diff --git a/app/config_io.py b/app/config_io.py
new file mode 100644
index 0000000..1bb99bb
--- /dev/null
+++ b/app/config_io.py
@@ -0,0 +1,90 @@
+"""配置文件 I/O（Step 4 重构）。
+
+从 pqAutomationApp.PQAutomationApp 中搬迁。每个函数第一行 `self = app`
+以保留原有 `self.xxx` 属性访问不变。
+"""
+
+import json
+import os
+import sys
+
+def get_config_path(app):
+    """获取配置文件的完整路径（兼容打包后的程序）"""
+    self = app
+    import os
+    import sys
+
+    # 判断是否是打包后的程序
+    if getattr(sys, "frozen", False):
+        # 打包后：使用可执行文件所在目录
+        base_path = os.path.dirname(sys.executable)
+    else:
+        # 开发环境：使用项目根目录（app/config_io.py 的上两级 = 工程根）
+        base_path = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+
+    # 构建配置文件路径
+    config_dir = os.path.join(base_path, "settings")
+    config_file = os.path.join(config_dir, "pq_config.json")
+
+    # 确保 settings 目录存在
+    if not os.path.exists(config_dir):
+        os.makedirs(config_dir)
+
+    return config_file
+
+
+def load_pq_config(app):
+    """加载PQ配置（兼容打包后的程序）"""
+    self = app
+    try:
+        # ✅ 使用 self.config_file（已经是动态路径）
+        if os.path.exists(self.config_file):
+            with open(self.config_file, "r", encoding="utf-8") as f:
+                config_dict = json.load(f)
+                self.config.from_dict(config_dict)
+                if hasattr(self, "log_gui"):
+                    self.log_gui.log("✓ 配置文件加载成功")
+        else:
+            if hasattr(self, "log_gui"):
+                self.log_gui.log("⚠️ 配置文件不存在，使用默认配置")
+    except Exception as e:
+        if hasattr(self, "log_gui"):
+            self.log_gui.log(f"⚠️ 加载配置文件失败: {str(e)}，使用默认配置")
+
+
+def save_pq_config(app):
+    """保存PQ配置（兼容打包后的程序）"""
+    self = app
+    try:
+        # 确保目录存在
+        os.makedirs(os.path.dirname(self.config_file), exist_ok=True)
+
+        # 保存配置
+        self.config.save_to_file(self.config_file)
+    except Exception as e:
+        if hasattr(self, "log_gui"):
+            self.log_gui.log(f"保存配置文件失败: {str(e)}")
+
+
+def clear_config_file(app):
+    """清理配置文件（兼容打包后的程序）"""
+    self = app
+    from tkinter import messagebox
+
+    config_file = self.get_config_path()
+
+    try:
+        if os.path.exists(config_file):
+            os.remove(config_file)
+            self.config_cleared = True
+            messagebox.showinfo("提示", "✓ 清理成功")
+            self.log_gui.log("✓ 配置文件清理成功")
+        else:
+            messagebox.showinfo("提示", "配置文件不存在")
+            self.log_gui.log("⚠️ 配置文件不存在")
+
+    except Exception as e:
+        messagebox.showerror("错误", "❌ 清理失败")
+        self.log_gui.log(f"❌ 配置文件清理失败: {str(e)}")
+
+
diff --git a/app/device/__init__.py b/app/device/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/app/device/connection.py b/app/device/connection.py
new file mode 100644
index 0000000..37afac0
--- /dev/null
+++ b/app/device/connection.py
@@ -0,0 +1,210 @@
+"""设备连接（UCD323 / CA410）相关逻辑（Step 4 重构）。
+
+从 pqAutomationApp.PQAutomationApp 中搬迁。每个函数第一行 `self = app`
+以保留原有 `self.xxx` 属性访问不变。
+"""
+
+import threading
+import time
+from tkinter import messagebox
+
+from utils.caSerail import CASerail
+
+def get_available_ucd_ports(app):
+    """获取可用的UCD端口列表"""
+    self = app
+    return self.ucd.search_device()
+
+
+def get_available_com_ports(app):
+    """获取可用的COM端口列表"""
+    self = app
+    try:
+        import serial.tools.list_ports
+
+        ports = serial.tools.list_ports.comports()
+        return [port.device for port in ports]
+    except Exception as e:
+        self.log_gui.log(f"获取COM端口列表出错: {e}")
+        return []
+
+
+def refresh_com_ports(app):
+    """刷新COM端口列表"""
+    self = app
+    available_ports = self.get_available_com_ports()
+    available_list = self.get_available_ucd_ports()
+
+    # 更新UCD列表的下拉框选项
+    ucd_list_current = self.ucd_list_var.get()
+    if ucd_list_current not in available_list:
+        self.ucd_list_var.set(available_list[0] if available_list else "")
