pymeasure.adapters
The adapter classes allow the instruments to be independent of the communication method used.
The instrument implementation takes care of any potential quirks in its communication protocol (see Advanced communication protocols), and the adapter takes care of the details of the over-the-wire communication with the hardware device.
In the vast majority of cases, it will be sufficient to pass a connection string or integer to the instrument (see Connecting to an instrument), which uses the pymeasure.adapters.VISAAdapter in the background.
Adapter base class
- class pymeasure.adapters.Adapter(preprocess_reply=None, log=None, **kwargs)
Base class for Adapter child classes, which adapt between the Instrument object and the connection, to allow flexible use of different connection techniques.
This class should only be inherited from.
- Parameters
preprocess_reply –
An optional callable used to preprocess strings received from the instrument. The callable returns the processed string.
Deprecated since version 0.11: Implement it in the instrument’s read method instead.
log – Parent logger of the ‘Adapter’ logger.
**kwargs – Keyword arguments just to be cooperative.
- ask(command)
Write the command to the instrument and returns the resulting ASCII response.
Deprecated since version 0.11: Call Instrument.ask instead.
- Parameters
command – SCPI command string to be sent to the instrument
- Returns
String ASCII response of the instrument
- binary_values(command, header_bytes=0, dtype=<class 'numpy.float32'>)
Returns a numpy array from a query for binary data
Deprecated since version 0.11: Call Instrument.binary_values instead.
- Parameters
command – SCPI command to be sent to the instrument
header_bytes – Integer number of bytes to ignore in header
dtype – The NumPy data type to format the values with
- Returns
NumPy array of values
- close()
Close the connection.
- flush_read_buffer()
Flush and discard the input buffer. Implement in subclass.
- read(**kwargs)
Read up to (excluding) read_termination or the whole read buffer.
Do not override in a subclass!
- Parameters
**kwargs – Keyword arguments for the connection itself.
- Returns str
ASCII response of the instrument (excluding read_termination).
- read_binary_values(header_bytes=0, termination_bytes=None, dtype=<class 'numpy.float32'>, **kwargs)
Returns a numpy array from a query for binary data
- Parameters
header_bytes (int) – Number of bytes to ignore in header.
termination_bytes (int) – Number of bytes to strip at end of message or None.
dtype – The NumPy data type to format the values with.
**kwargs – Further arguments for the NumPy fromstring method.
- Returns
NumPy array of values
- read_bytes(count=-1, break_on_termchar=False, **kwargs)
Read a certain number of bytes from the instrument.
Do not override in a subclass!
- Parameters
count (int) – Number of bytes to read. A value of -1 indicates to read from the whole read buffer.
break_on_termchar (bool) – Stop reading at a termination character.
**kwargs – Keyword arguments for the connection itself.
- Returns bytes
Bytes response of the instrument (including termination).
- values(command, separator=', ', cast=<class 'float'>, preprocess_reply=None)
Write a command to the instrument and returns a list of formatted values from the result.
Deprecated since version 0.11: Call Instrument.values instead.
- Parameters
command – SCPI command to be sent to the instrument
separator – A separator character to split the string into a list
cast – A type to cast the result
preprocess_reply – optional callable used to preprocess values received from the instrument. The callable returns the processed string. If not specified, the Adapter default is used if available, otherwise no preprocessing is done.
- Returns
A list of the desired type, or strings where the casting fails
- write(command, **kwargs)
Write a string command to the instrument appending write_termination.
Do not override in a subclass!
- Parameters
command (str) – Command string to be sent to the instrument (without termination).
**kwargs – Keyword arguments for the connection itself.
- write_binary_values(command, values, termination='', **kwargs)
Write binary data to the instrument, e.g. waveform for signal generators
- Parameters
command – command string to be sent to the instrument
values – iterable representing the binary values
termination – String added afterwards to terminate the message.
**kwargs – Key-word arguments to pass onto
Adapter._format_binary_values()
- Returns
number of bytes written
- write_bytes(content, **kwargs)
Write the bytes content to the instrument.
Do not override in a subclass!
- Parameters
content (bytes) – The bytes to write to the instrument.
**kwargs – Keyword arguments for the connection itself.
VISA adapter
- class pymeasure.adapters.VISAAdapter(resource_name, visa_library='', preprocess_reply=None, query_delay=0, log=None, **kwargs)
Bases:
AdapterAdapter class for the VISA library, using PyVISA to communicate with instruments.
The workhorse of our library, used by most instruments.
