Add checks for signal current level and voltage level queries in Keysight E4980A driver

qcodes/instrument/sims/Keysight_E4980A.yaml

@@ -0,0 +1,37 @@
+spec: "1.0"
+devices:
+  device 1:
+    eom:
+      GPIB INSTR:
+        q: "\n"
+        r: "\n"
+    error: ERROR
+    dialogues:
+      - q: "*RST"
+      - q: "*CLS"
+      - q: "*OPT?"
+        r: "001"
+      - q: "*IDN?"
+        r: "Keysight Technologies,E4980A,MY46516036,A.02.10"
+
+    properties:
+
+      voltage_level:
+        default: 0
+        getter:
+          q: ":VOLTage:LEVel?"
+          r: "{}"
+        setter:
+          q: ":VOLTage:LEVel {}"
+
+      current_level:
+        default: 0
+        getter:
+          q: ":CURRent:LEVel?"
+          r: "{}"
+        setter:
+          q: ":CURRent:LEVel {}"
+
+resources:
+  GPIB::1::INSTR:
+    device: device 1

qcodes/instrument_drivers/Keysight/keysight_e4980a.py

@@ -2,7 +2,8 @@
 from distutils.version import LooseVersion
 
 from qcodes import VisaInstrument, InstrumentChannel
-from qcodes.instrument.parameter import MultiParameter, ParamRawDataType
+from qcodes.instrument.parameter import (MultiParameter, ParamRawDataType,
+                                         ManualParameter)
 from qcodes.utils.helpers import create_on_off_val_mapping
 from qcodes.utils.validators import Enum, Numbers, Bool, Ints
 from qcodes.instrument.group_parameter import GroupParameter, Group
@@ -188,8 +189,9 @@ def __init__(self,
 
         idn = self.IDN.get()
 
-        self.has_firmware_a_02_10_or_above = LooseVersion(idn["firmware"]) >=\
-                                             LooseVersion("A.02.10")
+        self.has_firmware_a_02_10_or_above = (
+                LooseVersion(idn["firmware"]) >= LooseVersion("A.02.10")
+        )
 
         self.has_option_001 = '001' in self._options()
         self._dc_bias_v_level_range: Union[Numbers, Enum]
@@ -224,19 +226,17 @@ def __init__(self,
 
         self.add_parameter(
             "current_level",
-            get_cmd=":CURRent:LEVel?",
-            set_cmd=":CURRent:LEVel {}",
-            get_parser=float,
+            get_cmd=self._get_current_level,
+            set_cmd=self._set_current_level,
             unit="A",
             vals=self._i_level_range,
             docstring="Gets and sets the current level for measurement signal."
         )
 
         self.add_parameter(
             "voltage_level",
-            get_cmd=":VOLTage:LEVel?",
-            set_cmd=":VOLTage:LEVel {}",
-            get_parser=float,
+            get_cmd=self._get_voltage_level,
+            set_cmd=self._set_voltage_level,
             unit="V",
             vals=self._v_level_range,
             docstring="Gets and sets the AC bias voltage level for measurement "
@@ -292,16 +292,15 @@ def __init__(self,
 
         self.add_parameter(
             "meas_time_mode",
-            initial_value="medium",
             val_mapping={"short": "SHOR", "medium": "MED", "long": "LONG"},
             parameter_class=GroupParameter
         )
 
         self.add_parameter(
             "averaging_rate",
-            initial_value=1,
             vals=Ints(1, 256),
             parameter_class=GroupParameter,
+            get_parser=int,
             docstring="Averaging rate for the measurement."
         )
 
@@ -325,11 +324,19 @@ def __init__(self,
                           "the BIAS field of the display."
             )
 
+        self.add_parameter(
+            "signal_mode",
+            initial_value=None,
+            vals=Enum("Voltage", "Current", None),
+            parameter_class=ManualParameter,
+            docstring="This parameter tracks the signal mode which is being "
+                      "set."
+        )
+
         self.add_submodule(
             "_correction",
             Correction4980A(self, "correction")
         )
-
         self.connect_message()
 
     @property
@@ -386,6 +393,46 @@ def _set_measurement(self,
         self._measurement_pair = measurement_pair
         self.write(f":FUNCtion:IMPedance {measurement_pair.name}")
 
+    def _get_voltage_level(self) -> float:
+        """
+        Gets voltage level if signal is set with voltage level parameter
+        otherwise raises an error.
+        """
+        if self.signal_mode() == "Current":
+            raise RuntimeError("Cannot get voltage level as signal is set "
+                               "with current level parameter.")
+
+        v_level = self.ask(":VOLTage:LEVel?")
+
+        return float(v_level)
+
+    def _set_voltage_level(self, val: str) -> None:
+        """
+        Sets voltage level
+        """
+        self.signal_mode("Voltage")
+        self.write(f":VOLTage:LEVel {val}")
+
+    def _set_current_level(self, val: str) -> None:
+        """
+        Sets current level
+        """
+        self.signal_mode("Current")
+        self.write(f":CURRent:LEVel {val}")
+
+    def _get_current_level(self) -> float:
+        """
+        Gets current level if signal is set with current level parameter
+        otherwise raises an error.
+        """
+        if self.signal_mode() == "Voltage":
+            raise RuntimeError("Cannot get current level as signal is set "
+                               "with voltage level parameter.")
+
+        i_level = self.ask(":CURRent:LEVel?")
+
+        return float(i_level)
+
     def _options(self) -> Tuple[str, ...]:
         """
         Returns installed options numbers. Combinations of different installed

qcodes/tests/drivers/test_keysight_e4980a.py

@@ -0,0 +1,57 @@
+import pytest
+import re
+
+import qcodes.instrument_drivers.Keysight.keysight_e4980a as E4980A
+import qcodes.instrument.sims as sims
+
+VISALIB = sims.__file__.replace('__init__.py', 'Keysight_E4980A.yaml@sim')
+
+
+@pytest.fixture(name="driver")
+def _make_driver():
+    instr = E4980A.KeysightE4980A('E4980A',
+                                  address="GPIB::1::INSTR",
+                                  visalib=VISALIB)
+    yield instr
+    instr.close()
+
+
+def test_idn(driver):
+    assert {'firmware': 'A.02.10',
+            'model': 'E4980A',
+            'serial': 'MY46516036',
+            'vendor': 'Keysight Technologies'} == driver.IDN()
+
+
+def test_raise_error_for_volt_level_query_when_signal_set_as_current(driver):
+    driver.current_level(0.01)
+    msg = re.escape("Cannot get voltage level as signal is set with current "
+                    "level parameter.")
+    with pytest.raises(RuntimeError, match=msg):
+        driver.voltage_level()
+
+
+def test_voltage_level_set_method(driver):
+    driver.voltage_level(3)
+    assert driver.voltage_level() == 3
+
+
+def test_signal_mode_parameter(driver):
+    driver.voltage_level(2)
+    assert driver.signal_mode() == "Voltage"
+
+    driver.current_level(0.005)
+    assert driver.signal_mode() == "Current"
+
+
+def test_raise_error_for_curr_level_query_when_signal_set_as_voltage(driver):
+    driver.voltage_level(1)
+    msg = re.escape("Cannot get current level as signal is set with voltage "
+                    "level parameter.")
+    with pytest.raises(RuntimeError, match=msg):
+        driver.current_level()
+
+
+def test_current_level_set_method(driver):
+    driver.current_level(0.003)
+    assert driver.current_level() == 0.003