+    self.ucd_list_combo.config(values=available_list)
+
+    # 更新CA端口的下拉框选项
+    ca_com_current = self.ca_com_var.get()
+    if ca_com_current not in available_ports:
+        self.ca_com_var.set(
+            available_ports[1]
+            if len(available_ports) > 1
+            else (available_ports[0] if available_ports else "")
+        )
+    self.ca_com_combo.config(values=available_ports)
+
+    # 重置连接状态指示器为灰色
+    if hasattr(self, "ucd_status_indicator"):
+        self.ucd_status_indicator.config(bg="gray")
+    if hasattr(self, "ca_status_indicator"):
+        self.ca_status_indicator.config(bg="gray")
+
+    self.update_config()
+
+
+def check_com_connections(app):
+    """检测COM端口连接状态"""
+    self = app
+    # 禁用连接按钮，防止重复点击
+    self.check_button.configure(state="disabled")
+    self.refresh_button.configure(state="disabled")
+
+    # 更新状态栏
+    self.status_var.set("正在检测连接...")
+    self.root.update()
+
+    # 使用线程进行连接检测
+    def check_connections():
+        try:
+            # 检测TV连接
+            ucd_connected = self.check_port_connection(is_ucd=True)
+            self.root.after(
+                0,
+                lambda: self.update_connection_indicator(
+                    self.ucd_status_indicator, ucd_connected
+                ),
+            )
+
+            # 检测CA连接
+            ca_connected = self.check_port_connection(is_ucd=False)
+            self.root.after(
+                0,
+                lambda: self.update_connection_indicator(
+                    self.ca_status_indicator, ca_connected
+                ),
+            )
+
+            # 更新状态栏
+            self.root.after(0, lambda: self.status_var.set("连接检测完成"))
+
+            # 重新启用所有控件
+            self.root.after(0, self.enable_com_widgets)
+        except Exception as e:
+            self.root.after(0, lambda: self.log_gui.log(f"连接检测出错: {e}"))
+            self.root.after(0, self.enable_com_widgets)
+
+    # 启动线程
+    threading.Thread(target=check_connections, daemon=True).start()
+
+
+def update_connection_indicator(app, indicator, connected):
+    """更新连接状态指示器颜色"""
+    self = app
+    if connected:
+        indicator.config(bg="green")
+    else:
+        indicator.config(bg="red")
+
+
+def check_port_connection(app, is_ucd=True):
+    """检测指定端口是否可以连接"""
+    self = app
+    try:
+        if is_ucd:
+            if self.ucd.status:
+                try:
+                    self.ucd.close()
+                except:
+                    pass
+            if not self.ucd.open(self.ucd_list_var.get()):
+                self.log_gui.log(
+                    f"设备 {self.ucd_list_var.get()} 异常，UCD323连接失败"
+                )
+                return False
+            else:
+                return True
+        else:
+            # 如果CA对象已存在，先关闭
+            if self.ca is not None:
+                try:
+                    self.ca.close()
+                except:
+                    pass
+            channel_value = self.ca_channel_var.get()
+            str_channel = f"{int(channel_value):02d}"
+            self.ca = CASerail()
+            self.ca.open(self.config.device_config["ca_com"], 19200, 7, "E", 2)
+            # data = self.ca.set_xyLv_Display()
+            data = self.ca.set_all_Display()
+            if data:
+                data = self.ca.setSynchMode(3)
+                data = self.ca.setMeasureSpeed(1)
+                if True:
+                    time.sleep(0.5)
+                    data = self.ca.setZeroCalibration()
+                channel_value = self.ca_channel_var.get()
+                str_channel = f"{int(channel_value):02d}"
+                data = self.ca.setChannel(str_channel)
+                return True
+            else:
+                self.log_gui.log(
+                    f"端口 {self.config.device_config["ca_com"]} 异常，色温仪连接失败"
+                )
+                self.ca.close()
+                self.ca = None
+                return False
