#41: New feature register write

sun2000_modbus/datatypes.py

@@ -2,32 +2,57 @@
 
 
 class DataType(Enum):
-    STRING = "string"
-    UINT16_BE = "uint16"
-    UINT32_BE = "uint32"
-    INT16_BE = "int16"
-    INT32_BE = "int32"
-    BITFIELD16 = "bitfield16"
-    BITFIELD32 = "bitfield32"
-    MULTIDATA = "multidata"
+    STRING = 'string'
+    UINT16_BE = 'uint16'
+    UINT32_BE = 'uint32'
+    INT16_BE = 'int16'
+    INT32_BE = 'int32'
+    BITFIELD16 = 'bitfield16'
+    BITFIELD32 = 'bitfield32'
+    MULTIDATA = 'multidata'
 
 
 def decode_string(value):
-    return value.decode("utf-8", "replace").strip("\0")
+    return value.decode('utf-8', 'replace').strip('\0')
+
+
+def encode_uint_be(value, length):
+    return int.to_bytes(value, length=length, byteorder='big', signed=False)
 
 
 def decode_uint_be(value):
-    return int.from_bytes(value, byteorder="big", signed=False)
+    return int.from_bytes(value, byteorder='big', signed=False)
+
+
+def encode_int_be(value, length):
+    return int.to_bytes(value, length=length, byteorder='big', signed=True)
 
 
 def decode_int_be(value):
-    return int.from_bytes(value, byteorder="big", signed=True)
+    return int.from_bytes(value, byteorder='big', signed=True)
 
 
 def decode_bitfield(value):
     return ''.join(format(byte, '08b') for byte in value)
 
 
+def encode(value, data_type):
+    if data_type == DataType.UINT16_BE:
+        return encode_uint_be(value, 2)
+    elif data_type == DataType.UINT32_BE:
+        return encode_uint_be(value, 4)
+    elif data_type == DataType.INT16_BE:
+        return encode_int_be(value, 2)
+    elif data_type == DataType.INT32_BE:
+        return encode_int_be(value, 4)
+    elif data_type == DataType.MULTIDATA:
+        if len(value) % 2 != 0:
+            raise ValueError('Multidata value length must be a multiple of 2')
+        return value
+    else:
+        raise ValueError('Writing is not supported for register type')
+
+
 def decode(value, data_type):
     if data_type == DataType.STRING:
         return decode_string(value)
@@ -40,4 +65,4 @@ def decode(value, data_type):
     elif data_type == DataType.MULTIDATA:
         return value
     else:
-        raise ValueError("Unknown register type")
+        raise ValueError('Unknown register type')

sun2000_modbus/inverter.py

@@ -5,6 +5,7 @@
 from pymodbus.exceptions import ModbusIOException, ConnectionException
 
 from . import datatypes
+from .registers import AccessType
 
 logger = logging.getLogger(__name__)
 logger.setLevel(logging.INFO)
@@ -35,8 +36,8 @@ def connect(self):
     def disconnect(self):
         """Close the underlying tcp socket"""
         # Some Sun2000 models with the SDongle WLAN-FE require the TCP connection to be closed
-        # as soon as possible. Leaving the TCP connection open for an extended time may cause 
-        # dongle reboots and/or FusionSolar portal updates to be delayed or even paused. 
+        # as soon as possible. Leaving the TCP connection open for an extended time may cause
+        # dongle reboots and/or FusionSolar portal updates to be delayed or even paused.
         self.inverter.close()
 
     def isConnected(self):
@@ -54,10 +55,10 @@ def read_raw_value(self, register):
         try:
             register_value = self.inverter.read_holding_registers(register.value.address, register.value.quantity, slave=self.slave)
             if type(register_value) == ModbusIOException:
-                logger.error("Inverter unit did not respond")
+                logger.error('Inverter unit did not respond')
                 raise register_value
         except ConnectionException:
-            logger.error("A connection error occurred")
+            logger.error('A connection error occurred')
             raise
 
         return datatypes.decode(register_value.encode()[1:], register.value.data_type)
@@ -85,11 +86,11 @@ def read_formatted(self, register, use_locale=False):
 
     def read_range(self, start_address, quantity=0, end_address=0):
         if quantity == 0 and end_address == 0:
-            raise ValueError("Either parameter quantity or end_address is required and must be greater than 0")
+            raise ValueError('Either parameter quantity or end_address is required and must be greater than 0')
         if quantity != 0 and end_address != 0:
-            raise ValueError("Only one parameter quantity or end_address should be defined")
+            raise ValueError('Only one parameter quantity or end_address should be defined')
         if end_address != 0 and end_address <= start_address:
-            raise ValueError("end_address must be greater than start_address")
+            raise ValueError('end_address must be greater than start_address')
 
         if not self.isConnected():
             raise ValueError('Inverter is not connected')
@@ -99,10 +100,28 @@ def read_range(self, start_address, quantity=0, end_address=0):
         try:
             register_range_value = self.inverter.read_holding_registers(start_address, quantity, slave=self.slave)
             if type(register_range_value) == ModbusIOException:
-                logger.error("Inverter unit did not respond")
+                logger.error('Inverter unit did not respond')
                 raise register_range_value
         except ConnectionException:
-            logger.error("A connection error occurred")
+            logger.error('A connection error occurred')
             raise
 
         return datatypes.decode(register_range_value.encode()[1:], datatypes.DataType.MULTIDATA)
+
+    def write(self, register, value):
+        if not self.isConnected():
+            raise ValueError('Inverter is not connected')
+        if not register.value.access_type in [AccessType.RW, AccessType.WO]:
+            raise ValueError('Register is not writeable')
+
+        encoded_value = datatypes.encode(value, register.value.data_type)
+        chunks = [encoded_value[i:i+2] for i in range(0, len(encoded_value), 2)]
+
+        try:
+            response = self.inverter.write_registers(register.value.address, chunks, slave=self.slave, skip_encode=True)
+            if type(response) == ModbusIOException:
+                logger.error('Inverter unit did not respond')
+                raise response
+        except ConnectionException:
+            logger.error('A connection error occurred')
+            raise