- Parameters
resource_name – A VISA resource string or GPIB address integer that identifies the target of the connection
visa_library – PyVISA VisaLibrary Instance, path of the VISA library or VisaLibrary spec string (
@pyor@ivi). If not given, the default for the platform will be used.preprocess_reply –
An optional callable used to preprocess strings received from the instrument. The callable returns the processed string.
Deprecated since version 0.11: Implement it in the instrument’s read method instead.
query_delay (float) –
Time in s to wait after writing and before reading.
Deprecated since version 0.11: Implement it in the instrument’s wait_for method instead.
log – Parent logger of the ‘Adapter’ logger.
**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, orusb) 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, passingbaud_rate=115200when connecting via a resource nameASRL1would override a default of 4200 defined as above.See Modifying connection settings for how to tweak settings when connecting to an instrument. See Defining default connection settings for how to best define default settings when implementing an instrument.
- ask(command)
Writes the command to the instrument and returns the resulting ASCII response
Deprecated since version 0.11: Call Instrument.ask instead.
- Parameters
command – SCPI command string to be sent to the instrument
- Returns
String ASCII response of the instrument
- ask_values(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 since version 0.11: Call Instrument.values instead.
- Parameters
command – SCPI command to be sent to the instrument
**kwargs – Key-word arguments to pass onto query_ascii_values
- Returns
Formatted response of the instrument.
- binary_values(command, header_bytes=0, dtype=<class 'numpy.float32'>)
Returns a numpy array from a query for binary data
Deprecated since version 0.11: Call Instrument.binary_values instead.
- Parameters
command – SCPI command to be sent to the instrument
header_bytes – Integer number of bytes to ignore in header
dtype – The NumPy data type to format the values with
- Returns
NumPy array of values
- close()
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).
- flush_read_buffer()
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).
- read(**kwargs)
Read up to (excluding) read_termination or the whole read buffer.
Do not override in a subclass!
- Parameters
**kwargs – Keyword arguments for the connection itself.
- Returns str
ASCII response of the instrument (excluding read_termination).
- read_binary_values(header_bytes=0, termination_bytes=None, dtype=<class 'numpy.float32'>, **kwargs)
Returns a numpy array from a query for binary data
- Parameters
header_bytes (int) – Number of bytes to ignore in header.
termination_bytes (int) – Number of bytes to strip at end of message or None.
dtype – The NumPy data type to format the values with.
**kwargs – Further arguments for the NumPy fromstring method.
- Returns
NumPy array of values
- read_bytes(count=-1, break_on_termchar=False, **kwargs)
Read a certain number of bytes from the instrument.
Do not override in a subclass!
- Parameters
count (int) – Number of bytes to read. A value of -1 indicates to read from the whole read buffer.
break_on_termchar (bool) – Stop reading at a termination character.
**kwargs – Keyword arguments for the connection itself.
- Returns bytes
Bytes response of the instrument (including termination).
- values(command, separator=', ', cast=<class 'float'>, preprocess_reply=None)
Write a command to the instrument and returns a list of formatted values from the result.
Deprecated since version 0.11: Call Instrument.values instead.
- Parameters
command – SCPI command to be sent to the instrument
separator – A separator character to split the string into a list
cast – A type to cast the result
preprocess_reply – optional callable used to preprocess values received from the instrument. The callable returns the processed string. If not specified, the Adapter default is used if available, otherwise no preprocessing is done.
- Returns
A list of the desired type, or strings where the casting fails
- wait_for_srq(timeout=25, delay=0.1)
Block until a SRQ, and leave the bit high
- Parameters
timeout – Timeout duration in seconds
delay – Time delay between checking SRQ in seconds
- write(command, **kwargs)
Write a string command to the instrument appending write_termination.
Do not override in a subclass!
- Parameters
command (str) – Command string to be sent to the instrument (without termination).
**kwargs – Keyword arguments for the connection itself.
- write_binary_values(command, values, termination='', **kwargs)
Write binary data to the instrument, e.g. waveform for signal generators
- Parameters
command – command string to be sent to the instrument
values – iterable representing the binary values
termination – String added afterwards to terminate the message.
**kwargs – Key-word arguments to pass onto
Adapter._format_binary_values()
- Returns
number of bytes written
- write_bytes(content, **kwargs)
Write the bytes content to the instrument.
Do not override in a subclass!
- Parameters
content (bytes) – The bytes to write to the instrument.
**kwargs – Keyword arguments for the connection itself.
Serial adapter
- class pymeasure.adapters.SerialAdapter(port, preprocess_reply=None, write_termination='', read_termination='', **kwargs)
Bases:
AdapterAdapter class for using the Python Serial package to allow serial communication to instrument
- Parameters
port – Serial port
preprocess_reply –
An optional callable used to preprocess strings received from the instrument. The callable returns the processed string.
