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#
# This file is part of the PyMeasure package.
#
# Copyright (c) 2013-2024 PyMeasure Developers
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#
import logging
from warnings import warn
import pyvisa
import numpy as np
from .adapter import Adapter
from .protocol import ProtocolAdapter
log = logging.getLogger(__name__)
log.addHandler(logging.NullHandler())
# noinspection PyPep8Naming,PyUnresolvedReferences
class VISAAdapter(Adapter):
""" Adapter class for the VISA library, using PyVISA to communicate with instruments.
The workhorse of our library, used by most instruments.
:param resource_name: A
`VISA resource string <https://pyvisa.readthedocs.io/en/latest/introduction/names.html>`__
or GPIB address integer that identifies the target of the connection
:param visa_library: PyVISA VisaLibrary Instance, path of the VISA library or VisaLibrary spec
string (``@py`` or ``@ivi``). If not given, the default for the platform will be used.
:param preprocess_reply: An optional callable used to preprocess strings
received from the instrument. The callable returns the processed string.
.. deprecated:: 0.11
Implement it in the instrument's `read` method instead.
:param float query_delay: Time in s to wait after writing and before reading.
.. deprecated:: 0.11
Implement it in the instrument's `wait_for` method instead.
:param log: Parent logger of the 'Adapter' logger.
:param \\**kwargs: Keyword arguments for configuring the PyVISA connection.
:Kwargs:
Keyword arguments are used to configure the connection created by PyVISA. This is
complicated by the fact that *which* arguments are valid depends on the interface (e.g.
serial, GPIB, TCPI/IP, USB) determined by the current ``resource_name``.
A flexible process is used to easily define reasonable *default values* for
different instrument interfaces, but also enable the instrument user to *override any
setting* if their situation demands it.
A kwarg that names a pyVISA interface type (most commonly ``asrl``, ``gpib``, ``tcpip``, or
``usb``) is a dictionary with keyword arguments defining defaults specific to that
interface. Example: ``asrl={'baud_rate': 4200}``.
All other kwargs are either generally valid (e.g. ``timeout=500``) or override any default
settings from the interface-specific entries above. For example, passing
``baud_rate=115200`` when connecting via a resource name ``ASRL1`` would override a
default of 4200 defined as above.
See :ref:`connection_settings` for how to tweak settings when *connecting* to an instrument.
See :ref:`default_connection_settings` for how to best define default settings when
*implementing an instrument*.
"""
def __init__(self, resource_name, visa_library='', preprocess_reply=None,
query_delay=0, log=None, **kwargs):
super().__init__(preprocess_reply=preprocess_reply, log=log)
if query_delay:
warn(("Parameter `query_delay` is deprecated. "
"Implement in Instrument's `wait_for` instead."),
FutureWarning)
kwargs.setdefault("query_delay", query_delay)
self.query_delay = query_delay
if isinstance(resource_name, ProtocolAdapter):
self.connection = resource_name
self.connection.write_raw = self.connection.write_bytes
self.read_bytes = self.connection.read_bytes
return
elif isinstance(resource_name, VISAAdapter):
# Allow to reuse the connection.
self.resource_name = getattr(resource_name, "resource_name", None)
self.connection = resource_name.connection
self.manager = resource_name.manager
self.query_delay = resource_name.query_delay
return
elif isinstance(resource_name, int):
resource_name = "GPIB0::%d::INSTR" % resource_name
self.resource_name = resource_name
self.manager = pyvisa.ResourceManager(visa_library)
# Clean up kwargs considering the interface type matching resource_name
if_type = self.manager.resource_info(self.resource_name).interface_type
for key in list(kwargs.keys()): # iterate over a copy of the keys as we modify kwargs
# Remove all interface-specific kwargs:
if key in pyvisa.constants.InterfaceType.__members__:
if getattr(pyvisa.constants.InterfaceType, key) is if_type:
# For the present interface, dump contents into kwargs first if they are not
# present already. This way, it is possible to override default values with
# kwargs passed to Instrument.__init__()
for k, v in kwargs[key].items():
kwargs.setdefault(k, v)
del kwargs[key]
self.connection = self.manager.open_resource(
resource_name,
**kwargs
)
def close(self):
"""Close the connection.
.. note::
This closes the connection to the resource for all adapters using
it currently (e.g. different adapters using the same GPIB line).
"""
super().close()
try:
if self.manager.visalib.library_path == "unset":
# if using the pyvisa-sim library the manager has to be also closed.
# this works around https://github.com/pyvisa/pyvisa-sim/issues/82
self.manager.close()
except AttributeError:
# AttributeError can occur during __del__ calling close
pass
def _write(self, command, **kwargs):
"""Write a string command to the instrument appending `write_termination`.
