Add servo instrument

ConnectionHandler.py

@@ -4,6 +4,7 @@
 import threading
 
 from pslab import ScienceLab
+from pslab.external.motor import Servo
 from pslab.instrument.logic_analyzer import LogicAnalyzer
 from pslab.instrument.multimeter import Multimeter
 from pslab.instrument.oscilloscope import Oscilloscope
@@ -51,3 +52,10 @@ def getLogicAnalyzer(self) -> LogicAnalyzer:
 
     def getMultimeter(self) -> Multimeter:
         return self.__getScienceLab().multimeter
+
+    def getServos(self, MinAnglePulse: int, MaxAnglePulse: int, AngleRange: int, Frequency: int) -> [Servo]:
+        pwm_generator = self.getPWMGenerator()
+        return [Servo("SQ1", pwm_generator, MinAnglePulse, MaxAnglePulse, AngleRange, Frequency),
+                Servo("SQ2", pwm_generator, MinAnglePulse, MaxAnglePulse, AngleRange, Frequency),
+                Servo("SQ3", pwm_generator, MinAnglePulse, MaxAnglePulse, AngleRange, Frequency),
+                Servo("SQ4", pwm_generator, MinAnglePulse, MaxAnglePulse, AngleRange, Frequency)]

Servos.py

@@ -0,0 +1,79 @@
+"""
+Instrument wrapper for PSLab python API
+"""
+
+from time import sleep
+
+from enum import Enum
+
+from OpenTap import Display
+from OpenTap import Unit
+from opentap import *
+
+from .ConnectionHandler import ConnectionHandler
+
+SquareWavePin = Enum('SquareWavePin', ['SQ1', 'SQ2', 'SQ3', 'SQ4'])
+
+@attribute(Display("Servo", "Servo Instrument", "PSLab"))
+class Servos(Instrument):
+    min_angle_pulse = property(float, 500)\
+        .add_attribute(Unit("ms"))\
+        .add_attribute(Display("Min. Angle Pulse", "Pulse length corresponding to the minimum (usually 0 degree) angle of the servo.", "", -50))
+
+    max_angle_pulse = property(float, 2500)\
+        .add_attribute(Unit("ms"))\
+        .add_attribute(Display("Max. Angle Pulse", "Pulse length corresponding to the maximum (usually 180 degree) angle of the servo.", "", -40))
+
+    angle_range = property(float, 180)\
+        .add_attribute(Unit("°"))\
+        .add_attribute(Display("Angle Range", "Range of the servo.", "", -30))
+
+    frequency = property(float, 50)\
+        .add_attribute(Unit("Hz"))\
+        .add_attribute(Display("Frequency", "Frequency of the control signal.", "", -20))
+
+    def __init__(self):
+        """Set up the properties, methods and default values of the instrument."""
+        super(Servos, self).__init__()  # The base class initializer must be invoked.
+        self.instrument = None
+        self.Name = "Servo"
+        self.Rules.Add(Rule("min_angle_pulse", lambda: self.min_angle_pulse > 0, lambda: 'Angle pulse must be positive.'))
+        self.Rules.Add(Rule("max_angle_pulse", lambda: self.max_angle_pulse > 0, lambda: 'Angle pulse must be positive.'))
+        self.Rules.Add(Rule("angle_range", lambda: self.angle_range > 0, lambda: 'Angle range must be positive.'))
+        self.Rules.Add(Rule("angle_range", lambda: self.angle_range <= 360, lambda: 'Angle range must not exceed 360°.'))
+        self.Rules.Add(Rule("frequency", lambda: self.frequency > 0, lambda: 'Frequency must be positive.'))
+
+    def Open(self):
+        super(Servos, self).Open()
+        # Open COM connection to instrument using ConnectionHandler
+        self.instrument = ConnectionHandler.instance().getServos(self.min_angle_pulse, self.max_angle_pulse, self.angle_range, self.frequency)
+        """Called by TAP when the test plan starts"""
+
+    def Close(self):
+        """Called by TAP when the test plan ends."""
+        super(Servos, self).Close()
+
+    def get_min_angle(self):
+            return 0
+
+    def get_max_angle(self):
+            return self.angle_range
+
+    def _get_servo(self, pin: SquareWavePin):
+        match pin:
+            case SquareWavePin.SQ1:
+                return self.instrument[0]
+            case SquareWavePin.SQ2:
+                return self.instrument[1]
+            case SquareWavePin.SQ3:
+                return self.instrument[2]
+            case SquareWavePin.SQ4:
+                return self.instrument[3]
+            case _:
+                raise Exception("Unsupported pin " + pin)
+
+    def set_angle(self, pin: SquareWavePin, angle: int):
+        """ Wait a few milliseconds to allow the command to be processed between steps.
+        Otherwise, movements could be omitted if the commands are sent too quickly one after the other. """
+        sleep(20/1000)
+        self._get_servo(pin).angle = angle

SetServoAngleStep.py

@@ -0,0 +1,37 @@
+"""
+Test step to set the angle of a connected servo on a SQ1-4 pin
+"""
+
+from OpenTap import Display, Unit, Verdict
+from System import Double
+from opentap import *
+
+from .Servos import *
+
+
+@attribute(Display("Set Servo Angle", "Sets angle of a connected servo", Groups=["PSLab", "Servo"]))
+class SetServoAngleStep(TestStep):
+    # Properties
+    pin = property(SquareWavePin, SquareWavePin.SQ1) \
+        .add_attribute(Display("Pin", "Pin on which the square wave is generated", "", -50))
+
+    angle = property(float, 0) \
+        .add_attribute(Display("Angle", "The angle to be set on a chosen SQ pin", "", -40)) \
+        .add_attribute(Unit("°"))
+
+    Servos = property(Servos, None) \
+        .add_attribute(Display("Servo", "", "Resources", 0))
+
+    def __init__(self):
+        super(SetServoAngleStep, self).__init__()
+
+        self.Rules.Add(
+            Rule("angle", lambda: self.angle >= self.Servos.get_min_angle(),
+                 lambda: f'Angle must be at least {self.Servos.get_min_angle()}°.'))
+        self.Rules.Add(
+            Rule("angle", lambda: self.angle <= self.Servos.get_max_angle(),
+                 lambda: f'Angle must not exceed {self.Servos.get_max_angle()}°.'))
+
+    def Run(self):
+        self.Servos.set_angle(self.pin, self.angle)
+        self.UpgradeVerdict(Verdict.Pass)