Source code for pyvisa.resources.gpib

# -*- coding: utf-8 -*-
"""
    pyvisa.resources.gpib
    ~~~~~~~~~~~~~~~~~~~~~

    High level wrapper for GPIB resources.

    This file is part of PyVISA.

    :copyright: 2014 by PyVISA Authors, see AUTHORS for more details.
    :license: MIT, see LICENSE for more details.
"""
import time
import sys

if sys.version_info > (3,2):
    perf_counter = time.perf_counter
else:
    perf_counter = time.clock

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


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

    def send_command(self, data):
        """Write GPIB command bytes on the bus.

        Corresponds to viGpibCommand function of the VISA library.

        :param data: data tor write.
        :type data: bytes
        :return: Number of written bytes, return value of the library call.
        :rtype: int, VISAStatus
        """
        return self.visalib.gpib_command(self.session, data)

    def control_atn(self, mode):
        """Specifies the state of the ATN line and the local active controller state.

        Corresponds to viGpibControlATN function of the VISA library.

        :param mode: Specifies the state of the ATN line and optionally the local active controller state.
                     (Constants.GPIB_ATN*)
        :return: return value of the library call.
        :rtype: VISAStatus
        """
        return self.visalib.gpib_control_atn(self.session, mode)

    def pass_control(self, primary_address, secondary_address):
        """Tell the GPIB device at the specified address to become controller in charge (CIC).

        Corresponds to viGpibPassControl function of the VISA library.

        :param primary_address: Primary address of the GPIB device to which you want to pass control.
        :param secondary_address: 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.
        :return: return value of the library call.
        :rtype: VISAStatus
        """
        return self.visalib.gpib_pass_control(self.session, primary_address, secondary_address)

    def send_ifc(self):
        """Pulse the interface clear line (IFC) for at least 100 microseconds.

        Corresponds to viGpibSendIFC function of the VISA library.

        :return: return value of the library call.
        :rtype: VISAStatus
        """
        return self.visalib.gpib_send_ifc(self.session)


[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`. """
[docs] def wait_for_srq(self, timeout=25000): """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. :param timeout: the maximum waiting time in milliseconds. Defaul: 25000 (milliseconds). None means waiting forever if necessary. """ self.enable_event(constants.VI_EVENT_SERVICE_REQ, constants.VI_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.VI_EVENT_SERVICE_REQ, adjusted_timeout) if self.stb & 0x40: break self.discard_events(constants.VI_EVENT_SERVICE_REQ, constants.VI_QUEUE)
[docs]@Resource.register(constants.InterfaceType.gpib, 'INTFC') class GPIBInterface(_GPIBMixin, Resource): """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`. """
[docs] def group_execute_trigger(self, *resources): 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))
[docs] def flush(self, mask): """Manually clears the specified buffers. Depending on the mask this can cause the buffer data to be written to the device. :param mask: Specifies the action to be taken with flushing the buffer. See highlevel.VisaLibraryBase.flush for a detailed description. """ self.visalib.flush(self.session, mask)