Add remote/local handling for VXI-11 and HiSLIP

CHANGES

@@ -4,6 +4,7 @@ PyVISA-py Changelog
 0.9.0 (unreleased)
 ------------------
 
+- VXI-11 and HiSLIP: add support for remote/local #627 PR #636
 - A VXI-11 read stopped by both the END indicator and the termination
   character now reports ``VI_SUCCESS`` rather than
   ``VI_SUCCESS_TERM_CHAR``. VPP-4.3 RULE 6.1.1 gives END priority over the

docs/source/faq.rst

@@ -181,6 +181,32 @@ omit the argument.
     wait on a lock".  Set ``lock_timeout`` on the session for that, as in the
     DM3068 example above.
 
+Remote/Local control
+--------------------
+
+Setting an instrument to Remote or Local is possible via VXI-11, HiSLIP and GPIB.
+
+In PyVISA, this is done through ``inst.control_ren(pyvisa.constants.RENLineOperation.{op})``
+where valid ``{op}`` values are:
+
+================  ===========  =========================================
+RENLineOperation  VXI-11       HiSLIP
+================  ===========  =========================================
+address_gtl       goto local   goto local, no change to remote enable
+asrt              error        enable remote
+asrt_address      goto remote  enable remote, goto remote
+asrt_address_llo  goto remote  enable remote, goto remote, local lockout
+asrt_llo          error        enable remote, local lockout
+deassert          error        disable remote
+deassert_gtl      goto local   disable remote, goto local
+================  ===========  =========================================
+
+This is fully conform to what VPP-4.3 Rule 6.5.6 and Observations 6.5.1 + 6.5.2 say,
+and what NI-VISA does, so this should be fully portable.
+
+GPIB has functionality comparable to HiSLIP, but may behave differently than NI-VISA, 
+depending on the type of interface.
+
 
 .. _PySerial: https://pythonhosted.org/pyserial/
 .. _PyVISA: http://pyvisa.readthedocs.org/

pyvisa_py/tcpip.py

@@ -315,6 +315,44 @@ def write(self, data: bytes) -> Tuple[int, StatusCode]:
 
         return len(data), StatusCode.success
 
+    def gpib_control_ren(self, mode: constants.RENLineOperation) -> StatusCode:
+        """Controls the state of the GPIB Remote Enable (REN) interface line.
+
+        Optionally the remote/local state of the device is also controlled.
+
+        Corresponds to viGpibControlREN function of the VISA library.
+
+        Parameters
+        ----------
+        mode : constants.RENLineOperation
+            Specifies the state of the REN line and optionally the device
+            remote/local state.
+
+        Returns
+        -------
+        StatusCode
+            Return value of the library call.
+
+        """
+        try:
+            method = {
+                constants.RENLineOperation.address_gtl: "justGTL",
+                constants.RENLineOperation.asrt: "enableRemote",
+                constants.RENLineOperation.asrt_address: "enableAndGotoRemote",
+                constants.RENLineOperation.asrt_address_llo: "enableAndGTRLLO",
+                constants.RENLineOperation.asrt_llo: "enableAndLockoutLocal",
+                constants.RENLineOperation.deassert: "disableRemote",
+                constants.RENLineOperation.deassert_gtl: "disableAndGTL",
+            }[mode]
+        except:
+            # unknown value?
+            return StatusCode.error_nonsupported_operation
+
+        interface = cast(hislip.Instrument, self.interface)
+        interface.async_remote_local_control(method)
+
+        return StatusCode.success
+
     def clear(self) -> StatusCode:
         """Clears a device.
 
@@ -853,6 +891,47 @@ def write(self, data: bytes) -> Tuple[int, StatusCode]:
         except vxi11.Vxi11Error:
             return 0, StatusCode.error_timeout
 
