Source code for pyvisa.resources.gpib

# -*- coding: utf-8 -*-
"""High level wrapper for GPIB resources.

This file is part of PyVISA.

:copyright: 2014-2022 by PyVISA Authors, see AUTHORS for more details.
:license: MIT, see LICENSE for more details.

"""
from time import perf_counter
from typing import Tuple

from .. import attributes, constants
from ..attributes import Attribute
from .messagebased import ControlRenMixin, MessageBasedResource
from .resource import Resource


class _GPIBMixin(ControlRenMixin):
    """Common attributes and methods of GPIB Instr and Interface."""

    #: Primary address of the GPIB device used by the given session.
    primary_address: Attribute[int] = attributes.AttrVI_ATTR_GPIB_PRIMARY_ADDR()

    #: Secondary address of the GPIB device used by the given session.
    secondary_address: Attribute[int] = attributes.AttrVI_ATTR_GPIB_SECONDARY_ADDR()

    #: Current state of the GPIB REN (Remote ENable) interface line.
    remote_enabled: Attribute[
        constants.LineState
    ] = attributes.AttrVI_ATTR_GPIB_REN_STATE()


[docs] @Resource.register(constants.InterfaceType.gpib, "INSTR") class GPIBInstrument(_GPIBMixin, MessageBasedResource): """Communicates with to devices of type GPIB::<primary address>[::INSTR] More complex resource names can be specified with the following grammar: GPIB[board]::primary address[::secondary address][::INSTR] Do not instantiate directly, use :meth:`pyvisa.highlevel.ResourceManager.open_resource`. """ #: Whether to unaddress the device (UNT and UNL) after each read or write operation. enable_unaddressing: Attribute[bool] = attributes.AttrVI_ATTR_GPIB_UNADDR_EN() #: Whether to use repeat addressing before each read or write operation. enable_repeat_addressing: Attribute[bool] = attributes.AttrVI_ATTR_GPIB_READDR_EN()
[docs] def wait_for_srq(self, timeout: int = 25000) -> None: """Wait for a serial request (SRQ) coming from the instrument. Note that this method is not ended when *another* instrument signals an SRQ, only *this* instrument. Parameters ---------- timeout : int Maximum waiting time in milliseconds. Defaul: 25000 (milliseconds). None means waiting forever if necessary. """ self.enable_event( constants.EventType.service_request, constants.EventMechanism.queue ) if timeout and not (0 <= timeout <= 4294967295): raise ValueError("timeout value is invalid") starting_time = perf_counter() while True: if timeout is None: adjusted_timeout = constants.VI_TMO_INFINITE else: adjusted_timeout = int( (starting_time + timeout / 1e3 - perf_counter()) * 1e3 ) if adjusted_timeout < 0: adjusted_timeout = 0 self.wait_on_event(constants.EventType.service_request, adjusted_timeout) if self.stb & 0x40: break self.discard_events( constants.EventType.service_request, constants.EventMechanism.queue )
[docs] @Resource.register(constants.InterfaceType.gpib, "INTFC") class GPIBInterface(_GPIBMixin, MessageBasedResource): """Communicates with to devices of type GPIB::INTFC More complex resource names can be specified with the following grammar: GPIB[board]::INTFC Do not instantiate directly, use :meth:`pyvisa.highlevel.ResourceManager.open_resource`. """ #: Is the specified GPIB interface currently the system controller. is_system_controller: Attribute[ bool ] = attributes.AttrVI_ATTR_GPIB_SYS_CNTRL_STATE() #: Is the specified GPIB interface currently CIC (Controller In Charge). is_controller_in_charge: Attribute[bool] = attributes.AttrVI_ATTR_GPIB_CIC_STATE() #: Current state of the GPIB ATN (ATtentioN) interface line. atn_state: Attribute[constants.LineState] = attributes.AttrVI_ATTR_GPIB_ATN_STATE() #: Current state of the GPIB NDAC (Not Data ACcepted) interface line. ndac_state: Attribute[ constants.LineState ] = attributes.AttrVI_ATTR_GPIB_NDAC_STATE() #: Is the GPIB interface currently addressed to talk or listen, or is not addressed. address_state: Attribute[ constants.LineState ] = attributes.AttrVI_ATTR_GPIB_ADDR_STATE()
[docs] def send_command(self, data: bytes) -> Tuple[int, constants.StatusCode]: """Write GPIB command bytes on the bus. Corresponds to viGpibCommand function of the VISA library. Parameters ---------- data : bytes Command to write. Returns ------- int Number of bytes written constants.StatusCode Return value of the library call. """ return self.visalib.gpib_command(self.session, data)
[docs] def control_atn(self, mode: constants.ATNLineOperation) -> constants.StatusCode: """Specifies the state of the ATN line and the local active controller state. Corresponds to viGpibControlATN function of the VISA library. Parameters ---------- mode : constants.ATNLineOperation Specifies the state of the ATN line and optionally the local active controller state. Returns ------- constants.StatusCode Return value of the library call. """ return self.visalib.gpib_control_atn(self.session, mode)
[docs] def pass_control( self, primary_address: int, secondary_address: int ) -> constants.StatusCode: """Tell a GPIB device to become controller in charge (CIC). Corresponds to viGpibPassControl function of the VISA library. Parameters ---------- primary_address : int Primary address of the GPIB device to which you want to pass control. secondary_address : int Secondary address of the targeted GPIB device. If the targeted device does not have a secondary address, this parameter should contain the value Constants.NO_SEC_ADDR. Returns ------- constants.StatusCode Return value of the library call. """ return self.visalib.gpib_pass_control( self.session, primary_address, secondary_address )
[docs] def send_ifc(self) -> constants.StatusCode: """Pulse the interface clear line (IFC) for at least 100 microseconds. Corresponds to viGpibSendIFC function of the VISA library. """ return self.visalib.gpib_send_ifc(self.session)
[docs] def group_execute_trigger( self, *resources: GPIBInstrument ) -> Tuple[int, constants.StatusCode]: """ Parameters ---------- resources : GPIBInstrument GPIB resources to which to send the group trigger. Returns ------- int Number of bytes written as part of sending the GPIB commands. constants.StatusCode Return value of the library call. """ for resource in resources: if not isinstance(resource, GPIBInstrument): raise ValueError("%r is not a GPIBInstrument", resource) # TODO: check that all resources are in the same board. if not self.is_controller_in_charge: self.send_ifc() command = [ 0x40, 0x20 + 31, ] # broadcast TAD#0 and "UNL" (don't listen) to all devices for resource in resources: # tell device GPIB::11 to listen command.append(0x20 + resource.primary_address) # send GET ('group execute trigger') command.append(0x08) return self.send_command(bytes(command))