Deprecated since version 0.11: Implement it in the instrument’s read method instead.
write_termination – String appended to messages before writing them.
read_termination – String expected at end of read message and removed.
**kwargs – Any valid key-word argument for serial.Serial
- _format_binary_values(values, datatype='f', is_big_endian=False, header_fmt='ieee')
Format values in binary format, used internally in
Adapter.write_binary_values().- Parameters
values – data to be written to the device.
datatype – the format string for a single element. See struct module.
is_big_endian – boolean indicating endianess.
header_fmt – Format of the header prefixing the data (“ieee”, “hp”, “empty”).
- Returns
binary string.
- Return type
bytes
- ask(command)
Write the command to the instrument and returns the resulting ASCII response.
Deprecated since version 0.11: Call Instrument.ask instead.
- Parameters
command – SCPI command string to be sent to the instrument
- Returns
String ASCII response of the instrument
- binary_values(command, header_bytes=0, dtype=<class 'numpy.float32'>)
Returns a numpy array from a query for binary data
Deprecated since version 0.11: Call Instrument.binary_values instead.
- Parameters
command – SCPI command to be sent to the instrument
header_bytes – Integer number of bytes to ignore in header
dtype – The NumPy data type to format the values with
- Returns
NumPy array of values
- close()
Close the connection.
- flush_read_buffer()
Flush and discard the input buffer.
- read(**kwargs)
Read up to (excluding) read_termination or the whole read buffer.
Do not override in a subclass!
- Parameters
**kwargs – Keyword arguments for the connection itself.
- Returns str
ASCII response of the instrument (excluding read_termination).
- read_binary_values(header_bytes=0, termination_bytes=None, dtype=<class 'numpy.float32'>, **kwargs)
Returns a numpy array from a query for binary data
- Parameters
header_bytes (int) – Number of bytes to ignore in header.
termination_bytes (int) – Number of bytes to strip at end of message or None.
dtype – The NumPy data type to format the values with.
**kwargs – Further arguments for the NumPy fromstring method.
- Returns
NumPy array of values
- read_bytes(count=-1, break_on_termchar=False, **kwargs)
Read a certain number of bytes from the instrument.
Do not override in a subclass!
- Parameters
count (int) – Number of bytes to read. A value of -1 indicates to read from the whole read buffer.
break_on_termchar (bool) – Stop reading at a termination character.
**kwargs – Keyword arguments for the connection itself.
- Returns bytes
Bytes response of the instrument (including termination).
- values(command, separator=', ', cast=<class 'float'>, preprocess_reply=None)
Write a command to the instrument and returns a list of formatted values from the result.
Deprecated since version 0.11: Call Instrument.values instead.
- Parameters
command – SCPI command to be sent to the instrument
separator – A separator character to split the string into a list
cast – A type to cast the result
preprocess_reply – optional callable used to preprocess values received from the instrument. The callable returns the processed string. If not specified, the Adapter default is used if available, otherwise no preprocessing is done.
- Returns
A list of the desired type, or strings where the casting fails
- write(command, **kwargs)
Write a string command to the instrument appending write_termination.
Do not override in a subclass!
- Parameters
command (str) – Command string to be sent to the instrument (without termination).
**kwargs – Keyword arguments for the connection itself.
- write_binary_values(command, values, termination='', **kwargs)
Write binary data to the instrument, e.g. waveform for signal generators
- Parameters
command – command string to be sent to the instrument
values – iterable representing the binary values
termination – String added afterwards to terminate the message.
**kwargs – Key-word arguments to pass onto
Adapter._format_binary_values()
- Returns
number of bytes written
- write_bytes(content, **kwargs)
Write the bytes content to the instrument.
Do not override in a subclass!
- Parameters
content (bytes) – The bytes to write to the instrument.
**kwargs – Keyword arguments for the connection itself.
Prologix adapter
- class pymeasure.adapters.PrologixAdapter(resource_name, address=None, rw_delay=0, serial_timeout=None, preprocess_reply=None, auto=False, eoi=True, eos='\n', gpib_read_timeout=None, **kwargs)
Bases:
VISAAdapterEncapsulates the additional commands necessary to communicate over a Prologix GPIB-USB Adapter, using the
VISAAdapter.Each PrologixAdapter is constructed based on a connection to the Prologix device itself and the GPIB address of the instrument to be communicated to. Connection sharing is achieved by using the
gpib()method to spawn new PrologixAdapters for different GPIB addresses.- Parameters
resource_name – A VISA resource string that identifies the connection to the Prologix device itself, for example “ASRL5” for the 5th COM port.
address – Integer GPIB address of the desired instrument.
rw_delay –
An optional delay to set between a write and read call for slow to respond instruments.