+    except Exception as e:
+        self.log_gui.log(f"端口连接失败: {e}")
+        return False
+
+
+def enable_com_widgets(app):
+    """重新启用所有控件"""
+    self = app
+    self.check_button.configure(state="normal")
+    self.refresh_button.configure(state="normal")
+
+
+def disconnect_com_connections(app):
+    """断开所有串口连接"""
+    self = app
+    try:
+        # 断开TV连接
+        if self.ucd.status:
+            try:
+                self.ucd.close()
+            except:
+                pass
+            finally:
+                self.ucd.status = False
+                self.log_gui.log("UCD连接已断开")
+
+        # 断开CA连接
+        if self.ca is not None:
+            try:
+                self.ca.close()
+            except:
+                pass
+            finally:
+                self.ca = None
+                self.log_gui.log("CA连接已断开")
+
+        # 重新启用相关控件
+        self.enable_com_widgets()
+        self.ucd_status_indicator.config(bg="gray")
+        self.ca_status_indicator.config(bg="gray")
+        self.status_var.set("串口连接已断开")
+
+    except Exception as e:
+        self.log_gui.log(f"断开连接时发生错误: {str(e)}")
+        messagebox.showerror("错误", f"断开连接失败: {str(e)}")
+
+
diff --git a/app/tests/local_dimming.py b/app/tests/local_dimming.py
new file mode 100644
index 0000000..eec2318
--- /dev/null
+++ b/app/tests/local_dimming.py
@@ -0,0 +1,228 @@
+"""Local Dimming 测试逻辑（Step 4 重构）。
+
+从 pqAutomationApp.PQAutomationApp 中搬迁。每个函数第一行 `self = app`
+以保留原有 `self.xxx` 属性访问不变。
+"""
+
+import threading
+import tkinter as tk
+from tkinter import filedialog, messagebox
+
+def start_local_dimming_test(app):
+    """开始 Local Dimming 测试"""
+    self = app
+    # 检查设备连接
+    if not self.ca or not self.ucd.status:
+        messagebox.showerror("错误", "请先连接 CA410 和 UCD323")
+        return
+
+    # 禁用按钮
+    self.ld_start_btn.config(state=tk.DISABLED)
+    self.ld_stop_btn.config(state=tk.NORMAL)
+    self.ld_save_btn.config(state=tk.DISABLED)
+
+    # 清空结果
+    for item in self.ld_tree.get_children():
+        self.ld_tree.delete(item)
+
+    # 获取配置
+    wait_time = float(self.ld_wait_time_var.get())
+
+    # 在新线程中执行测试
+    def run_test():
+        from utils.local_dimming_test import LocalDimmingTest, LocalDimmingController
+
+        # 从设备当前 timing 获取分辨率
+        ld_ctrl = LocalDimmingController(self.ucd)
+        cur_w, cur_h = ld_ctrl.get_current_resolution()
+        resolution = f"{cur_w}x{cur_h}"
+
+        ld_test = LocalDimmingTest(
+            self.ucd,
+            self.ca,
+            log_callback=self.log_gui.log,
+        )
+
+        ld_test.wait_time = wait_time
+
+        results = ld_test.run_test(resolution=resolution)
+
+        # 保存到实例变量
+        self.ld_test_instance = ld_test
+        self.ld_test_results = results
+
+        # 更新结果显示
+        self.root.after(0, lambda: self.update_ld_results(results))
+
+        # 清理临时文件
+        ld_test.cleanup()
+
+        # 恢复按钮状态
+        self.root.after(0, lambda: self.ld_start_btn.config(state=tk.NORMAL))
+        self.root.after(0, lambda: self.ld_stop_btn.config(state=tk.DISABLED))
+        self.root.after(0, lambda: self.ld_save_btn.config(state=tk.NORMAL))
+
+    threading.Thread(target=run_test, daemon=True).start()
+
+
+def update_ld_results(app, results):
+    """更新 Local Dimming 结果显示"""
+    self = app
+    for percentage, x, y, lv, X, Y, Z in results:
+        self.ld_tree.insert(
+            "",
+            tk.END,
+            values=(f"{percentage}%", f"{lv:.2f}", f"{x:.4f}", f"{y:.4f}"),
+        )
+
+
+def stop_local_dimming_test(app):
+    """停止 Local Dimming 测试"""
+    self = app
+    if hasattr(self, "ld_test_instance"):
+        self.ld_test_instance.stop()
+
+
+def send_ld_window(app, percentage):
+    """发送指定百分比的窗口"""
+    self = app
+    if not self.ucd.status:
+        messagebox.showwarning("警告", "请先连接 UCD323 设备")
+        return
+
+    self.log_gui.log(f"🔆 发送 {percentage}% 窗口...")
