diff --git a/homeassistant/components/modbus/__init__.py b/homeassistant/components/modbus/__init__.py
index 5f3ddd7a4b5..875669e6dd7 100644
--- a/homeassistant/components/modbus/__init__.py
+++ b/homeassistant/components/modbus/__init__.py
@@ -312,7 +312,7 @@ SENSOR_SCHEMA = vol.All(
             vol.Optional(CONF_STATE_CLASS): SENSOR_STATE_CLASSES_SCHEMA,
             vol.Optional(CONF_UNIT_OF_MEASUREMENT): cv.string,
             vol.Exclusive(CONF_VIRTUAL_COUNT, "vir_sen_count"): cv.positive_int,
-            vol.Optional(CONF_SLAVE_COUNT, "vir_sen_count"): cv.positive_int,
+            vol.Exclusive(CONF_SLAVE_COUNT, "vir_sen_count"): cv.positive_int,
             vol.Optional(CONF_MIN_VALUE): number_validator,
             vol.Optional(CONF_MAX_VALUE): number_validator,
             vol.Optional(CONF_NAN_VALUE): nan_validator,
diff --git a/tests/components/modbus/conftest.py b/tests/components/modbus/conftest.py
index d4c7dfa5e10..a08743b7e6c 100644
--- a/tests/components/modbus/conftest.py
+++ b/tests/components/modbus/conftest.py
@@ -10,7 +10,7 @@ from pymodbus.exceptions import ModbusException
 import pytest
 
 from homeassistant.components.modbus.const import MODBUS_DOMAIN as DOMAIN, TCP
-from homeassistant.const import CONF_HOST, CONF_NAME, CONF_PORT, CONF_SLAVE, CONF_TYPE
+from homeassistant.const import CONF_HOST, CONF_NAME, CONF_PORT, CONF_TYPE
 from homeassistant.core import HomeAssistant
 from homeassistant.setup import async_setup_component
 import homeassistant.util.dt as dt_util
@@ -87,9 +87,6 @@ async def mock_modbus_fixture(
     for key in conf:
         if config_addon:
             conf[key][0].update(config_addon)
-        for entity in conf[key]:
-            if CONF_SLAVE not in entity:
-                entity[CONF_SLAVE] = 0
     caplog.set_level(logging.WARNING)
     config = {
         DOMAIN: [
diff --git a/tests/components/modbus/test_binary_sensor.py b/tests/components/modbus/test_binary_sensor.py
index 7f668b26e04..2069aa23b8f 100644
--- a/tests/components/modbus/test_binary_sensor.py
+++ b/tests/components/modbus/test_binary_sensor.py
@@ -8,6 +8,7 @@ from homeassistant.components.modbus.const import (
     CALL_TYPE_DISCRETE,
     CALL_TYPE_REGISTER_HOLDING,
     CALL_TYPE_REGISTER_INPUT,
+    CONF_DEVICE_ADDRESS,
     CONF_INPUT_TYPE,
     CONF_LAZY_ERROR,
     CONF_SLAVE_COUNT,
@@ -60,6 +61,18 @@ SLAVE_UNIQUE_ID = "ground_floor_sensor"
                 }
             ]
         },
+        {
+            CONF_BINARY_SENSORS: [
+                {
+                    CONF_NAME: TEST_ENTITY_NAME,
+                    CONF_ADDRESS: 51,
+                    CONF_DEVICE_ADDRESS: 10,
+                    CONF_INPUT_TYPE: CALL_TYPE_DISCRETE,
+                    CONF_DEVICE_CLASS: "door",
+                    CONF_LAZY_ERROR: 10,
+                }
+            ]
+        },
         {
             CONF_BINARY_SENSORS: [
                 {
@@ -70,6 +83,16 @@ SLAVE_UNIQUE_ID = "ground_floor_sensor"
                 }
             ]
         },
+        {
+            CONF_BINARY_SENSORS: [
+                {
+                    CONF_NAME: TEST_ENTITY_NAME,
+                    CONF_ADDRESS: 51,
+                    CONF_DEVICE_ADDRESS: 10,
+                    CONF_INPUT_TYPE: CALL_TYPE_REGISTER_INPUT,
+                }
+            ]
+        },
     ],
 )
 async def test_config_binary_sensor(hass: HomeAssistant, mock_modbus) -> None:
@@ -299,7 +322,7 @@ TEST_NAME = "test_sensor"
             CONF_BINARY_SENSORS: [
                 {
                     CONF_NAME: TEST_ENTITY_NAME,
-                    CONF_ADDRESS: 51,
+                    CONF_ADDRESS: 52,
                     CONF_VIRTUAL_COUNT: 3,
                 }
             ]
diff --git a/tests/components/modbus/test_climate.py b/tests/components/modbus/test_climate.py
index 4ab78df0c81..f2de0177c74 100644
--- a/tests/components/modbus/test_climate.py
+++ b/tests/components/modbus/test_climate.py
