of 64-bit words in the words64 section.
• io_manager: A list of simulations to run. What is specified for each simulation configuration depends on the simulation function, but typically includes:
  • id: (Optional) A meaningful label which is included in logging output.
  • memspace: The memory space section name, starting address, and number of references (nbits for bits section, nwords for words* sections) that the simulation should read/write to.
  • source: (Optional) Some simulations require the value from a source memspace configuration to act as an input to the simulation function.
  • operands: (Optional) The operation function-type simulation requires a list of operands. An operand can either be a constant value or the value from a source memspace configuration. The operator name must be an operator from the Python operator library.
  • function: The function type and any static parameters.
  • pause: Time (s) to pause between calls of the simulation.
• logging: A Python logging configuration, provided as input to logging.config.dictConfig().

An example configuration

The following example configuration shows most of the available options:

{
    "listener": {
        "host": "localhost",
        "port": 5555,
        "backlog": 10
    },
    "fieldbus_manager": {
        "modules": [
            {
                "module": "plcsimulator.ModbusModule",
                "class": "ModbusModule",
                "id": "modbus",
                "port": 5555,
                "conf": {}
            }
        ]
    },
    "memory_manager": {
        "memspace": {
            "blen": 64,
            "w16len": 800,
            "w32len": 0,
            "w64len": 0
        }
    },
    "io_manager": {
        "simulations": [
            {
                "memspace": {"section": "words16", "addr": 0, "nwords": 1},
                "function": {"type": "counter"},
                "pause": 0.001
            },
            {
                "memspace": {"section": "words16", "addr": 1, "nwords": 1},
                "function": {"type": "binary"},
                "pause": 5
            },
            {
                "memspace": {"section": "words16", "addr": 2, "nwords": 1},
                "function": {"type": "static", "value": 321},
                "pause": 60
            },
            {
                "memspace": {"section": "words16", "addr": 3, "nwords": 1},
                "function": {"type": "sine"},
                "pause": 0.001
            },
            {
                "memspace": {"section": "words16", "addr": 4, "nwords": 1},
                "function": {"type": "cosine"},
                "pause": 0.001
            },
            {
                "memspace": {"section": "words16", "addr": 5, "nwords": 1},
                "function": {"type": "sawtooth"},
                "pause": 0.001
            },
            {
                "memspace": {"section": "words16", "addr": 6, "nwords": 1},
                "function": {"type": "square"},
                "pause": 0.001
            },
            {
                "id": "range_counter",
                "memspace": {"section": "words16", "addr": 7, "nwords": 1},
                "function": {"type": "counter", "range": [10]},
                "pause": 0.1
            },
            {
                "id": "dec_range_counter",
                "memspace": {"section": "words16", "addr": 8, "nwords": 1},
                "function": {"type": "counter", "range": [10, 0]},
                "pause": 0.1
            },
            {
                "id": "step_range_counter",
                "memspace": {"section": "words16", "addr": 9, "nwords": 1},
                "function": {"type": "counter", "range": [0, 10, 2]},
                "pause": 0.1
            },
            {
                "id": "randrange",
                "memspace": {"section": "words16", "addr": 10, "nwords": 1},
                "function": {"type": "randrange", "range": [50, 61]},
                "pause": 1
            },
            {
                "id": "lognormal",
                "memspace": {"section": "words16", "addr": 11, "nwords": 1},
                "function": {"type": "lognormal"},
                "pause": 1
            },
            {
                "id": "uniform",
                "memspace": {"section": "words16", "addr": 12, "nwords": 1},
                "function": {"type": "uniform"},
                "pause": 1
            },
            {
                "id": "copy_source_0",
                "memspace": {"section": "words16", "addr": 13, "nwords": 1},
                "function": {"type": "binary"},
                "pause": 15
            },
            {
                "id": "copy_source_1",
                "memspace": {"section": "words16", "addr": 14, "nwords": 1},
                "function": {"type": "binary"},