Deprecated since version 0.11: Implement it in the instrument’s wait_for method instead.
preprocess_reply –
optional callable used to preprocess strings received from the instrument. The callable returns the processed string.
Deprecated since version 0.11: Implement it in the instrument’s read method instead.
auto – Enable or disable read-after-write and address instrument to listen.
eoi – Enable or disable EOI assertion.
eos – Set command termination string (CR+LF, CR, LF, or “”)
gpib_read_timeout – Set read timeout for GPIB communication in milliseconds from 1..3000
kwargs – Key-word arguments if constructing a new serial object
- Variables
address – Integer GPIB address of the desired instrument.
Usage example:
adapter = PrologixAdapter("ASRL5::INSTR", 7) sourcemeter = Keithley2400(adapter) # at GPIB address 7 # generate another instance with a different GPIB address: adapter2 = adapter.gpib(9) multimeter = Keithley2000(adapter2) # at GPIB address 9
To allow user access to the Prologix adapter in Linux, create the file:
/etc/udev/rules.d/51-prologix.rules, with contents:SUBSYSTEMS=="usb",ATTRS{idVendor}=="0403",ATTRS{idProduct}=="6001",MODE="0666"
Then reload the udev rules with:
sudo udevadm control --reload-rules sudo udevadm trigger
- _format_binary_values(values, datatype='f', is_big_endian=False, header_fmt='ieee')
Format values in binary format, used internally in
write_binary_values().- Parameters
values – data to be written to the device.
datatype – the format string for a single element. See struct module.
is_big_endian – boolean indicating endianess.
header_fmt – Format of the header prefixing the data (“ieee”, “hp”, “empty”).
- Returns
binary string.
- Return type
bytes
- ask(command)
Ask the Prologix controller.
Deprecated since version 0.11: Call Instrument.ask instead.
- Parameters
command – SCPI command string to be sent to instrument
- ask_values(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 since version 0.11: Call Instrument.values instead.
- Parameters
command – SCPI command to be sent to the instrument
**kwargs – Key-word arguments to pass onto query_ascii_values
- Returns
Formatted response of the instrument.
- property auto
Control whether to address instruments to talk after sending them a command (bool).
Configure Prologix GPIB controller to automatically address instruments to talk after sending them a command in order to read their response. The feature called, Read-After-Write, saves the user from having to issue read commands repeatedly. This property enables (True) or disables (False) this feature.
- binary_values(command, header_bytes=0, dtype=<class 'numpy.float32'>)
Returns a numpy array from a query for binary data
Deprecated since version 0.11: Call Instrument.binary_values instead.
- Parameters
command – SCPI command to be sent to the instrument
header_bytes – Integer number of bytes to ignore in header
dtype – The NumPy data type to format the values with
- Returns
NumPy array of values
- close()
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).
- property eoi
Control whether to assert the EOI signal with the last character of any command sent over GPIB port (bool).
Some instruments require EOI signal to be asserted in order to properly detect the end of a command.
- property eos
Control GPIB termination characters (str).
- possible values:
CR+LF
CR
LF
empty string
When data from host is received, all non-escaped LF, CR and ESC characters are removed and GPIB terminators, as specified by this command, are appended before sending the data to instruments. This command does not affect data from instruments received over GPIB port.
- flush_read_buffer()
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).
- gpib(address, **kwargs)
Return a PrologixAdapter object that references the GPIB address specified, while sharing the Serial connection with other calls of this function
- Parameters
address – Integer GPIB address of the desired instrument
kwargs – Arguments for the initialization
- Returns
PrologixAdapter for specific GPIB address
- property gpib_read_timeout
Control the timeout value for the GPIB communication in milliseconds
possible values: 1 - 3000
- read(**kwargs)
Read up to (excluding) read_termination or the whole read buffer.
Do not override in a subclass!
- Parameters
**kwargs – Keyword arguments for the connection itself.
- Returns str
ASCII response of the instrument (excluding read_termination).
- read_binary_values(header_bytes=0, termination_bytes=None, dtype=<class 'numpy.float32'>, **kwargs)
Returns a numpy array from a query for binary data
- Parameters
header_bytes (int) – Number of bytes to ignore in header.
termination_bytes (int) – Number of bytes to strip at end of message or None.
dtype – The NumPy data type to format the values with.
