Resource Manager

class pyvisa.highlevel.ResourceInfo(interface_type, interface_board_number, resource_class, resource_name, alias)

Resource extended information

Named tuple with information about a resource. Returned by some ResourceManager methods.

Interface_type:Interface type of the given resource string. pyvisa.constants.InterfaceType
Interface_board_number:
 Board number of the interface of the given resource string. We allow None since serial resources may not sometimes be easily described by a single number in particular on Linux system.
Resource_class:Specifies the resource class (for example, “INSTR”) of the given resource string.
Resource_name:This is the expanded version of the given resource string. The format should be similar to the VISA-defined canonical resource name.
Alias:Specifies the user-defined alias for the given resource string.
class pyvisa.highlevel.ResourceManager[source]

VISA Resource Manager.

close() → None[source]

Close the resource manager session.

last_status

Last status code returned for an operation with this Resource Manager.

list_resources(query: str = '?*::INSTR') → Tuple[str, ...][source]

Return a tuple of all connected devices matching query.

Notes

The query uses the VISA Resource Regular Expression syntax - which is not the same as the Python regular expression syntax. (see below)

The VISA Resource Regular Expression syntax is defined in the VISA Library specification: http://www.ivifoundation.org/docs/vpp43.pdf

Symbol Meaning ———- ———-

? Matches any one character.

Makes the character that follows it an ordinary character
instead of special character. For example, when a question mark follows a backslash (?), it matches the ? character instead of any one character.
[list] Matches any one character from the enclosed list. You can
use a hyphen to match a range of characters.
[^list] Matches any character not in the enclosed list. You can use
a hyphen to match a range of characters.
  • Matches 0 or more occurrences of the preceding character or expression.
  • Matches 1 or more occurrences of the preceding character or expression.
Exp|exp Matches either the preceding or following expression. The or
operator | matches the entire expression that precedes or follows it and not just the character that precedes or follows it. For example, VXI|GPIB means (VXI)|(GPIB), not VX(I|G)PIB.

(exp) Grouping characters or expressions.

Thus the default query, ‘?*::INSTR’, matches any sequences of characters ending ending with ‘::INSTR’.

On some platforms, devices that are already open are not returned.

list_resources_info(query: str = '?*::INSTR') → Dict[str, pyvisa.highlevel.ResourceInfo][source]

Get extended information about all connected devices matching query.

For details of the VISA Resource Regular Expression syntax used in query, refer to list_resources().

Returns:Mapping of resource name to ResourceInfo
Return type:Dict[str, ResourceInfo]
open_bare_resource(resource_name: str, access_mode: pyvisa.constants.AccessModes = <AccessModes.no_lock: 0>, open_timeout: int = 0) → Tuple[NewType.<locals>.new_type, pyvisa.constants.StatusCode][source]

Open the specified resource without wrapping into a class.

Parameters:
  • resource_name (str) – Name or alias of the resource to open.
  • access_mode (constants.AccessModes, optional) – Specifies the mode by which the resource is to be accessed, by default constants.AccessModes.no_lock
  • open_timeout (int, optional) – If the access_mode parameter requests a lock, then this parameter specifies the absolute time period (in milliseconds) that the resource waits to get unlocked before this operation returns an error, by default constants.VI_TMO_IMMEDIATE.
Returns:

  • VISASession – Unique logical identifier reference to a session.
  • StatusCode – Return value of the library call.
open_resource(resource_name: str, access_mode: pyvisa.constants.AccessModes = <AccessModes.no_lock: 0>, open_timeout: int = 0, resource_pyclass: Optional[Type[Resource]] = None, **kwargs) → Resource[source]

Return an instrument for the resource name.

Parameters:
  • resource_name (str) – Name or alias of the resource to open.
  • access_mode (constants.AccessModes, optional) – Specifies the mode by which the resource is to be accessed, by default constants.AccessModes.no_lock
  • open_timeout (int, optional) – If the access_mode parameter requests a lock, then this parameter specifies the absolute time period (in milliseconds) that the resource waits to get unlocked before this operation returns an error, by default constants.VI_TMO_IMMEDIATE.
  • resource_pyclass (Optional[Type[Resource]], optional) – Resource Python class to use to instantiate the Resource. Defaults to None: select based on the resource name.
  • kwargs (Any) – Keyword arguments to be used to change instrument attributes after construction.
Returns:

Subclass of Resource matching the resource.
Return type:

Resource
resource_info(resource_name: str, extended: bool = True) → pyvisa.highlevel.ResourceInfo[source]

Get the (extended) information of a particular resource.

Parameters:
  • resource_name (str) – Unique symbolic name of a resource.
  • extended (bool, optional) – Also get extended information (ie. resource_class, resource_name, alias)
session

Resource Manager session handle.

Raises:errors.InvalidSession – Raised if the session is closed.