+
+    # 记录当前百分比（用于测量）
+    self.current_ld_percentage = percentage
+
+    def send():
+        from utils.local_dimming_test import LocalDimmingController
+
+        ld_controller = LocalDimmingController(self.ucd)
+
+        # 从设备当前 timing 获取分辨率
+        width, height = ld_controller.get_current_resolution()
+
+        # 生成并发送图片
+        success = ld_controller.send_window_pattern_with_resolution(
+            percentage, width, height
+        )
+
+        if success:
+            self.root.after(
+                0, lambda: self.log_gui.log(f"✅ {percentage}% 窗口已发送")
+            )
+        else:
+            self.root.after(
+                0, lambda: self.log_gui.log(f"❌ {percentage}% 窗口发送失败")
+            )
+
+    threading.Thread(target=send, daemon=True).start()
+
+
+def measure_ld_luminance(app):
+    """测量当前亮度"""
+    self = app
+    if not self.ca:
+        messagebox.showwarning("警告", "请先连接 CA410 色度计")
+        return
+
+    if self.current_ld_percentage is None:
+        messagebox.showinfo("提示", "请先发送一个窗口图案")
+        return
+
+    self.log_gui.log("📏 正在采集亮度...")
+
+    def measure():
+        try:
+            x, y, lv, X, Y, Z = self.ca.readAllDisplay()
+
+            if lv is not None:
+                import datetime
+
+                timestamp = datetime.datetime.now().strftime("%H:%M:%S")
+
+                # 更新显示
+                self.root.after(
+                    0,
+                    lambda: self.ld_result_label.config(
+                        text=f"亮度: {lv:.2f} cd/m² | x: {x:.4f} | y: {y:.4f}"
+                    ),
+                )
+
+                # 添加到表格
+                self.root.after(
+                    0,
+                    lambda: self.ld_tree.insert(
+                        "",
+                        tk.END,
+                        values=(
+                            f"{self.current_ld_percentage}%",
+                            f"{lv:.2f}",
+                            f"{x:.4f}",
+                            f"{y:.4f}",
+                            timestamp,
+                        ),
+                    ),
+                )
+
+                self.root.after(
+                    0, lambda: self.log_gui.log(f"✅ 采集完成: {lv:.2f} cd/m²")
+                )
+            else:
+                self.root.after(0, lambda: self.log_gui.log("❌ 采集失败"))
+
+        except Exception as e:
+            self.root.after(0, lambda: self.log_gui.log(f"❌ 采集异常: {str(e)}"))
+
+    threading.Thread(target=measure, daemon=True).start()
+
+
+def clear_ld_records(app):
+    """清空测试记录"""
+    self = app
+    for item in self.ld_tree.get_children():
+        self.ld_tree.delete(item)
+    self.ld_result_label.config(text="亮度: -- cd/m² | x: -- | y: --")
+    self.current_ld_percentage = None
+    self.log_gui.log("🗑️ 测试记录已清空")
+
+
+def save_local_dimming_results(app):
+    """保存 Local Dimming 结果"""
+    self = app
+    from tkinter import filedialog
+    import csv
+    import datetime
+
+    if len(self.ld_tree.get_children()) == 0:
+        messagebox.showinfo("提示", "没有可保存的数据")
+        return
+
+    default_name = f"LocalDimming_{datetime.datetime.now().strftime('%Y%m%d_%H%M%S')}.csv"
+
+    save_path = filedialog.asksaveasfilename(
+        title="保存测试结果",
+        initialfile=default_name,
+        defaultextension=".csv",
+        filetypes=[("CSV 文件", "*.csv"), ("所有文件", "*.*")],
+    )
+
+    if not save_path:
+        return
+
+    try:
+        with open(save_path, "w", newline="", encoding="utf-8-sig") as f:
+            writer = csv.writer(f)
+            writer.writerow(["窗口百分比", "亮度 (cd/m²)", "x", "y", "时间"])
+
+            for item in self.ld_tree.get_children():
+                values = self.ld_tree.item(item, "values")
+                writer.writerow(values)