:param str command: Command string to be sent to the instrument
(without termination).
:param \\**kwargs: Keyword arguments for the connection itself.
"""
self.connection.write(command, **kwargs)
def _write_bytes(self, content, **kwargs):
"""Write the bytes `content` to the instrument.
:param bytes content: The bytes to write to the instrument.
:param \\**kwargs: Keyword arguments for the connection itself.
"""
self.connection.write_raw(content, **kwargs)
def _read(self, **kwargs):
"""Read up to (excluding) `read_termination` or the whole read buffer.
:param \\**kwargs: Keyword arguments for the connection itself.
:returns str: ASCII response of the instrument (excluding read_termination).
"""
return self.connection.read(**kwargs)
def _read_bytes(self, count, break_on_termchar=False, **kwargs):
"""Read a certain number of bytes from the instrument.
:param int count: Number of bytes to read. A value of -1 indicates to
read from the whole read buffer until timeout.
:param bool break_on_termchar: Stop reading at a termination character.
:param \\**kwargs: Keyword arguments for the connection itself.
:returns bytes: Bytes response of the instrument (including termination).
"""
if count >= 0:
return self.connection.read_bytes(count, break_on_termchar=break_on_termchar, **kwargs)
elif break_on_termchar:
return self.connection.read_raw(None, **kwargs)
else:
# pyvisa's `read_raw` reads until newline, if no termination_character defined
# and if not configured to stop at a termination lane etc.
# see https://github.com/pyvisa/pyvisa/issues/728
result = bytearray()
while True:
try:
result.extend(self.connection.read_bytes(1))
except pyvisa.errors.VisaIOError as exc:
if exc.error_code == pyvisa.constants.StatusCode.error_timeout:
return bytes(result)
raise
def ask(self, command):
""" Writes the command to the instrument and returns the resulting
ASCII response
.. deprecated:: 0.11
Call `Instrument.ask` instead.
:param command: SCPI command string to be sent to the instrument
:returns: String ASCII response of the instrument
"""
warn("`Adapter.ask` is deprecated, call `Instrument.ask` instead.", FutureWarning)
return self.connection.query(command)
def ask_values(self, command, **kwargs):
""" Writes a command to the instrument and returns a list of formatted
values from the result. This leverages the `query_ascii_values` method
in PyVISA.
.. deprecated:: 0.11
Call `Instrument.values` instead.
:param command: SCPI command to be sent to the instrument
:param \\**kwargs: Key-word arguments to pass onto `query_ascii_values`
:returns: Formatted response of the instrument.
"""
warn("`Adapter.ask_values` is deprecated, call `Instrument.values` instead.",
FutureWarning)
return self.connection.query_ascii_values(command, **kwargs)
def binary_values(self, command, header_bytes=0, dtype=np.float32):
""" Returns a numpy array from a query for binary data
.. deprecated:: 0.11
Call `Instrument.binary_values` instead.
:param command: SCPI command to be sent to the instrument
:param header_bytes: Integer number of bytes to ignore in header
:param dtype: The NumPy data type to format the values with
:returns: NumPy array of values
"""
warn("`Adapter.binary_values` is deprecated, call `Instrument.binary_values` instead.",
FutureWarning)
self.connection.write(command)
binary = self.connection.read_raw()
# header = binary[:header_bytes]
data = binary[header_bytes:]
return np.fromstring(data, dtype=dtype)
def wait_for_srq(self, timeout=25, delay=0.1):
""" Block until a SRQ, and leave the bit high
:param timeout: Timeout duration in seconds
:param delay: Time delay between checking SRQ in seconds
"""
self.connection.wait_for_srq(timeout * 1000)
def flush_read_buffer(self):
""" Flush and discard the input buffer
As detailed by pyvisa, discard the read and receivee buffer contents
and if data was present in the read buffer and no END-indicator was present,
read from the device until encountering an END indicator (which causes loss of data).
"""
try:
self.connection.flush(pyvisa.constants.BufferOperation.discard_read_buffer)
self.connection.flush(pyvisa.constants.BufferOperation.discard_receive_buffer)
except NotImplementedError:
# NotImplementedError is raised when using resource types other than `asrl`
# in conjunction with pyvisa-py.
# Upstream issue: https://github.com/pyvisa/pyvisa-py/issues/348
# fake discarding the read buffer by reading all available messages.
timeout = self.connection.timeout
self.connection.timeout = 0
try:
self.read_bytes(-1)
except pyvisa.errors.VisaIOError:
pass
finally:
self.connection.timeout = timeout
def __repr__(self):
return "<VISAAdapter(resource='%s')>" % self.connection.resource_name
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