migrate siglent power backend vxi11 -> pyvisa, add power show/config options

doc/configuration.rst

@@ -247,8 +247,12 @@ Currently available are:
   for details.
 
 ``siglent``
-  Controls *Siglent SPD3000X* series modules via the `vxi11 Python module
-  <https://pypi.org/project/python-vxi11/>`_.
+  Controls *Siglent SPD3000X* series modules via the `PyVISA Python module
+  <https://pypi.org/project/PyVISA/>`_ (with the ``pyvisa-py`` backend).
+  In addition to switching the output on and off, this backend supports
+  reading and configuring the per-channel voltage and current limits and
+  reading the measured voltage, current and power (see the ``show`` and
+  ``config`` actions of ``labgrid-client power``).
 
 ``simplerest``
   This is a generic backend for PDU implementations which can be controlled via
@@ -2424,6 +2428,13 @@ Implements:
 Arguments:
   - delay (float, default=2.0): delay in seconds between off and on
 
+Some programmable power supplies (currently the ``siglent`` backend) additionally
+implement :any:`ProgrammablePowerProtocol`, which allows reading the measured
+voltage, current and power and configuring the voltage and current limits. These
+are exposed via the ``show`` and ``config`` actions of ``labgrid-client power``
+(see :ref:`usage-power` for details). Backends that do not implement this
+protocol simply do not provide those actions.
+
 PDUDaemonDriver
 ~~~~~~~~~~~~~~~
 A :any:`PDUDaemonDriver` controls a `PDUDaemonPort`_, allowing control of the

doc/development.rst

@@ -160,6 +160,24 @@ The minimum requirement is a call to :code:`super().__attrs_post_init__()`.
 All that's left now is to implement the functionality described by the used
 protocol, by using the API of the bound drivers and resources.
 
+Programmable Power Supplies
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Simple power drivers only implement :any:`PowerProtocol` (``on``, ``off``,
+``cycle`` and ``get``). Power supplies that can additionally report and
+configure their output implement :any:`ProgrammablePowerProtocol`, which
+extends :any:`PowerProtocol` with three methods:
+
+- ``show()`` returns a dict with the measured ``voltage``, ``amps`` and
+  ``watts`` as well as the configured ``v_limit`` and ``a_limit``.
+- ``voltage(value)`` sets the output voltage.
+- ``amps(value)`` sets the output current limit.
+
+For the :any:`NetworkPowerDriver`, these are dispatched to the configured
+backend module, which has to provide matching ``power_show``,
+``power_voltage`` and ``power_amps`` functions (see
+``labgrid/driver/power/siglent.py`` for a reference implementation).
+
 Writing a Resource
 -------------------
 

doc/usage.rst

@@ -166,6 +166,44 @@ allocated before returning.
 A reservation will time out after a short time, if it is neither refreshed nor
 used by locked places.
 
+.. _usage-power:
+
+Controlling Power
+~~~~~~~~~~~~~~~~~
+
+The ``labgrid-client power`` command (short alias ``pw``) switches a place's
+power on and off:
+
+.. code-block:: bash
+
+  $ labgrid-client -p my-place power on
+  $ labgrid-client -p my-place power off
+  $ labgrid-client -p my-place power cycle
+  $ labgrid-client -p my-place power get
+
+For programmable power supplies (currently the ``siglent`` backend of
+:any:`NetworkPowerPort`), two additional actions are available.
+
+``power config`` sets the voltage and/or current limit:
+
+.. code-block:: bash
+
+  $ labgrid-client -p my-place power config --voltage 5.0 --amps 1.5
+  set voltage to 5.0V
+  set amps to 1.5A
+
+``power show`` reads back the measured voltage, current and power together with
+the configured limits (shown in square brackets):
+
+.. code-block:: bash
+
+  $ labgrid-client -p my-place power show
+  Voltage: 5.001V [5.0V], Current: 0.209A [1.5A], Power: 1.045W
+
+The power value is read directly from the device rather than being computed from
+voltage times current, so it stays accurate even though those two values are
+sampled at slightly different times.
+
 Library
 -------
 labgrid can be used directly as a Python library, without the infrastructure

labgrid/driver/power/siglent.py

@@ -1,35 +1,77 @@