@@ -11,6 +11,7 @@ from homeassistant.components.climate.const import (
 from homeassistant.components.modbus.const import (
     CONF_CLIMATES,
     CONF_DATA_TYPE,
+    CONF_DEVICE_ADDRESS,
     CONF_HVAC_MODE_AUTO,
     CONF_HVAC_MODE_COOL,
     CONF_HVAC_MODE_DRY,
@@ -57,6 +58,16 @@ ENTITY_ID = f"{CLIMATE_DOMAIN}.{TEST_ENTITY_NAME}".replace(" ", "_")
                 }
             ],
         },
+        {
+            CONF_CLIMATES: [
+                {
+                    CONF_NAME: TEST_ENTITY_NAME,
+                    CONF_TARGET_TEMP: 117,
+                    CONF_ADDRESS: 117,
+                    CONF_DEVICE_ADDRESS: 10,
+                }
+            ],
+        },
         {
             CONF_CLIMATES: [
                 {
diff --git a/tests/components/modbus/test_cover.py b/tests/components/modbus/test_cover.py
index 66e4537d67e..b91b38b1f70 100644
--- a/tests/components/modbus/test_cover.py
+++ b/tests/components/modbus/test_cover.py
@@ -7,6 +7,7 @@ from homeassistant.components.cover import DOMAIN as COVER_DOMAIN
 from homeassistant.components.modbus.const import (
     CALL_TYPE_COIL,
     CALL_TYPE_REGISTER_HOLDING,
+    CONF_DEVICE_ADDRESS,
     CONF_INPUT_TYPE,
     CONF_LAZY_ERROR,
     CONF_STATE_CLOSED,
@@ -62,6 +63,18 @@ ENTITY_ID2 = f"{ENTITY_ID}_2"
                 }
             ]
         },
+        {
+            CONF_COVERS: [
+                {
+                    CONF_NAME: TEST_ENTITY_NAME,
+                    CONF_ADDRESS: 1234,
+                    CONF_INPUT_TYPE: CALL_TYPE_REGISTER_HOLDING,
+                    CONF_DEVICE_ADDRESS: 10,
+                    CONF_SCAN_INTERVAL: 20,
+                    CONF_LAZY_ERROR: 10,
+                }
+            ]
+        },
     ],
 )
 async def test_config_cover(hass: HomeAssistant, mock_modbus) -> None:
diff --git a/tests/components/modbus/test_fan.py b/tests/components/modbus/test_fan.py
index 2d2cc83162d..e47ed5c2371 100644
--- a/tests/components/modbus/test_fan.py
+++ b/tests/components/modbus/test_fan.py
@@ -8,6 +8,7 @@ from homeassistant.components.modbus.const import (
     CALL_TYPE_DISCRETE,
     CALL_TYPE_REGISTER_HOLDING,
     CALL_TYPE_REGISTER_INPUT,
+    CONF_DEVICE_ADDRESS,
     CONF_FANS,
     CONF_INPUT_TYPE,
     CONF_LAZY_ERROR,
@@ -75,6 +76,24 @@ ENTITY_ID2 = f"{ENTITY_ID}_2"
                 }
             ]
         },
+        {
+            CONF_FANS: [
+                {
+                    CONF_NAME: TEST_ENTITY_NAME,
+                    CONF_ADDRESS: 1234,
+                    CONF_DEVICE_ADDRESS: 1,
+                    CONF_COMMAND_OFF: 0x00,
+                    CONF_COMMAND_ON: 0x01,
+                    CONF_LAZY_ERROR: 10,
+                    CONF_VERIFY: {
+                        CONF_INPUT_TYPE: CALL_TYPE_REGISTER_HOLDING,
+                        CONF_ADDRESS: 1235,
+                        CONF_STATE_OFF: 0,
+                        CONF_STATE_ON: 1,
+                    },
+                }
+            ]
+        },
         {
             CONF_FANS: [
                 {
diff --git a/tests/components/modbus/test_init.py b/tests/components/modbus/test_init.py
index a68ac2d3738..f9c7fb42b2d 100644
--- a/tests/components/modbus/test_init.py
+++ b/tests/components/modbus/test_init.py
@@ -41,6 +41,7 @@ from homeassistant.components.modbus.const import (
     CONF_BAUDRATE,
     CONF_BYTESIZE,
     CONF_DATA_TYPE,
+    CONF_DEVICE_ADDRESS,
     CONF_INPUT_TYPE,
     CONF_MSG_WAIT,
     CONF_PARITY,
@@ -517,6 +518,20 @@ async def test_duplicate_entity_validator(do_config) -> None:
                 }
             ],
         },
+        {
+            # Special test for scan_interval validator with scan_interval: 0
+            CONF_TYPE: TCP,
+            CONF_HOST: TEST_MODBUS_HOST,
+            CONF_PORT: TEST_PORT_TCP,
+            CONF_SENSORS: [
+                {
+                    CONF_NAME: TEST_ENTITY_NAME,
