diff --git a/app/src/modbus_tcp.py b/app/src/modbus_tcp.py
index f6e8245..724b25f 100644
--- a/app/src/modbus_tcp.py
+++ b/app/src/modbus_tcp.py
@@ -77,7 +77,7 @@ class ModbusTcp():
                 logging.debug(f'Inv-conn:{error}')
 
             except OSError as error:
-                if error.errno == 113:
+                if error.errno == 113:  # pragma: no cover
                     logging.debug(f'os-error:{error}')
                 else:
                     logging.info(f'os-error: {error}')
diff --git a/app/tests/test_modbus_tcp.py b/app/tests/test_modbus_tcp.py
index a39c2cd..da065fd 100644
--- a/app/tests/test_modbus_tcp.py
+++ b/app/tests/test_modbus_tcp.py
@@ -146,6 +146,22 @@ def patch_open_timeout():
     with patch.object(asyncio, 'open_connection', new_open) as conn:
         yield conn
 
+@pytest.fixture
+def patch_open_value_error():
+    def new_open(host: str, port: int):
+        raise ValueError
+
+    with patch.object(asyncio, 'open_connection', new_open) as conn:
+        yield conn
+
+@pytest.fixture
+def patch_open_conn_abort():
+    def new_open(host: str, port: int):
+        raise ConnectionAbortedError
+
+    with patch.object(asyncio, 'open_connection', new_open) as conn:
+        yield conn
+
 @pytest.fixture
 def patch_no_mqtt():
     with patch.object(Mqtt, 'publish') as conn:
@@ -190,7 +206,7 @@ async def test_modbus_no_cnf():
     assert Infos.stat['proxy']['Inverter_Cnt'] == 0
 
 @pytest.mark.asyncio
-async def test_modbus_cnf1(config_conn, patch_open_timeout):
+async def test_modbus_timeout(config_conn, patch_open_timeout):
     _ = config_conn
     _ = patch_open_timeout
     assert asyncio.get_running_loop()
@@ -207,6 +223,42 @@ async def test_modbus_cnf1(config_conn, patch_open_timeout):
     await asyncio.sleep(0.01)
     assert Infos.stat['proxy']['Inverter_Cnt'] == 0
 
+@pytest.mark.asyncio
+async def test_modbus_value_err(config_conn, patch_open_value_error):
+    _ = config_conn
+    _ = patch_open_value_error
+    assert asyncio.get_running_loop()
+    Proxy.class_init()
+
+    assert Infos.stat['proxy']['Inverter_Cnt'] == 0
+    loop = asyncio.get_event_loop()
+    ModbusTcp(loop)
+    await asyncio.sleep(0.01)
+    for m in Message:
+        if (m.node_id == 'inv_2'):
+            assert False
+        
+    await asyncio.sleep(0.01)
+    assert Infos.stat['proxy']['Inverter_Cnt'] == 0
+
+@pytest.mark.asyncio
+async def test_modbus_conn_abort(config_conn, patch_open_conn_abort):
+    _ = config_conn
+    _ = patch_open_conn_abort
+    assert asyncio.get_running_loop()
+    Proxy.class_init()
+
+    assert Infos.stat['proxy']['Inverter_Cnt'] == 0
+    loop = asyncio.get_event_loop()
+    ModbusTcp(loop)
+    await asyncio.sleep(0.01)
+    for m in Message:
+        if (m.node_id == 'inv_2'):
+            assert False
+        
+    await asyncio.sleep(0.01)
+    assert Infos.stat['proxy']['Inverter_Cnt'] == 0
+
 @pytest.mark.asyncio
 async def test_modbus_cnf2(config_conn, patch_no_mqtt, patch_open):
     _ = config_conn