-"""tested with Siglent SPD3303X-E, and should be compatible with all SPD3000X series modules"""
+""" tested with Siglent SPD3303X-E, SPD1168X and should be compatible with all SPD3000X series modules """
 
-import warnings
-
-import vxi11
+import pyvisa
 
+def _get_psu(host):
+    """Helper to initialize the raw network socket resource session via PyVISA."""
+    rm = pyvisa.ResourceManager("@py")
+    resource_string = f"TCPIP0::{host}::5025::SOCKET"
+    psu = rm.open_resource(resource_string)
+    # Siglent scopes and PSUs require explicit newline termination on raw sockets
+    psu.read_termination = "\n"
+    psu.write_termination = "\n"
+    psu.timeout = 5000  # 5 second safety timeout
+    return psu
 
 def power_set(host, port, index, value):
-    warnings.warn(
-        "siglent power backend uses vxi11 module using deprecated xdrlib module, see https://github.com/labgrid-project/labgrid/issues/1507",
-        DeprecationWarning,
-    )
-
     assert port is None
     index = int(index)
     assert 1 <= index <= 2
     value = "ON" if value else "OFF"
-    psu = vxi11.Instrument(host)
-    psu.write(f"OUTPUT CH{index},{value}")
-
+    with _get_psu(host) as psu:
+        psu.write(f"OUTPUT CH{index},{value}")
 
 def power_get(host, port, index):
-    warnings.warn(
-        "siglent power backend uses vxi11 module using deprecated xdrlib module, see https://github.com/labgrid-project/labgrid/issues/1507",
-        DeprecationWarning,
-    )
-
     assert port is None
     index = int(index)
     assert 1 <= index <= 2
-    psu = vxi11.Instrument(host)
-    state = psu.ask("SYSTEM:STATUS?")
+    with _get_psu(host) as psu:
+        state = psu.query("SYSTEM:STATUS?")
     state = int(state, 16)
     bitmask = 1 << (index + 3)
     return bool(state & bitmask)
+
+def power_show(host, port, index):
+    assert port is None
+    index = int(index)
+    assert 1 <= index <= 2
+    with _get_psu(host) as psu:
+        v_measured = psu.query(f"MEAS:VOLT? CH{index}")
+        a_measured = psu.query(f"MEAS:CURR? CH{index}")
+        w_measured = psu.query(f"MEAS:POWE? CH{index}")
+        v_set = psu.query(f"CH{index}:VOLT?")
+        a_set = psu.query(f"CH{index}:CURR?")
+    return {
+        "voltage": float(v_measured),
+        "amps": float(a_measured),
+        "watts": float(w_measured),
+        "v_limit": float(v_set),
+        "a_limit": float(a_set)
+    }
+
+def power_watts(host, port, index):
+    """Read the power (in watts) measured by the device on the given channel.
+
+    The PSU reports true power directly, so this avoids errors from
+    multiplying voltage and current sampled at slightly different times.
+    """
+    assert port is None
+    index = int(index)
+    assert 1 <= index <= 2
+    with _get_psu(host) as psu:
+        w_measured = psu.query(f"MEAS:POWE? CH{index}")
+    return float(w_measured)
+
+def power_voltage(host, port, index, voltage):
+    assert port is None
+    index = int(index)
+    assert 1 <= index <= 2
+    with _get_psu(host) as psu:
+        psu.write(f"CH{index}:VOLT {voltage}")
+
+def power_amps(host, port, index, amps):
+    assert port is None
+    index = int(index)
+    with _get_psu(host) as psu:
+        psu.write(f"CH{index}:CURR {amps}")
+

labgrid/driver/powerdriver.py

@@ -7,7 +7,7 @@
 
 from ..exceptions import InvalidConfigError
 from ..factory import target_factory
-from ..protocol import PowerProtocol, DigitalOutputProtocol, ResetProtocol
+from ..protocol import PowerProtocol, DigitalOutputProtocol, ResetProtocol, ProgrammablePowerProtocol
 from ..resource import NetworkPowerPort
 from ..step import step
 from ..util.proxy import proxymanager
@@ -233,6 +233,21 @@ def cycle(self):
     def get(self):
         return self.backend.power_get(self._host, self._port, self.port.index)
 
+    @Driver.check_active
+    @step()
+    def show(self):
+        return self.backend.power_show(self._host, self._port, self.port.index)
+
+    @Driver.check_active
+    @step(args=['voltage'])
+    def voltage(self, voltage):
+        return self.backend.power_voltage(self._host, self._port, self.port.index, voltage)
+