+                    CONF_ADDRESS: 117,
+                    CONF_DEVICE_ADDRESS: 0,
+                    CONF_SCAN_INTERVAL: 0,
+                }
+            ],
+        },
     ],
 )
 async def test_config_modbus(
diff --git a/tests/components/modbus/test_light.py b/tests/components/modbus/test_light.py
index 46763b3b3a2..a5871bdbd67 100644
--- a/tests/components/modbus/test_light.py
+++ b/tests/components/modbus/test_light.py
@@ -8,6 +8,7 @@ from homeassistant.components.modbus.const import (
     CALL_TYPE_DISCRETE,
     CALL_TYPE_REGISTER_HOLDING,
     CALL_TYPE_REGISTER_INPUT,
+    CONF_DEVICE_ADDRESS,
     CONF_INPUT_TYPE,
     CONF_LAZY_ERROR,
     CONF_STATE_OFF,
@@ -75,6 +76,23 @@ ENTITY_ID2 = f"{ENTITY_ID}_2"
                 }
             ]
         },
+        {
+            CONF_LIGHTS: [
+                {
+                    CONF_NAME: TEST_ENTITY_NAME,
+                    CONF_ADDRESS: 1234,
+                    CONF_DEVICE_ADDRESS: 1,
+                    CONF_COMMAND_OFF: 0x00,
+                    CONF_COMMAND_ON: 0x01,
+                    CONF_VERIFY: {
+                        CONF_INPUT_TYPE: CALL_TYPE_REGISTER_HOLDING,
+                        CONF_ADDRESS: 1235,
+                        CONF_STATE_OFF: 0,
+                        CONF_STATE_ON: 1,
+                    },
+                }
+            ]
+        },
         {
             CONF_LIGHTS: [
                 {
diff --git a/tests/components/modbus/test_sensor.py b/tests/components/modbus/test_sensor.py
index 0833c0e2f7f..46c38873a93 100644
--- a/tests/components/modbus/test_sensor.py
+++ b/tests/components/modbus/test_sensor.py
@@ -8,6 +8,7 @@ from homeassistant.components.modbus.const import (
     CALL_TYPE_REGISTER_HOLDING,
     CALL_TYPE_REGISTER_INPUT,
     CONF_DATA_TYPE,
+    CONF_DEVICE_ADDRESS,
     CONF_INPUT_TYPE,
     CONF_LAZY_ERROR,
     CONF_MAX_VALUE,
@@ -86,6 +87,23 @@ SLAVE_UNIQUE_ID = "ground_floor_sensor"
                 }
             ]
         },
+        {
+            CONF_SENSORS: [
+                {
+                    CONF_NAME: TEST_ENTITY_NAME,
+                    CONF_ADDRESS: 51,
+                    CONF_DEVICE_ADDRESS: 10,
+                    CONF_DATA_TYPE: DataType.INT16,
+                    CONF_PRECISION: 0,
+                    CONF_SCALE: 1,
+                    CONF_OFFSET: 0,
+                    CONF_STATE_CLASS: SensorStateClass.MEASUREMENT,
+                    CONF_LAZY_ERROR: 10,
+                    CONF_INPUT_TYPE: CALL_TYPE_REGISTER_HOLDING,
+                    CONF_DEVICE_CLASS: "battery",
+                }
+            ]
+        },
         {
             CONF_SENSORS: [
                 {
diff --git a/tests/components/modbus/test_switch.py b/tests/components/modbus/test_switch.py
index 7a79e19869a..ff7d6860f3b 100644
--- a/tests/components/modbus/test_switch.py
+++ b/tests/components/modbus/test_switch.py
@@ -11,6 +11,7 @@ from homeassistant.components.modbus.const import (
     CALL_TYPE_DISCRETE,
     CALL_TYPE_REGISTER_HOLDING,
     CALL_TYPE_REGISTER_INPUT,
+    CONF_DEVICE_ADDRESS,
     CONF_INPUT_TYPE,
     CONF_LAZY_ERROR,
     CONF_STATE_OFF,
@@ -85,6 +86,24 @@ ENTITY_ID2 = f"{ENTITY_ID}_2"
                 }
             ]
         },
+        {
+            CONF_SWITCHES: [
+                {
+                    CONF_NAME: TEST_ENTITY_NAME,
+                    CONF_ADDRESS: 1234,
+                    CONF_DEVICE_ADDRESS: 1,
+                    CONF_COMMAND_OFF: 0x00,
+                    CONF_COMMAND_ON: 0x01,
+                    CONF_DEVICE_CLASS: "switch",
+                    CONF_VERIFY: {
+                        CONF_INPUT_TYPE: CALL_TYPE_REGISTER_HOLDING,
+                        CONF_ADDRESS: 1235,
+                        CONF_STATE_OFF: 0,
+                        CONF_STATE_ON: 1,
+                    },
+                }
+            ]
+        },
         {
             CONF_SWITCHES: [
                 {