hvl_ccb.comm.labjack_ljm

Communication protocol for LabJack using the LJM Library. Originally developed and tested for LabJack T7-PRO.

Makes use of the LabJack LJM Library Python wrapper. This wrapper needs an installation of the LJM Library for Windows, Mac OS X or Linux. Go to: https://labjack.com/support/software/installers/ljm and https://labjack.com/support/software/examples/ljm/python

class LJMCommunication(configuration)

Bases: CommunicationProtocol

Communication protocol implementing the LabJack LJM Library Python wrapper.

close() → None

Close the communication port.

static config_cls()

Return the default configdataclass class.

Returns:

a reference to the default configdataclass class

property is_open: bool

Flag indicating if the communication port is open.

Returns:

True if the port is open, otherwise False

open() → None

Open the communication port.

read_name(*names: str, return_num_type: type[~numbers.Real] = <class 'float'>) → Real | Sequence[Real]

Read one or more input numeric values by name.

Parameters:

• names – one or more names to read out from the LabJack

• return_num_type – optional numeric type specification for return values; by default float.

Returns:

answer of the LabJack, either single number or multiple numbers in a sequence, respectively, when one or multiple names to read were given

Raises:

TypeError – if read value of type not compatible with return_num_type

write_name(name: str, value: Real) → None

Write one value to a named output.

Parameters:

• name – String or with name of LabJack IO

• value – is the value to write to the named IO port

write_names(name_value_dict: dict[str, Real]) → None

Write more than one value at once to named outputs.

Parameters:

name_value_dict – is a dictionary with string names of LabJack IO as keys and corresponding numeric values

class LJMCommunicationConfig(device_type: str | DeviceType = 'ANY', connection_type: str | ConnectionType = 'ANY', identifier: str = 'ANY')

Bases: object

Configuration dataclass for LJMCommunication.

class ConnectionType(value=<no_arg>, names=None, module=None, qualname=None, type=None, start=1, boundary=None)

Bases: AutoNumberNameEnum

LabJack connection type.

ANY = 1

ETHERNET = 4

TCP = 3

USB = 2

WIFI = 5

class DeviceType(value=<no_arg>, names=None, module=None, qualname=None, type=None, start=1, boundary=None)

Bases: AutoNumberNameEnum

LabJack device types.

Can be also looked up by ambigious Product ID (p_id) or by instance name: `python LabJackDeviceType(4) is LabJackDeviceType('T4') `

ANY = 1

T4 = 2

T7 = 3

T7_PRO = 4

classmethod get_by_p_id(p_id: int) → DeviceType | list[DeviceType]

Get LabJack device type instance via LabJack product ID.

Note: Product ID is not unambiguous for LabJack devices.

Parameters:

p_id – Product ID of a LabJack device

Returns:

Instance or list of instances of LabJackDeviceType

Raises:

ValueError – when Product ID is unknown

clean_values() → None

Performs value checks on device_type and connection_type.

connection_type: str | ConnectionType = 'ANY'

Can be either string or of enum ConnectionType.

device_type: str | DeviceType = 'ANY'

Can be either string ‘ANY’, ‘T7_PRO’, ‘T7’, ‘T4’, or of enum DeviceType.

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

identifier: str = 'ANY'

The identifier specifies information for the connection to be used. This can be an IP address, serial number, or device name. See the LabJack docs ( https://labjack.com/support/software/api/ljm/function-reference/ljmopens/identifier-parameter) for more information.

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.

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 LJMCommunicationError

Bases: CommunicationError

Errors coming from LJMCommunication.