+    @Driver.check_active
+    @step(args=['amps'])
+    def amps(self, amps):
+        return self.backend.power_amps(self._host, self._port, self.port.index, amps)
+
 @target_factory.reg_driver
 @attr.s(eq=False)
 class DigitalOutputPowerDriver(Driver, PowerResetMixin, PowerProtocol):

labgrid/protocol/__init__.py

@@ -2,7 +2,7 @@
 from .commandprotocol import CommandProtocol
 from .consoleprotocol import ConsoleProtocol
 from .linuxbootprotocol import LinuxBootProtocol
-from .powerprotocol import PowerProtocol
+from .powerprotocol import PowerProtocol, ProgrammablePowerProtocol
 from .filetransferprotocol import FileTransferProtocol
 from .infoprotocol import InfoProtocol
 from .digitaloutputprotocol import DigitalOutputProtocol

labgrid/protocol/powerprotocol.py

@@ -13,3 +13,17 @@ def off(self):
     @abc.abstractmethod
     def cycle(self):
         raise NotImplementedError
+
+
+class ProgrammablePowerProtocol(PowerProtocol):
+    @abc.abstractmethod
+    def show(self, index):
+        raise NotImplementedError
+
+    @abc.abstractmethod
+    def voltage(self, index, voltage):
+        raise NotImplementedError
+
+    @abc.abstractmethod
+    def amps(self, index, amps):
+        raise NotImplementedError

labgrid/remote/client.py

@@ -971,9 +971,29 @@ def power(self):
             raise UserError("target has no compatible resource available")
         if delay is not None:
             drv.delay = delay
+
+        if action == "config":
+            if self.args.voltage is None and self.args.amps is None:
+                raise UserError("Option config requires --voltage <float> and/or --amps <float>")
+
+            if self.args.voltage is not None:
+                drv.voltage(self.args.voltage)
+                print(f"set voltage to {self.args.voltage}V")
+            if self.args.amps is not None:
+                drv.amps(self.args.amps)
+                print(f"set amps to {self.args.amps}A")
+            return
+
         res = getattr(drv, action)()
         if action == "get":
             print(f"power{' ' + name if name else ''} for place {place.name} is {'on' if res else 'off'}")
+        elif action == "show":
+            print(
+                f"Voltage: {res['voltage']}V [{res['v_limit']}V], "
+                f"Current: {res['amps']}A [{res['a_limit']}A], "
+                f"Power: {res['watts']}W"
+            )
+
 
     def digital_io(self):
         place = self.get_acquired_place()
@@ -1982,10 +2002,16 @@ def get_parser(auto_doc_mode=False) -> "argparse.ArgumentParser | AutoProgramArg
     subparser.set_defaults(func=ClientSession.print_env)
 
     subparser = subparsers.add_parser("power", aliases=("pw",), help="change (or get) a place's power status")
-    subparser.add_argument("action", choices=["on", "off", "cycle", "get"])
+    subparser.add_argument("action", choices=["on", "off", "cycle", "get", "show", "config"])
     subparser.add_argument(
         "-t", "--delay", type=float, default=None, help="wait time in seconds between off and on during cycle"
     )
+    subparser.add_argument(
+        "-v", "--voltage", type=float, default=None, help="voltage value to be configured"
+    )
+    subparser.add_argument(
+        "-a", "--amps", type=float, default=None, help="amps value to be configured"
+    )
     subparser.add_argument("--name", "-n", help="optional resource name")
     subparser.set_defaults(func=ClientSession.power)
 

man/labgrid-client.1

@@ -556,7 +556,8 @@ change (or get) a place\(aqs power status
 .INDENT 3.5
 .sp
 .EX
-usage: labgrid\-client power|pw [\-t DELAY] [\-\-name NAME] {on,off,cycle,get}
+usage: labgrid\-client power|pw [\-t DELAY] [\-v VOLTAGE] [\-a AMPS] [\-\-name NAME]
+                               {on,off,cycle,get,show,config}
 .EE
 .UNINDENT
 .UNINDENT
@@ -571,6 +572,16 @@ wait time in seconds between off and on during cycle
 .UNINDENT
 .INDENT 0.0
 .TP
+.B \-v <voltage>, \-\-voltage <voltage>
+voltage value to be configured
+.UNINDENT
+.INDENT 0.0
+.TP
+.B \-a <amps>, \-\-amps <amps>
+amps value to be configured
+.UNINDENT
+.INDENT 0.0
+.TP
 .B \-\-name <name>, \-n <name>
 optional resource name
 .UNINDENT