                "pause": 60
            },
            {
                "id": "copy_source_2",
                "memspace": {"section": "words16", "addr": 15, "nwords": 1},
                "function": {"type": "binary"},
                "pause": 20
            },
            {
                "id": "copy_source_3",
                "memspace": {"section": "words16", "addr": 16, "nwords": 1},
                "function": {"type": "counter", "range": [80, 0]},
                "pause": 1
            },
            {
                "id": "copy_dest",
                "memspace": {"section": "words16", "addr": 20, "nwords": 4},
                "source": {
                    "memspace": {"section": "words16", "addr": 13, "nwords": 4}
                },
                "function": {"type": "copy"},
                "pause": 1
            },
            {
                "id": "transform_on",
                "memspace": {"section": "words16", "addr": 24, "nwords": 1},
                "source": {
                    "memspace": {"section": "words16", "addr": 16, "nwords": 1}
                },
                "function": {"type": "transform",
                             "transform": {"in": [0, 10], "out": 1}
                },
                "pause": 1
            },
            {
                "id": "transform_off",
                "memspace": {"section": "words16", "addr": 24, "nwords": 1},
                "source": {
                    "memspace": {"section": "words16", "addr": 16, "nwords": 1}
                },
                "function": {"type": "transform",
                             "transform": {"in": [11, 80], "out": 0}
                },
                "pause": 1
            },
            {
                "id": "op_arg_a",
                "memspace": {"section": "words16", "addr": 30, "nwords": 1},
                "function": {"type": "counter", "range": [1, 11]},
                "pause": 1
            },
            {
                "id": "op_arg_b",
                "memspace": {"section": "words16", "addr": 31, "nwords": 1},
                "function": {"type": "counter", "range": [1, 11]},
                "pause": 1
            },
            {
                "id": "op_add",
                "memspace": {"section": "words16", "addr": 32, "nwords": 1},
                "operands": [
                    {"memspace": {"section": "words16", "addr": 30, "nwords": 1}},
                    {"memspace": {"section": "words16", "addr": 31, "nwords": 1}}
                ],
                "function": {"type": "operation", "operator": "add"},
                "pause": 0.5
            },
            {
                "id": "op_floordiv",
                "memspace": {"section": "words16", "addr": 33, "nwords": 1},
                "operands": [
                    {"memspace": {"section": "words16", "addr": 30, "nwords": 1}},
                    {"value": 2}
                ],
                "function": {"type": "operation", "operator": "floordiv"},
                "pause": 0.5
            },
            {
                "id": "byte_0_bit_0_flip",
                "memspace": {"section": "bits", "addr": 0, "nbits": 1},
                "function": {"type": "binary"},
                "pause": 5
            },
            {
                "id": "byte_0_bit_1_flip",
                "memspace": {"section": "bits", "addr": 1, "nbits": 1},
                "function": {"type": "binary"},
                "pause": 2
            },
            {
                "id": "byte_1_fixed_bits_0_to_2",
                "memspace": {"section": "bits", "addr": 8, "nbits": 8},
                "function": {"type": "static", "value": 7},
                "pause": 60
            },
            {
                "id": "byte_2_range_counter_cycling_bits",
                "memspace": {"section": "bits", "addr": 16, "nbits": 8},
                "function": {"type": "counter", "range": [255]},
                "pause": 0.1
            }
        ]
    },
    "logging": {
        "version": 1,
        "handlers": {
            "file": {
                "class": "logging.FileHandler",
                "filename": "/dev/null",
                "mode": "a",
                "formatter": "default"
            },
            "console": {
                "class": "logging.StreamHandler",
                "formatter": "brief"
            }
        },
        "root": {
            "level": "INFO",
            "handlers": ["console", "file"]
        },
        "formatters": {
            "default": {
                "format": "%(asctime)s %(levelname)s %(threadName)s %(message)s",
                "datefmt": "%Y-%m-%dT%H:%M:%S"
            },
            "brief": {
                "format": "%(levelname)s %(threadName)s %(message)s"
            }
        }
    }
}