hvl_ccb.dev.mbw973.mbw973

Device class for controlling a MBW 973 SF6 Analyzer over a serial connection.

The MBW 973 is a gas analyzer designed for gas insulated switchgear and measures humidity, SF6 purity and SO2 contamination in one go. Manufacturer homepage: https://www.mbw.ch/products/sf6-gas-analysis/973-sf6-analyzer/

class MBW973(com, dev_config=None)

Bases: SingleCommDevice

MBW 973 dew point mirror device class.

static config_cls()

Return the default configdataclass class.

Returns:

a reference to the default configdataclass class

static default_com_cls()

Get the class for the default communication protocol used with this device.

Returns:

the type of the standard communication protocol for this device

is_done() → bool

Poll status of the dew point mirror and return True, if all measurements are done.

Returns:

True, if all measurements are done; False otherwise.

Raises:

SerialCommunicationIOError – when communication port is not opened

read(cast_type: type = <class 'str'>)

Read value from self.com and cast to cast_type. Raises ValueError if read text (str) is not convertible to cast_type, e.g. to float or to int.

Returns:

Read value of cast_type type.

read_float() → float

Convenience wrapper for self.read(), with typing hint for return value.

Returns:

Read float value.

read_int() → int

Convenience wrapper for self.read(), with typing hint for return value.

Returns:

Read int value.

read_measurements() → dict[str, float]

Read out measurement values and return them as a dictionary.

Returns:

Dictionary with values.

Raises:

SerialCommunicationIOError – when communication port is not opened

set_measuring_options(humidity: bool = True, sf6_purity: bool = False) → None

Send measuring options to the dew point mirror.

Parameters:

• humidity – Perform humidity test or not?

• sf6_purity – Perform SF6 purity test or not?

Raises:

SerialCommunicationIOError – when communication port is not opened

start() → None

Start this device. Opens the communication protocol and retrieves the set measurement options from the device.

Raises:

SerialCommunicationIOError – when communication port cannot be opened.

start_control() → None

Start dew point control to acquire a new value set.

Raises:

SerialCommunicationIOError – when communication port is not opened

stop() → None

Stop the device. Closes also the communication protocol.

write(value) → None

Send value to self.com.

Parameters:

value – Value to send, converted to str.

Raises:

SerialCommunicationIOError – when communication port is not opened

class MBW973Config(polling_interval: int | float = 2)

Bases: object

Device configuration dataclass for MBW973.

clean_values()

force_value(fieldname, value)

Forces a value to a dataclass field despite the class being frozen.

NOTE: you can define post_force_value method with same signature as this method to do extra processing after value has been forced on fieldname.

Parameters:

• fieldname – name of the field

• value – value to assign

is_configdataclass = True

classmethod keys() → Sequence[str]

Returns a list of all configdataclass fields key-names.

Returns:

a list of strings containing all keys.

classmethod optional_defaults() → dict[str, object]

Returns a list of all configdataclass fields, that have a default value assigned and may be optionally specified on instantiation.

Returns:

a list of strings containing all optional keys.

polling_interval: int | float = 2

Polling period for is_done status queries [in seconds].

classmethod required_keys() → Sequence[str]

Returns a list of all configdataclass fields, that have no default value assigned and need to be specified on instantiation.

Returns:

a list of strings containing all required keys.

exception MBW973ControlRunningError

Bases: MBW973Error

Error indicating there is still a measurement running, and a new one cannot be started.

exception MBW973Error

Bases: DeviceError

General error with the MBW973 dew point mirror device.

exception MBW973PumpRunningError

Bases: MBW973Error

Error indicating the pump of the dew point mirror is still recovering gas, unable to start a new measurement.

class MBW973SerialCommunication(configuration)

Bases: SerialCommunication

Specific communication protocol implementation for the MBW973 dew point mirror. Already predefines device-specific protocol parameters in config.

static config_cls()

Return the default configdataclass class.

Returns:

a reference to the default configdataclass class

class MBW973SerialCommunicationConfig(terminator: bytes = b'\r', encoding: str = 'utf-8', encoding_error_handling: str = 'strict', wait_sec_read_text_nonempty: Union[int, float] = 0.5, default_n_attempts_read_text_nonempty: int = 10, port: Optional[str] = None, baudrate: int = 9600, parity: Union[str, hvl_ccb.comm.serial.SerialCommunicationParity] = <SerialCommunicationParity.NONE: 'N'>, stopbits: Union[int, hvl_ccb.comm.serial.SerialCommunicationStopbits] = <SerialCommunicationStopbits.ONE: 1>, bytesize: Union[int, hvl_ccb.comm.serial.SerialCommunicationBytesize] = <SerialCommunicationBytesize.EIGHTBITS: 8>, timeout: Union[int, float] = 3)

Bases: SerialCommunicationConfig

baudrate: int = 9600

Baudrate for MBW973 is 9600 baud

bytesize: int | SerialCommunicationBytesize = 8

One byte is eight bits long

force_value(fieldname, value)

Forces a value to a dataclass field despite the class being frozen.

NOTE: you can define post_force_value method with same signature as this method to do extra processing after value has been forced on fieldname.

Parameters:

• fieldname – name of the field

• value – value to assign

classmethod keys() → Sequence[str]

Returns a list of all configdataclass fields key-names.

Returns:

a list of strings containing all keys.

classmethod optional_defaults() → dict[str, object]

Returns a list of all configdataclass fields, that have a default value assigned and may be optionally specified on instantiation.

Returns:

a list of strings containing all optional keys.

parity: str | SerialCommunicationParity = 'N'

MBW973 does not use parity

classmethod required_keys() → Sequence[str]

Returns a list of all configdataclass fields, that have no default value assigned and need to be specified on instantiation.

Returns:

a list of strings containing all required keys.

stopbits: int | SerialCommunicationStopbits = 1

MBW973 does use one stop bit

terminator: bytes = b'\r'

The terminator is only CR

timeout: int | float = 3

use 3 seconds timeout as default