+    def gpib_control_ren(self, mode: constants.RENLineOperation) -> StatusCode:
+        """Controls the state of the GPIB Remote Enable (REN) interface line.
+
+        Optionally the remote/local state of the device is also controlled.
+
+        Corresponds to viGpibControlREN function of the VISA library.
+
+        Parameters
+        ----------
+        mode : constants.RENLineOperation
+            Specifies the state of the REN line and optionally the device
+            remote/local state.
+
+        Returns
+        -------
+        StatusCode
+            Return value of the library call.
+
+        """
+        if mode not in (
+            constants.RENLineOperation.address_gtl,
+            constants.RENLineOperation.asrt_address,
+            constants.RENLineOperation.asrt_address_llo,
+            constants.RENLineOperation.deassert_gtl,
+        ):
+            return constants.StatusCode.error_nonsupported_operation
+
+        if mode in (
+            constants.RENLineOperation.asrt_address,
+            constants.RENLineOperation.asrt_address_llo,
+        ):
+            error = self.interface.device_remote(
+                self.link, 0, self.lock_timeout, self._io_timeout
+            )
+        else:
+            error = self.interface.device_local(
+                self.link, 0, self.lock_timeout, self._io_timeout
+            )
+
+        return VXI11_ERRORS_TO_VISA[error]
+
     def _get_attribute(self, attribute: ResourceAttribute) -> Tuple[Any, StatusCode]:
         """Get the value for a given VISA attribute for this session.
 

pyvisa_py/testsuite/test_remote_local.py

@@ -0,0 +1,90 @@
+# -*- coding: utf-8 -*-
+"""Unit tests for VXI11 and hislip remote/local operations."""
+
+from __future__ import annotations
+
+from unittest.mock import MagicMock
+
+import pytest
+
+from pyvisa import constants
+from pyvisa_py.tcpip import TCPIPInstrHiSLIP, TCPIPInstrVxi11
+
+
+@pytest.mark.parametrize(
+    "mode, expected_method",
+    [
+        (constants.RENLineOperation.address_gtl, "device_local"),
+        (constants.RENLineOperation.asrt_address, "device_remote"),
+        (constants.RENLineOperation.asrt_address_llo, "device_remote"),
+        (constants.RENLineOperation.deassert_gtl, "device_local"),
+    ],
+)
+def test_vxi11_gpib_control_ren_calls_expected_device_method(mode, expected_method):
+    session = object.__new__(TCPIPInstrVxi11)
+    session.interface = MagicMock()
+    session.link = 7
+    session.lock_timeout = 1234
+    session._io_timeout = 5678
+
+    session.interface.device_local.return_value = 0
+    session.interface.device_remote.return_value = 0
+
+    assert session.gpib_control_ren(mode) == constants.StatusCode.success
+
+    getattr(session.interface, expected_method).assert_called_once_with(
+        session.link, 0, session.lock_timeout, session._io_timeout
+    )
+
+    if expected_method == "device_remote":
+        session.interface.device_local.assert_not_called()
+    else:
+        session.interface.device_remote.assert_not_called()
+
+
+@pytest.mark.parametrize("invalid_mode", [-1, 999, "bogus", None, object()])
+def test_vxi11_gpib_control_ren_rejects_unsupported_modes(invalid_mode):
+    session = object.__new__(TCPIPInstrVxi11)
+    session.interface = MagicMock()
+    session.link = 7
+    session.lock_timeout = 1234
+    session._io_timeout = 5678
+
+    assert session.gpib_control_ren(invalid_mode) == (
+        constants.StatusCode.error_nonsupported_operation
+    )
+    session.interface.device_local.assert_not_called()
+    session.interface.device_remote.assert_not_called()
+
+
+@pytest.mark.parametrize(
+    "mode, expected_method",
+    [
+        (constants.RENLineOperation.address_gtl, "justGTL"),
+        (constants.RENLineOperation.asrt, "enableRemote"),
+        (constants.RENLineOperation.asrt_address, "enableAndGotoRemote"),
+        (constants.RENLineOperation.asrt_address_llo, "enableAndGTRLLO"),
+        (constants.RENLineOperation.asrt_llo, "enableAndLockoutLocal"),
+        (constants.RENLineOperation.deassert, "disableRemote"),
+        (constants.RENLineOperation.deassert_gtl, "disableAndGTL"),
+    ],
+)
+def test_hislip_gpib_control_ren_calls_expected_interface_method(mode, expected_method):
+    session = object.__new__(TCPIPInstrHiSLIP)
+    session.interface = MagicMock()
+
+    assert session.gpib_control_ren(mode) == constants.StatusCode.success
+    session.interface.async_remote_local_control.assert_called_once_with(
+        expected_method
+    )
+
+
+@pytest.mark.parametrize("invalid_mode", [-1, 999, "bogus", None, object()])
+def test_hislip_gpib_control_ren_rejects_unsupported_modes(invalid_mode):
+    session = object.__new__(TCPIPInstrHiSLIP)
+    session.interface = MagicMock()
+
+    assert session.gpib_control_ren(invalid_mode) == (
+        constants.StatusCode.error_nonsupported_operation
+    )
+    session.interface.async_remote_local_control.assert_not_called()