**kwargs – Further arguments for the NumPy fromstring method.
- Returns
NumPy array of values
- read_bytes(count=-1, break_on_termchar=False, **kwargs)
Read a certain number of bytes from the instrument.
Do not override in a subclass!
- Parameters
count (int) – Number of bytes to read. A value of -1 indicates to read from the whole read buffer.
break_on_termchar (bool) – Stop reading at a termination character.
**kwargs – Keyword arguments for the connection itself.
- Returns bytes
Bytes response of the instrument (including termination).
- reset()
Perform a power-on reset of the controller.
The process takes about 5 seconds. All input received during this time is ignored and the connection is closed.
- values(command, separator=', ', cast=<class 'float'>, preprocess_reply=None)
Write a command to the instrument and returns a list of formatted values from the result.
Deprecated since version 0.11: Call Instrument.values instead.
- Parameters
command – SCPI command to be sent to the instrument
separator – A separator character to split the string into a list
cast – A type to cast the result
preprocess_reply – optional callable used to preprocess values received from the instrument. The callable returns the processed string. If not specified, the Adapter default is used if available, otherwise no preprocessing is done.
- Returns
A list of the desired type, or strings where the casting fails
- property version
Get the version string of the Prologix controller.
- wait_for_srq(timeout=25, delay=0.1)
Blocks until a SRQ, and leaves the bit high
- Parameters
timeout – Timeout duration in seconds.
delay – Time delay between checking SRQ in seconds.
- Raises
TimeoutError – “Waiting for SRQ timed out.”
- write(command, **kwargs)
Write a string command to the instrument appending write_termination.
If the GPIB address in
addressis defined, it is sent first.- Parameters
command (str) – Command string to be sent to the instrument (without termination).
kwargs – Keyword arguments for the connection itself.
- write_binary_values(command, values, **kwargs)
Write binary data to the instrument, e.g. waveform for signal generators.
values are encoded in a binary format according to IEEE 488.2 Definite Length Arbitrary Block Response Data block.
- Parameters
command – SCPI command to be sent to the instrument
values – iterable representing the binary values
kwargs – Key-word arguments to pass onto
_format_binary_values()
- Returns
number of bytes written
- write_bytes(content, **kwargs)
Write the bytes content to the instrument.
Do not override in a subclass!
- Parameters
content (bytes) – The bytes to write to the instrument.
**kwargs – Keyword arguments for the connection itself.
VXI-11 adapter
- class pymeasure.adapters.VXI11Adapter(host, preprocess_reply=None, **kwargs)
Bases:
Adapter- VXI11 Adapter class. Provides a adapter object that
wraps around the read, write and ask functionality of the vxi11 library.
Deprecated since version 0.11: Use VISAAdapter instead.
- Parameters
host – string containing the visa connection information.
preprocess_reply – (deprecated) optional callable used to preprocess strings received from the instrument. The callable returns the processed string.
- ask(command)
Wrapper function for the ask command using the vx11 interface.
Deprecated since version 0.11: Call Instrument.ask instead.
- Parameters
command – string with the command that will be transmitted to the instrument.
:returns string containing a response from the device.
- ask_raw(command)
Wrapper function for the ask_raw command using the vx11 interface.
Deprecated since version 0.11: Use Instrument.write_bytes and Instrument.read_bytes instead.
- Parameters
command – binary string with the command that will be transmitted to the instrument
:returns binary string containing the response from the device.
- binary_values(command, header_bytes=0, dtype=<class 'numpy.float32'>)
Returns a numpy array from a query for binary data
Deprecated since version 0.11: Call Instrument.binary_values instead.
- Parameters
command – SCPI command to be sent to the instrument
header_bytes – Integer number of bytes to ignore in header
dtype – The NumPy data type to format the values with
- Returns
NumPy array of values
- close()
Close the connection.
- flush_read_buffer()
Flush and discard the input buffer. Implement in subclass.
- read(**kwargs)
Read up to (excluding) read_termination or the whole read buffer.
Do not override in a subclass!
- Parameters
**kwargs – Keyword arguments for the connection itself.
- Returns str
ASCII response of the instrument (excluding read_termination).
- read_binary_values(header_bytes=0, termination_bytes=None, dtype=<class 'numpy.float32'>, **kwargs)
Returns a numpy array from a query for binary data
- Parameters
header_bytes (int) – Number of bytes to ignore in header.
termination_bytes (int) – Number of bytes to strip at end of message or None.
dtype – The NumPy data type to format the values with.
**kwargs – Further arguments for the NumPy fromstring method.
- Returns
NumPy array of values
- read_bytes(count=-1, break_on_termchar=False, **kwargs)
Read a certain number of bytes from the instrument.
