Modbus-VFD/model.py at main · ShopBotTools/Modbus-VFD · GitHub

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import threading
import minimalmodbus
import modbus_settings as MB
import user_inputs

lock = threading.Lock()

class VFDModel:
    def __init__(self, com_port):
        self.connected = False
        # Create "instrument" that can perform read and write
        # operations and import its settings from the modbus settings module
        try:
            self.vfd = minimalmodbus.Instrument(com_port, MB.MB_ADDRESS)
            self.vfd.mode = minimalmodbus.MODE_RTU
            self.vfd.serial.parity = minimalmodbus.serial.PARITY_NONE
            self.vfd.serial.baudrate = MB.BAUDRATE
            self.vfd.serial.bytesize = MB.BYTESIZE
            self.vfd.serial.stopbits = MB.STOPBITS
            self.vfd.serial.timeout = MB.TIMEOUT
            self.vfd.clear_buffers_before_each_transaction = MB.CLEAR_BUFFERS_BEFORE_CALL
            self.vfd.close_port_after_each_call = MB.CLEAR_BUFFERS_AFTER_CALL
            self.vfd.debug = MB.DEBUG
            self.connected = True
        except minimalmodbus.ModbusException as e:
            # Handle modbus communication error
            print("Modbus Exception:", e)
        except PermissionError as e:
            # Handle permission error
            print("Permission Error:", e)
        except Exception as e:
            # Handle other exceptions
            print("Exception:", e)
            self.connected = False

    def write_VFD(self, user_input, entry_to_change):
        speed_set = False
        if self.connected:
            if entry_to_change == "frequency":
                speed_package = user_inputs.set_user_frequency(user_input)
            elif entry_to_change == "spindle":
                speed_package = user_inputs.set_user_spindle(user_input)
            if speed_package != "NaN" and speed_package != "OL":
                speed_set = True
            else:
                return False

        ## Send the request to the VFD
        def send_to_vfd(register, data, function_code, decimals=0, signed=False):
            if self.connected:
                with lock:
                    try:
                        self.vfd.write_register(register, data, decimals, function_code, signed)
                    except minimalmodbus.ModbusException as e:
                        # Handle modbus communication error
                        print("Modbus Exception:", e)
                    except PermissionError as e:
                        # Handle permission error
                        print("Permission Error:", e)
                    except Exception as e:
                        # Handle other exceptions
                        print("Exception:", e)

        # If the speed has been set correctly then pass on the speed package as
        # well as the register position to the function to send to the VFD
        if speed_set:
#            print("Attempting unlock drive")
            send_to_vfd(MB.UNLOCK_DRIVE, MB.PASSWORD, MB.WRITE_SINGLE_REGISTER)
#            print("Attempting unlock parameters")
            send_to_vfd(MB.UNLOCK_PARAMETERS, MB.PASSWORD, MB.WRITE_SINGLE_REGISTER)
#            print("Attempting set frequency")
            send_to_vfd(MB.SET_FREQUENCY, speed_package, MB.WRITE_SINGLE_REGISTER)
#            print("Attempting to set security bit to true")
            send_to_vfd(MB.COMMAND_DRIVE, MB.COMMAND_DRIVE_SECURITY_BIT, MB.WRITE_SINGLE_REGISTER)
            # DEBUG so that command prompt does not immediately disappear
            # input()
        return True

    def read_VFD(self, register, read_length):
        # Read data from the device
        if self.connected:
            with lock:
                try:
                    # Read data from the device
                    data = self.vfd.read_registers(register, read_length, MB.READ_REGISTER)
                    return data

                except minimalmodbus.ModbusException as e:
                    # Handle modbus communication error
                    print("Modbus Exception:", e)
                except PermissionError as e:
                    # Handle permission error
                    print("Permission Error:", e)
                except Exception as e:
                    # Handle other exceptions
                    print("Exception:", e)