pylablib.devices.Voltcraft package

Submodules

pylablib.devices.Voltcraft.base module

exception pylablib.devices.Voltcraft.base.GenericVoltcraftError

Bases: DeviceError

Generic Voltcraft error

add_note()

Exception.add_note(note) – add a note to the exception

args

with_traceback()

Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception pylablib.devices.Voltcraft.base.GenericVoltcraftBackendError(exc)

Bases: GenericVoltcraftError, DeviceBackendError

Voltcraft backend communication error

add_note()

Exception.add_note(note) – add a note to the exception

args

with_traceback()

Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

pylablib.devices.Voltcraft.multimeter module

class pylablib.devices.Voltcraft.multimeter.VC7055(addr)

Bases: SCPIDevice

Voltcraft VC-7055BT bench-top multimeter.

Parameters:

addr – device connection (usually a COM-port name such as "COM1").

Error

alias of GenericVoltcraftError

ReraiseError

alias of GenericVoltcraftBackendError

get_function(channel='primary')

Get measurement function for the given measurement channel ("primary" or "secondary", or "all" for both channels)

set_function(function, channel='primary', reset_secondary=True)

Set measurement function for the given measurement channel ("primary", "secondary", or "all" for both channels).

If reset_secondary==True and the primary function is changed, set the secondary function to "none" to avoid conflicts.

get_range()

Get the present measurement range

set_range(rng)

Set the present measurement range

is_autorange_enabled()

Check if autoscaling is enabled

enable_autorange(enable=True)

Enable or disable autoscaling

get_measurement_rate()

Get measurement update rate ("fast"", "med", or "slow")

set_measurement_rate(rate)

Set measurement update rate ("fast"", "med", or "slow")

get_reading(channel='primary')

Return the latest reading of the given measurement channel ("primary", "secondary", or "all" for both channels)

BackendError

alias of DeviceBackendError

apply_settings(settings)

Apply the settings.

settings is a dict {name: value} of the available device settings. Non-applicable settings are ignored.

ask(msg, data_type='string', delay=0.0, timeout=None, read_echo=False)

Write a message and read a reply.

msg is the query message, delay is the delay between write and read. Other parameters are the same as in read(). If read_echo==True, assume that the device first echoes the input and skip it.

close()

Close the backend

flush(one_line=False)

Flush the read buffer (read all the available data and return the number of bytes read).

If one_line==True, read only a single line.

static get_arg_type(arg)

Autodetect argument type

get_device_variable(key)

Get the value of a settings, status, or full info parameter

get_esr(timeout=None)

Get the device status register (by default, "*ESR?" command)

get_full_info(include=0)

Get dict {name: value} containing full device information (including status and settings).

include specifies either a list of variables (only these variables are returned), a priority threshold (only values with the priority equal or higher are returned), or "all" (all available variables). Since the lowest priority is -10, setting include=-10 queries all available variables, which is equivalent to include="all".

get_full_status(include=0)

Get dict {name: value} containing the device status (including settings).

include specifies either a list of variables (only these variables are returned), a priority threshold (only values with the priority equal or higher are returned), or "all" (all available variables). Since the lowest priority is -10, setting include=-10 queries all available variables, which is equivalent to include="all".

get_id(timeout=None)

Get the device IDN. (query SCPI '*IDN?' command)

get_settings(include=0)

Get dict {name: value} containing all the device settings.

include specifies either a list of variables (only these variables are returned), a priority threshold (only values with the priority equal or higher are returned), or "all" (all available variables). Since the lowest priority is -10, setting include=-10 queries all available variables, which is equivalent to include="all".

is_opened()

Check if the device is connected

lock(timeout=None)

Lock the access to the device from other threads/processes (isn’t necessarily implemented)

locking(timeout=None)

Context manager for lock & unlock

open()

Open the backend

static parse_array_data(data, fmt, include_header=False)

Parse the data returned by the device. fmt is DataFormat description in numpy format (e.g., "<u2").

If include_header==True, the data is assumed to be in a (somewhat) standard SCPI format: b'#', then a single digit s denoting length of the size block, then s digits denoting length of the data (in bytes) followed by the actual data. Otherwise (include_header==False), assume that the header is already removed.

read(data_type='string', timeout=None)

Read data from the device.

data_type determines the type of the data. Can be 'raw' (just raw data), 'string' (with trailing and leading spaces stripped), 'int', 'float', 'bool' (interprets 0 or 'off' as False, anything else as True), 'value' (returns tuple (value, unit), where value is float), a callable (return the result of this callable applied to the string value), a dictionary (return the stored value corresponding to the string value, or to the value converted into integer if the string value is not present), or a list of data types (the result is treated as a list of values with the given types separated by commas). timeout overrides the default value.

read_binary_array_data(include_header=False, timeout=None, flush_term=True)

Read a binary data in the from the device.

The data assumes the standard binary transfer header consisting of "#" symbol, then a single digit with the size of the length string, then the length string containing the length of the binary data (in bytes). If include_header==True, return the data with the header; otherwise, return only the content. If flush_term==True, flush the following line to skip terminator characters after the binary data, which are added by some devices. timeout overrides the default value.

reconnect(new_instrument=True, ignore_error=True)

Remake the connection.

If new_instrument==True, create a new backend instance. If ignore_error==True, ignore errors on closing.

reset()

Reset the device (by default, "*RST" command)

set_device_variable(key, value)

Set the value of a settings parameter

sleep(delay)

Wait for delay seconds

unlock()

Unlock the access to the device from other threads/processes (isn’t necessarily implemented)

using_write_buffer()

Context manager for using a write buffer.