Do not override in a subclass!
- Parameters
count (int) – Number of bytes to read. A value of -1 indicates to read from the whole read buffer.
break_on_termchar (bool) – Stop reading at a termination character.
**kwargs – Keyword arguments for the connection itself.
- Returns bytes
Bytes response of the instrument (including termination).
- read_raw()
Read bytes from the device.
Deprecated since version 0.11: Use read_bytes instead.
- values(command, separator=', ', cast=<class 'float'>, preprocess_reply=None)
Write a command to the instrument and returns a list of formatted values from the result.
Deprecated since version 0.11: Call Instrument.values instead.
- Parameters
command – SCPI command to be sent to the instrument
separator – A separator character to split the string into a list
cast – A type to cast the result
preprocess_reply – optional callable used to preprocess values received from the instrument. The callable returns the processed string. If not specified, the Adapter default is used if available, otherwise no preprocessing is done.
- Returns
A list of the desired type, or strings where the casting fails
- write(command, **kwargs)
Write a string command to the instrument appending write_termination.
Do not override in a subclass!
- Parameters
command (str) – Command string to be sent to the instrument (without termination).
**kwargs – Keyword arguments for the connection itself.
- write_binary_values(command, values, termination='', **kwargs)
Write binary data to the instrument, e.g. waveform for signal generators
- Parameters
command – command string to be sent to the instrument
values – iterable representing the binary values
termination – String added afterwards to terminate the message.
**kwargs – Key-word arguments to pass onto
Adapter._format_binary_values()
- Returns
number of bytes written
- write_bytes(content, **kwargs)
Write the bytes content to the instrument.
Do not override in a subclass!
- Parameters
content (bytes) – The bytes to write to the instrument.
**kwargs – Keyword arguments for the connection itself.
- write_raw(command)
Write bytes to the device.
Deprecated since version 0.11: Use write_bytes instead.
Telnet adapter
- class pymeasure.adapters.TelnetAdapter(host, port=0, query_delay=0, preprocess_reply=None, **kwargs)
Bases:
AdapterAdapter class for using the Python telnetlib package to allow communication to instruments
This Adapter has been removed from service as the underlying library is missing!
Deprecated since version 0.11.2: The Python telnetlib module is deprecated since Python 3.11 and will be removed in Python 3.13 release. As a result, TelnetAdapter is deprecated, use VISAAdapter instead. The VISAAdapter supports TCPIP socket connections. When using the VISAAdapter, the resource_name argument should be TCPIP[board]::<host>::<port>::SOCKET. see here, <https://pyvisa.readthedocs.io/en/latest/introduction/names.html>
- ask(command)
Write the command to the instrument and returns the resulting ASCII response.
Deprecated since version 0.11: Call Instrument.ask instead.
- Parameters
command – SCPI command string to be sent to the instrument
- Returns
String ASCII response of the instrument
- binary_values(command, header_bytes=0, dtype=<class 'numpy.float32'>)
Returns a numpy array from a query for binary data
Deprecated since version 0.11: Call Instrument.binary_values instead.
- Parameters
command – SCPI command to be sent to the instrument
header_bytes – Integer number of bytes to ignore in header
dtype – The NumPy data type to format the values with
- Returns
NumPy array of values
- close()
Close the connection.
- flush_read_buffer()
Flush and discard the input buffer. Implement in subclass.
- read(**kwargs)
Read up to (excluding) read_termination or the whole read buffer.
Do not override in a subclass!
- Parameters
**kwargs – Keyword arguments for the connection itself.
- Returns str
ASCII response of the instrument (excluding read_termination).
- read_binary_values(header_bytes=0, termination_bytes=None, dtype=<class 'numpy.float32'>, **kwargs)
Returns a numpy array from a query for binary data
- Parameters
header_bytes (int) – Number of bytes to ignore in header.
termination_bytes (int) – Number of bytes to strip at end of message or None.
dtype – The NumPy data type to format the values with.
**kwargs – Further arguments for the NumPy fromstring method.
- Returns
NumPy array of values
- read_bytes(count=-1, break_on_termchar=False, **kwargs)
Read a certain number of bytes from the instrument.
Do not override in a subclass!
- Parameters
count (int) – Number of bytes to read. A value of -1 indicates to read from the whole read buffer.
break_on_termchar (bool) – Stop reading at a termination character.
**kwargs – Keyword arguments for the connection itself.
- Returns bytes
Bytes response of the instrument (including termination).
- values(command, separator=', ', cast=<class 'float'>, preprocess_reply=None)
Write a command to the instrument and returns a list of formatted values from the result.
