Fix decoding of current values

Current sensors are encoded as both signed and unsigned values.
Former Current sensor is now U16, new CurrentS is for S16 values.

goodwe/et.py

@@ -115,7 +115,7 @@ class ET(Inverter):
         Voltage("bus_voltage", 35178, "Bus Voltage", None),
         Voltage("nbus_voltage", 35179, "NBus Voltage", None),
         Voltage("vbattery1", 35180, "Battery Voltage", Kind.BAT),
-        Current("ibattery1", 35181, "Battery Current", Kind.BAT),
+        CurrentS("ibattery1", 35181, "Battery Current", Kind.BAT),
         Power4("pbattery1", 35182, "Battery Power", Kind.BAT),
         Integer("battery_mode", 35184, "Battery Mode code", "", Kind.BAT),
         Enum2("battery_mode_label", 35184, BATTERY_MODES, "Battery Mode", Kind.BAT),

goodwe/sensor.py

@@ -83,7 +83,7 @@ def is_in_range(self, value: int) -> bool:
 
 
 class Voltage(Sensor):
-    """Sensor representing voltage [V] value encoded in 2 bytes"""
+    """Sensor representing voltage [V] value encoded in 2 (unsigned) bytes"""
 
     def __init__(self, id_: str, offset: int, name: str, kind: Optional[SensorKind]):
         super().__init__(id_, offset, name, 2, "V", kind)
@@ -96,7 +96,7 @@ def encode_value(self, value: Any, register_value: bytes = None) -> bytes:
 
 
 class Current(Sensor):
-    """Sensor representing current [A] value encoded in 2 bytes"""
+    """Sensor representing current [A] value encoded in 2 (unsigned) bytes"""
 
     def __init__(self, id_: str, offset: int, name: str, kind: Optional[SensorKind]):
         super().__init__(id_, offset, name, 2, "A", kind)
@@ -108,6 +108,19 @@ def encode_value(self, value: Any, register_value: bytes = None) -> bytes:
         return encode_current(value)
 
 
+class CurrentS(Sensor):
+    """Sensor representing current [A] value encoded in 2 (signed) bytes"""
+
+    def __init__(self, id_: str, offset: int, name: str, kind: Optional[SensorKind]):
+        super().__init__(id_, offset, name, 2, "A", kind)
+
+    def read_value(self, data: ProtocolResponse):
+        return read_current_signed(data)
+
+    def encode_value(self, value: Any, register_value: bytes = None) -> bytes:
+        return encode_current_signed(value)
+
+
 class Frequency(Sensor):
     """Sensor representing frequency [Hz] value encoded in 2 bytes"""
 
@@ -736,28 +749,41 @@ def read_float4(buffer: ProtocolResponse, offset: int = None) -> float:
 
 
 def read_voltage(buffer: ProtocolResponse, offset: int = None) -> float:
-    """Retrieve voltage [V] value (2 bytes) from buffer"""
+    """Retrieve voltage [V] value (2 unsigned bytes) from buffer"""
     if offset is not None:
         buffer.seek(offset)
     value = int.from_bytes(buffer.read(2), byteorder="big", signed=False)
     return float(value) / 10 if value != 0xffff else 0
 
 
 def encode_voltage(value: Any) -> bytes:
-    """Encode voltage value to raw (2 bytes) payload"""
+    """Encode voltage value to raw (2 unsigned bytes) payload"""
     return int.to_bytes(int(value * 10), length=2, byteorder="big", signed=False)
 
 
 def read_current(buffer: ProtocolResponse, offset: int = None) -> float:
-    """Retrieve current [A] value (2 bytes) from buffer"""
+    """Retrieve current [A] value (2 unsigned bytes) from buffer"""
+    if offset is not None:
+        buffer.seek(offset)
+    value = int.from_bytes(buffer.read(2), byteorder="big", signed=False)
+    return float(value) / 10
+
+
+def read_current_signed(buffer: ProtocolResponse, offset: int = None) -> float:
+    """Retrieve current [A] value (2 signed bytes) from buffer"""
     if offset is not None:
         buffer.seek(offset)
     value = int.from_bytes(buffer.read(2), byteorder="big", signed=True)
     return float(value) / 10
 
 
 def encode_current(value: Any) -> bytes:
-    """Encode current value to raw (2 bytes) payload"""
+    """Encode current value to raw (2 unsigned bytes) payload"""
+    return int.to_bytes(int(value * 10), length=2, byteorder="big", signed=False)
+
+
+def encode_current_signed(value: Any) -> bytes:
+    """Encode current value to raw (2 signed bytes) payload"""
     return int.to_bytes(int(value * 10), length=2, byteorder="big", signed=True)
 
 

tests/test_sensor.py

@@ -78,13 +78,30 @@ def test_voltage(self):
         self.assertEqual(803.6, testee.read(data))
         self.assertEqual("1f64", testee.encode_value(803.6).hex())
 
+        data = MockResponse("a000")
+        self.assertEqual(4096.0, testee.read(data))
+
+        data = MockResponse("ffff")
+        self.assertEqual(0, testee.read(data))
+
     def test_current(self):
         testee = Current("", 0, "", None)
 
         data = MockResponse("0031")
         self.assertEqual(4.9, testee.read(data))
         self.assertEqual("0031", testee.encode_value(4.9).hex())
 
+        data = MockResponse("ff9e")
+        self.assertEqual(6543.8, testee.read(data))
+        self.assertEqual("ff9e", testee.encode_value(6543.8).hex())
+
+    def test_current_signed(self):
+        testee = CurrentS("", 0, "", None)
+
+        data = MockResponse("0031")
+        self.assertEqual(4.9, testee.read(data))
+        self.assertEqual("0031", testee.encode_value(4.9).hex())
+
         data = MockResponse("ff9e")
         self.assertEqual(-9.8, testee.read(data))
         self.assertEqual("ff9e", testee.encode_value(-9.8).hex())