While it’s active, all the consecutive write() operations are bundled together with ; delimiter. The actual write is performed at the read()/ask() operation or at the end of the block.

wait(wait_type='sync', timeout=None, wait_callback=None)

Pause execution until device overlapped commands are complete.

wait_type is either 'sync' (perform wait_sync()), 'dev' (perform wait_dev()) or 'none' (do nothing).

wait_dev()

Pause execution of the device commands until device overlapped commands (e.g., taking sweeps) are complete.

Note that the code execution is not paused.

wait_sync(timeout=None, wait_callback=None)

Pause execution of the script until device overlapped commands (e.g., taking sweeps) are complete.

timeout and wait_callback override default constructor parameters.

write(msg, arg=None, arg_type=None, unit=None, bool_selector=None, wait_sync=None, read_echo=False, read_echo_delay=0.0)

Send a command.

Parameters:

• msg (str) – Text message.

• arg – Optional argument to append in the end. If a list of arguments is supplied, the result is joined with ",".

• arg_type (str) – Argument type. Can be 'raw' (in which case data is sent raw), 'string', 'int', 'float', 'bool', a format string (such as '{:.3f}') or a list of argument types (for an iterable argument); if format string is used and the argument is a list or a tuple, then it is expanded as a list of arguments (e.g., arg_type='{0};{1}' with arg=[1,2] will produce a string '1;2'); if a list of types is used, each element of arg is converted using the corresponding type, and the result is joined with ",".

• unit (str) – If not None, use it as a unit to append after the value.

• bool_selector (tuple) – A tuple (false_value, true_value) of two strings to represent bool argument; by default, use ._bool_selector attribute.

• wait_sync – if True, append the sync command (specified as ._wait_sync_comm attribute, "*OPC?" by default) after the message and pause the execution command is complete; useful in long set operations, where the device might ignore later inputs until the current command is complete; if None, use the class default ._default_write_sync attribute (False by default).

• read_echo (bool) – If True, read a single line after write.

• read_echo_delay (float) – The delay between write and read if read_echo==True.

exception pylablib.devices.Voltcraft.multimeter.VC880ParseError

Bases: GenericVoltcraftError

Voltcraft VC880 message parse error

add_note()

Exception.add_note(note) – add a note to the exception

args

with_traceback()

Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

class pylablib.devices.Voltcraft.multimeter.TVC880Reading(func, kind, value, unit, disps, d2func)

Bases: tuple

d2func

disps

func

kind

unit

value

class pylablib.devices.Voltcraft.multimeter.VC880(conn=0)

Bases: ICommBackendWrapper

Voltcraft VC880/VC650BT series multimeter.

Parameters:

conn – device connection (usually, either a HID path, or an integer 0-based index indicating the devices among the ones connected)

Error

alias of GenericVoltcraftError

class TMessage(typ, payload)

Bases: tuple

payload

typ

read_message(tries=10)

Read the oldest message in the queue

exhaust_messages(nmax=100000, tries=10)

Read all messages in the queue and return them

nmax specifies the maximal number of messages to read (None means reading until available).

send_message(comm, data=b'', pre_exhaust=True, reps=1, post_read=0)

Send a message containing the given command and data.

If pre_exhaust==True, empty the read queue before sending the message (improves chances of delivery). reps specifies the number of exhaust/send cycle repetitions (improves chances of delivery). If post_read is more than 0, it specifies the number of messages to read after the command is sent.

get_reading(kind='latest')

Get the multimeter reading.

kind can be "latest" (return the most recent reading), "oldest" (return the oldest reading), or "all" (return all readings in the read queue). Return tuple (func, kind, val, unit, disps, d2func) with, correspondingly, specific selected function (e.g., "DCuA" or "res"), function kind (e.g., "curr_dc" or "res"), displayed value (in SI units), value units (e.g., "V" or "Ohm"), values of the other 3 auxiliary displays (upper right min/max/avg/rel display, upper left memory display, bottom linear scale display), and the kind of function on the upper right display ("min", "max", "avg", or "rel").

enable_autorange(enable=True)

Enable or disable autorange

apply_settings(settings)

Apply the settings.

settings is the dict {name: value} of the device available settings. Non-applicable settings are ignored.

close()

Close the backend

get_device_variable(key)

Get the value of a settings, status, or full info parameter

get_full_info(include=0)

Get dict {name: value} containing full device information (including status and settings).

include specifies either a list of variables (only these variables are returned), a priority threshold (only values with the priority equal or higher are returned), or "all" (all available variables). Since the lowest priority is -10, setting include=-10 queries all available variables, which is equivalent to include="all".

get_full_status(include=0)

Get dict {name: value} containing the device status (including settings).

include specifies either a list of variables (only these variables are returned), a priority threshold (only values with the priority equal or higher are returned), or "all" (all available variables). Since the lowest priority is -10, setting include=-10 queries all available variables, which is equivalent to include="all".

get_settings(include=0)

Get dict {name: value} containing all the device settings.

include specifies either a list of variables (only these variables are returned), a priority threshold (only values with the priority equal or higher are returned), or "all" (all available variables). Since the lowest priority is -10, setting include=-10 queries all available variables, which is equivalent to include="all".

is_opened()

Check if the device is connected

lock(timeout=None)

Lock the access to the device from other threads/processes (isn’t necessarily implemented)

locking(timeout=None)

Context manager for lock & unlock

open()

Open the backend

set_device_variable(key, value)

Set the value of a settings parameter

unlock()

Unlock the access to the device from other threads/processes (isn’t necessarily implemented)

Module contents