Deprecated since version 0.11: Call Instrument.values instead.
- Parameters
command – SCPI command to be sent to the instrument
separator – A separator character to split the string into a list
cast – A type to cast the result
preprocess_reply – optional callable used to preprocess values received from the instrument. The callable returns the processed string. If not specified, the Adapter default is used if available, otherwise no preprocessing is done.
- Returns
A list of the desired type, or strings where the casting fails
- write(command, **kwargs)
Write a string command to the instrument appending write_termination.
Do not override in a subclass!
- Parameters
command (str) – Command string to be sent to the instrument (without termination).
**kwargs – Keyword arguments for the connection itself.
- write_binary_values(command, values, termination='', **kwargs)
Write binary data to the instrument, e.g. waveform for signal generators
- Parameters
command – command string to be sent to the instrument
values – iterable representing the binary values
termination – String added afterwards to terminate the message.
**kwargs – Key-word arguments to pass onto
Adapter._format_binary_values()
- Returns
number of bytes written
- write_bytes(content, **kwargs)
Write the bytes content to the instrument.
Do not override in a subclass!
- Parameters
content (bytes) – The bytes to write to the instrument.
**kwargs – Keyword arguments for the connection itself.
Test adapters
These pieces are useful when writing tests.
- pymeasure.test.expected_protocol(instrument_cls, comm_pairs, connection_attributes=None, connection_methods=None, **kwargs)
Context manager that checks sent/received instrument commands without a device connected.
Given an instrument class and a list of command-response pairs, this context manager confirms that the code in the context manager block produces the expected messages.
Terminators are excluded from the protocol definition, as those are typically a detail of the communication method (i.e. Adapter), and not the protocol itself.
- Parameters
instrument_cls (pymeasure.Instrument) –
Instrumentsubclass to instantiate.comm_pairs (list[2-tuples[str]]) – List of command-response pairs, i.e. 2-tuples like (‘VOLT?’, ‘3.14’). ‘None’ indicates that a pair member (command or response) does not exist, e.g. (None, ‘RESP1’). Commands and responses are without termination characters.
connection_attributes – Dictionary of connection attributes and their values.
connection_methods – Dictionary of method names of the connection and their return values.
**kwargs – Keyword arguments for the instantiation of the instrument.
- class pymeasure.adapters.ProtocolAdapter(comm_pairs=None, preprocess_reply=None, connection_attributes=None, connection_methods=None, **kwargs)
Bases:
AdapterAdapter class for testing the command exchange protocol without instrument hardware.
This adapter is primarily meant for use within
pymeasure.test.expected_protocol().The
connectionattribute is aunittest.mock.MagicMocksuch that every call returns. If you want to set a return value, you can useadapter.connection.some_method.return_value = 7, such that a call toadapter.connection.some_method()will return 7. Similarly, you can verify that this call to the connection method happened withassert adapter.connection.some_method.called is True. You can specify dictionaries with return values of attributes and methods.- Parameters
comm_pairs (list) – List of “reference” message pair tuples. The first element is what is sent to the instrument, the second one is the returned message. ‘None’ indicates that a pair member (write or read) does not exist. The messages do not include the termination characters.
connection_attributes – Dictionary of connection attributes and their values.
connection_methods – Dictionary of method names of the connection and their return values.
- flush_read_buffer()
Flush and discard the input buffer
As detailed by pyvisa, discard the read 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).
- class pymeasure.adapters.FakeAdapter(preprocess_reply=None, log=None, **kwargs)
Bases:
AdapterProvides a fake adapter for debugging purposes, which bounces back the command so that arbitrary values testing is possible.
a = FakeAdapter() assert a.read() == "" a.write("5") assert a.read() == "5" assert a.read() == "" assert a.ask("10") == "10" assert a.values("10") == [10]
- ask(command)
Write the command to the instrument and returns the resulting ASCII response.
Deprecated since version 0.11: Call Instrument.ask instead.
- Parameters
command – SCPI command string to be sent to the instrument
- Returns
String ASCII response of the instrument
- binary_values(command, header_bytes=0, dtype=<class 'numpy.float32'>)
Returns a numpy array from a query for binary data
Deprecated since version 0.11: Call Instrument.binary_values instead.
- Parameters
command – SCPI command to be sent to the instrument
header_bytes – Integer number of bytes to ignore in header
dtype – The NumPy data type to format the values with
- Returns
NumPy array of values
- close()
Close the connection.
- flush_read_buffer()
Flush and discard the input buffer. Implement in subclass.
- read(**kwargs)
Read up to (excluding) read_termination or the whole read buffer.
Do not override in a subclass!
