Source code for labgrid.driver.modbusdriver

from importlib import import_module
import attr

from ..factory import target_factory
from ..protocol import DigitalOutputProtocol
from ..util.proxy import proxymanager
from .common import Driver
from .exception import ExecutionError

[docs]@target_factory.reg_driver @attr.s(eq=False) class ModbusCoilDriver(Driver, DigitalOutputProtocol): bindings = {"coil": "ModbusTCPCoil", }
[docs] def __attrs_post_init__(self): super().__attrs_post_init__() self._module = import_module('pyModbusTCP.client') self._consts = import_module('pyModbusTCP.constants') self.client = None
[docs] def on_activate(self): # we can only forward if the backend knows which port to use host, port = proxymanager.get_host_and_port(self.coil, default_port=502) self.client = self._module.ModbusClient( host=host, port=int(port), auto_open=True, auto_close=True)
[docs] def on_deactivate(self): self.client = None
def _handle_error(self, action): error_code = self.client.last_error() if error_code == self._consts.MB_EXCEPT_ERR: exc = self.client.last_except() if exc not in [self._consts.EXP_ACKNOWLEDGE, self._consts.EXP_NONE]: raise ExecutionError( f'Could not {action} coil (code={error_code}/exception={exc})') raise ExecutionError(f'Could not {action} coil (code={error_code})')
[docs] @Driver.check_active def set(self, status): if self.coil.invert: status = not status write_status = self.client.write_single_coil(self.coil.coil, bool(status)) if write_status is None: self._handle_error("write")
[docs] @Driver.check_active def get(self): status = self.client.read_coils(self.coil.coil) if status is None: self._handle_error("read") status = status[0] if self.coil.invert: status = not status return status