Fixed and extended csv_logging.py

src/psu_device.py

@@ -15,6 +15,7 @@ class PSUDevice(ABC):
         """PSUDevice assumes a serial connection"""
         ui_print("\nConnecting to power supply...")
         self.com_port = com_port
+        self.cached_state = dict.fromkeys(self.valid_channels())  # Used for components that require state on demand
 
     @abstractmethod
     def enable_channel(self, channel_nr):
@@ -53,10 +54,24 @@ class PSUDevice(ABC):
     def poll_channel_state(self, channel_nr):
         """Return a dictionary with the entries below. WARNING: this call is blocking and potentially slow!
         Can throw exceptions"""
+        # Should also set self.cached_state
         # return {'active': False, 'remote_active': False,
         #         'actual_voltage':0, 'limit_voltage':0, 'actual_current':0, 'limit_current':0}
         pass
 
+    def cached_channel_state(self, channel_nr):
+        """Return a dictionary with the entries below. Uses the values obtained during last poll.
+        May contain None-entries"""
+
+        if self.cached_state[channel_nr]:
+            return self.cached_state[channel_nr]
+        else:
+            return {'active': None, 'remote_active': None,
+                    'actual_voltage': None,
+                    'limit_voltage': None,
+                    'actual_current': None,
+                    'limit_current': None}
+
     def idle(self):
         """Zero all outputs but activate channels so commands can be sent."""
         for ch in self.valid_channels():
@@ -130,9 +145,11 @@ class PSUDevicePS2000B(PSUDevice):
         time.sleep(self.MIN_DELAY)
 
         # Format should match the provided template in abstract PSUDevice class.
-        return {'active': dev_status.output_active, 'remote_active': dev_status.remote_control_active,
-                'voltage': voltage, 'voltage_setpoint': voltage_setp,
-                'current': current, 'current_setpoint': current_setp}
+        self.cached_state[channel_nr] = {'active': dev_status.output_active,
+                                         'remote_active': dev_status.remote_control_active,
+                                         'voltage': voltage, 'voltage_setpoint': voltage_setp,
+                                         'current': current, 'current_setpoint': current_setp}
+        return self.cached_state[channel_nr]
 
     def shutdown(self):
         for ch in self.valid_channels():
@@ -161,6 +178,7 @@ class PSUDeviceQL355TP(PSUDevice):
         self.set_output_range(0, 0)  # Put the PSU into the 15V/5A range
         self.set_output_range(1, 0)
         self.reset_breaker()  # Reset the breaker in case we are coming from an unclean state
+        self.cached_state = dict.fromkeys(self.valid_channels())  # Used for components that require state on demand
 
     @staticmethod
     def valid_channels():
@@ -216,9 +234,10 @@ class PSUDeviceQL355TP(PSUDevice):
         # Format should match the provided template in abstract PSUDevice class.
         # The remote_active property is assumed to always be True since it cant be read
         # (it should be since we are talking to it)
-        return {'active': output_active, 'remote_active': True,
-                'voltage': voltage, 'voltage_setpoint': voltage_setp,
-                'current': current, 'current_setpoint': current_setp}
+        self.cached_state[channel_nr] = {'active': output_active, 'remote_active': True,
+                                         'voltage': voltage, 'voltage_setpoint': voltage_setp,
+                                         'current': current, 'current_setpoint': current_setp}
+        return self.cached_state[channel_nr]
 
     def set_output_range(self, channel_nr, value_range):
         """The QL355TP supports various output ranges. We require the 15V/5A mode to achieve the greatest range."""