- Parameters
**kwargs – Keyword arguments for the connection itself.
- Returns str
ASCII response of the instrument (excluding read_termination).
- read_binary_values(header_bytes=0, termination_bytes=None, dtype=<class 'numpy.float32'>, **kwargs)
Returns a numpy array from a query for binary data
- Parameters
header_bytes (int) – Number of bytes to ignore in header.
termination_bytes (int) – Number of bytes to strip at end of message or None.
dtype – The NumPy data type to format the values with.
**kwargs – Further arguments for the NumPy fromstring method.
- Returns
NumPy array of values
- read_bytes(count=-1, break_on_termchar=False, **kwargs)
Read a certain number of bytes from the instrument.
Do not override in a subclass!
- Parameters
count (int) – Number of bytes to read. A value of -1 indicates to read from the whole read buffer.
break_on_termchar (bool) – Stop reading at a termination character.
**kwargs – Keyword arguments for the connection itself.
- Returns bytes
Bytes response of the instrument (including termination).
- values(command, separator=', ', cast=<class 'float'>, preprocess_reply=None)
Write a command to the instrument and returns a list of formatted values from the result.
Deprecated since version 0.11: Call Instrument.values instead.
- Parameters
command – SCPI command to be sent to the instrument
separator – A separator character to split the string into a list
cast – A type to cast the result
preprocess_reply – optional callable used to preprocess values received from the instrument. The callable returns the processed string. If not specified, the Adapter default is used if available, otherwise no preprocessing is done.
- Returns
A list of the desired type, or strings where the casting fails
- write(command, **kwargs)
Write a string command to the instrument appending write_termination.
Do not override in a subclass!
- Parameters
command (str) – Command string to be sent to the instrument (without termination).
**kwargs – Keyword arguments for the connection itself.
- write_binary_values(command, values, termination='', **kwargs)
Write binary data to the instrument, e.g. waveform for signal generators
- Parameters
command – command string to be sent to the instrument
values – iterable representing the binary values
termination – String added afterwards to terminate the message.
**kwargs – Key-word arguments to pass onto
Adapter._format_binary_values()
- Returns
number of bytes written
- write_bytes(content, **kwargs)
Write the bytes content to the instrument.
Do not override in a subclass!
- Parameters
content (bytes) – The bytes to write to the instrument.
**kwargs – Keyword arguments for the connection itself.
- class pymeasure.generator.Generator
Generates tests from the communication with an instrument.
Example usage:
g = Generator() inst = g.instantiate(TC038, "COM5", 'hcp', adapter_kwargs={'baud_rate': 9600}) inst.information # returns the 'information' property and adds it to the tests inst.setpoint = 20 inst.setpoint == 20 # should be True g.write_file("test_tc038.py") # write the tests to a file
- instantiate(instrument_class, adapter, manufacturer, adapter_kwargs=None, **kwargs)
Instantiate the instrument and store the instantiation communication.
..note:
You have to give all keyword arguments necessary for adapter instantiation in `adapter_kwargs`, even those, which are defined somewhere in the instrument's ``__init__`` method, be it as a default value, be it directly in the ``Instrument.__init__()`` call.
- Parameters
instrument_class – Class of the instrument to test.
adapter – Adapter (instance or str) for the instrument instantiation.
manufacturer – Module from which to import the instrument, e.g. ‘hcp’ if instrument_class is ‘pymeasure.hcp.tc038’.
adapter_kwargs – Keyword arguments for the adapter instantiation (see note above).
**kwargs – Keyword arguments for the instrument instantiation.
- Returns
A man-in-the-middle instrument, which can be used like a normal instrument.
- parse_stream()
Parse the stream not yet read.
- test_method(method_name, *args, **kwargs)
Test calling the method_name of the instruments with args and kwargs.
- test_property_getter(property)
Test getting the property of the instrument, adding it to the list.
- test_property_setter(property, value)
Test setting the property of the instrument to value, adding it to the list.
- test_property_setter_batch(property, values)
Test setting property to each element in values.
- write_file(filename='tests.py')
Write the tests into the file.
- Parameters
filename – Name to save the tests to, may contain the path, e.g. “/tests/test_abc.py”.
- write_getter_test(file, property, parameters)
Write a getter test.
- write_init_test(file)
Write the header and init test.
- write_method_test(file, method, parameters)
Write a test for a method.
- write_method_tests(file)
Write all parametrized method tests in alphabetic order.
- write_property_tests(file)
Write tests for properties in alphabetic order.
If getter and setter exist, the setter is the first test.
- write_setter_test(file, property, parameters)
Write a setter test.