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.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
[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:
error_code = self.client.last_error()
raise ExecutionError('Could not write coil (code={})'.format(error_code))
[docs] @Driver.check_active
def get(self):
status = self.client.read_coils(self.coil.coil)
if status is None:
error_code = self.client.last_error()
raise ExecutionError('Could not read coil (code={})'.format(error_code))
status = status[0]
if self.coil.invert:
status = not status
return status