diff --git a/controllers/modbus.controller.js b/controllers/modbus.controller.js
index 8dbe8b8..d4d1e89 100644
--- a/controllers/modbus.controller.js
+++ b/controllers/modbus.controller.js
@@ -3,6 +3,7 @@ import modbusClient from "#root/config/modbus-client.config.js";
 import * as utils from '#root/utils/index.js'
 import { RowNotFoundError } from '#root/errors/index.js'
 import { appService, modbusService } from "#root/services/index.js";
+import { modbusDeviceModel } from "#root/models/index.js";
 
 export const modbusController = {
   /**
@@ -222,11 +223,9 @@ export const modbusController = {
   async streamData(req, res, next) {
     try {
       const { slave_id } = req.query;
-
-      if (!modbusClient.isOpen) return res.status(503).json({ error: { message: "Modbus connection closed." } });
       if (!slave_id) return res.status(400).json({ error: { message: "'slave_id' parameter is required." } });
 
-      const device = await db.get(`SELECT * FROM "modbus_slaves" WHERE id = ?`, [slave_id]);
+      const device = await modbusDeviceModel.getById(slave_id.toString());
       if (!device) throw new RowNotFoundError();
 
       utils.setSSEHeaders(res);
@@ -235,7 +234,7 @@ export const modbusController = {
         device,
         (data, error) => {
           if (error) {
-            next(error);
+            res.write(utils.serializeSSEData({ error: { message: error.message }}, 'message'))
             return;
           }
           res.write(utils.serializeSSEData(data, 'message'));
diff --git a/data.db b/data.db
index e7d0fa1..45ad0ee 100644
Binary files a/data.db and b/data.db differ
diff --git a/models/index.js b/models/index.js
new file mode 100644
index 0000000..e024dba
--- /dev/null
+++ b/models/index.js
@@ -0,0 +1,79 @@
+import db from '#root/config/database.config.js'
+
+class BaseModel {
+  /**
+   * @param {string} table 
+   */
+  constructor(table) {
+    this.table = table;
+  }
+
+  /**
+   * @param {number | string} id
+   * @param {string[]} keys
+   * @return {Promise<any>}
+   */
+  async getById(id, keys = ['*']) {
+    const query = `SELECT ${keys.join(',')} FROM ${this.table} WHERE id = ?`;
+    const params = [id];
+    const res = await db.get(query, params);
+    return res;
+  }
+
+  /**
+   * @param {number | string} id
+   * @return {Promise<void>}
+   */
+  async delById(id) {
+    const query = `DELETE FROM ${this.table} WHERE id = ?`;
+    await db.run(query, [id]);
+  }
+
+  async getList(keys = ['*']) {
+    const query = `SELECT ${keys.join(',')} FROM ${this.table}`;
+    const res = await db.all(query);
+    return res;
+  }
+
+  async create(fields, values) {
+    const query = `
+      INSERT INTO ${this.table} 
+        (${fields.join(',')}) 
+        VALUES (${values.map(() => '?').join(',')})`;
+    await db.run(query, values);
+    return this;
+  }
+}
+
+class ModbusDeviceModel extends BaseModel {
+  constructor(table) {
+    super(table);
+  }
+
+  /**
+   * @return {Promise<import('..').ModbusDevice[]>}
+   */
+  async getListWithDisplayValues() {
+    const query = `
+      SELECT  ms.id AS id, ms.name AS name, g_display_reg_addr, g_display_reg_format, g_display_reg_type, g_y_label,
+        CASE
+          WHEN COUNT(dv.id) = 0 THEN '[]'
+          ELSE '[' || GROUP_CONCAT(
+            JSON_OBJECT(
+              'id', dv.id,
+              'name', dv.name,
+              'reg_addr', dv.reg_addr,
+              'reg_format', dv.reg_format,
+              'reg_type', dv.reg_type
+            ), ', '
+          ) || ']' END AS display_values
+        FROM ${this.table} AS ms
+        LEFT JOIN display_values AS dv ON dv.slave_id = ms.id
+        GROUP BY ms.id, ms.name;`;
+    const devices = await db.all(query);
+    devices.forEach((s) => (s.display_values = JSON.parse(s.display_values)));
+    return devices;
+  }
+}
+
+export const modbusDeviceModel = new ModbusDeviceModel('modbus_slaves');
\ No newline at end of file
diff --git a/public/js/app.js b/public/js/app.js
index 0fa8e70..f62a3a4 100644
--- a/public/js/app.js
+++ b/public/js/app.js
@@ -272,13 +272,18 @@ document.addEventListener("alpine:init", async () => {
 
       dataStreamSource?.close();
       dataStreamSource = new EventSource(`/api/modbus/data_stream?slave_id=${device.id}`);
-      dataStreamSource.onerror = (e) => {
-        dataStreamSource.close();
-        this.isLoading = false;
-        this.error = { message: "Something went wrong." };
-      };
       dataStreamSource.onmessage = (e) => {
         const data = JSON.parse(e.data);
+
+        if (data.error) {
+          this.isLoading = false;
+          this.error = data.error;
+          console.error('[Modbus Error]:', data.error);
+          return;
+        }
+
+        this.error = null;
+
         console.log("[SSE Message]", data);
         if (data.graph !== null) {
           this.selectedDevice.g_value = data.graph.value;
diff --git a/services/modbus.service.js b/services/modbus.service.js
index 6a9fd45..28e6d4d 100644
--- a/services/modbus.service.js
+++ b/services/modbus.service.js
@@ -1,6 +1,7 @@
 import modbusClient from "#root/config/modbus-client.config.js";
 import db from "#root/config/database.config.js";
 import * as utils from "#root/utils/index.js";
+import { modbusDeviceModel } from "#root/models/index.js";
 
 export const modbusService = {
   /**
@@ -121,26 +122,7 @@ export const modbusService = {
   },
 
   async getDevices() {
-    /** @type {import("..").ModbusDevice[]}  */
-    const devices = await db.all(`
-        SELECT  ms.id AS id, ms.name AS name, g_display_reg_addr, g_display_reg_format, g_display_reg_type, g_y_label,
-        CASE
-          WHEN COUNT(dv.id) = 0 THEN '[]'
-          ELSE '[' || GROUP_CONCAT(
-            JSON_OBJECT(
-              'id', dv.id,
-              'name', dv.name,
-              'reg_addr', dv.reg_addr,
-              'reg_format', dv.reg_format,
-              'reg_type', dv.reg_type
-            ), ', '
-          ) || ']' END AS display_values
-        FROM modbus_slaves AS ms
-        LEFT JOIN display_values AS dv ON dv.slave_id = ms.id
-        GROUP BY ms.id, ms.name;
-    `);
-    // @ts-ignore
-    devices.forEach((s) => (s.display_values = JSON.parse(s.display_values)));
+    const devices = modbusDeviceModel.getListWithDisplayValues();
     return devices;
   },