+
+        self.log_gui.log(f"✓ 测试结果已保存: {save_path}")
+        messagebox.showinfo("成功", f"测试结果已保存到:\n{save_path}")
+
+    except Exception as e:
+        self.log_gui.log(f"❌ 保存失败: {str(e)}")
+        messagebox.showerror("错误", f"保存失败: {str(e)}")
diff --git a/pqAutomationApp.py b/pqAutomationApp.py
index 9ebcfc0..0af5bb3 100644
--- a/pqAutomationApp.py
+++ b/pqAutomationApp.py
@@ -65,6 +65,31 @@ from app.views.chart_frame import (
     on_chart_tab_changed as _cf_on_chart_tab_changed,
     update_chart_tabs_state as _cf_update_chart_tabs_state,
 )
+from app.config_io import (
+    clear_config_file as _cfg_clear_config_file,
+    get_config_path as _cfg_get_config_path,
+    load_pq_config as _cfg_load_pq_config,
+    save_pq_config as _cfg_save_pq_config,
+)
+from app.tests.local_dimming import (
+    clear_ld_records as _ld_clear_ld_records,
+    measure_ld_luminance as _ld_measure_ld_luminance,
+    save_local_dimming_results as _ld_save_local_dimming_results,
+    send_ld_window as _ld_send_ld_window,
+    start_local_dimming_test as _ld_start_local_dimming_test,
+    stop_local_dimming_test as _ld_stop_local_dimming_test,
+    update_ld_results as _ld_update_ld_results,
+)
+from app.device.connection import (
+    check_com_connections as _dev_check_com_connections,
+    check_port_connection as _dev_check_port_connection,
+    disconnect_com_connections as _dev_disconnect_com_connections,
+    enable_com_widgets as _dev_enable_com_widgets,
+    get_available_com_ports as _dev_get_available_com_ports,
+    get_available_ucd_ports as _dev_get_available_ucd_ports,
+    refresh_com_ports as _dev_refresh_com_ports,
+    update_connection_indicator as _dev_update_connection_indicator,
+)
 
 plt.rcParams["font.family"] = ["sans-serif"]
 plt.rcParams["font.sans-serif"] = ["Microsoft YaHei"]
@@ -187,28 +212,8 @@ class PQAutomationApp:
         self.status_bar.pack(side=tk.BOTTOM, fill=tk.X)
 
     def get_config_path(self):
-        """获取配置文件的完整路径（兼容打包后的程序）"""
-        import os
-        import sys
-
-        # 判断是否是打包后的程序
-        if getattr(sys, "frozen", False):
-            # 打包后：使用可执行文件所在目录
-            base_path = os.path.dirname(sys.executable)
-        else:
-            # 开发环境：使用脚本所在目录
-            base_path = os.path.dirname(os.path.abspath(__file__))
-
-        # 构建配置文件路径
-        config_dir = os.path.join(base_path, "settings")
-        config_file = os.path.join(config_dir, "pq_config.json")
-
-        # 确保 settings 目录存在
-        if not os.path.exists(config_dir):
-            os.makedirs(config_dir)
-
-        return config_file
-
+        """转发到 app.config_io.get_config_path（Step 4 重构）"""
+        return _cfg_get_config_path(self)
     def initialize_default_test_type(self):
         """初始化默认测试类型（在所有控件创建完成后调用）"""
         try:
@@ -1514,187 +1519,21 @@ class PQAutomationApp:
         ca_channel_combo.bind("<<ComboboxSelected>>", self.update_config)
 
     def get_available_ucd_ports(self):
-        """获取可用的UCD端口列表"""
-        return self.ucd.search_device()
-
+        return _dev_get_available_ucd_ports(self)
     def get_available_com_ports(self):
-        """获取可用的COM端口列表"""
-        try:
-            import serial.tools.list_ports
-
-            ports = serial.tools.list_ports.comports()
-            return [port.device for port in ports]
-        except Exception as e:
-            self.log_gui.log(f"获取COM端口列表出错: {e}")
-            return []
-
+        return _dev_get_available_com_ports(self)
     def refresh_com_ports(self):
-        """刷新COM端口列表"""
-        available_ports = self.get_available_com_ports()
-        available_list = self.get_available_ucd_ports()
-
-        # 更新UCD列表的下拉框选项
-        ucd_list_current = self.ucd_list_var.get()
-        if ucd_list_current not in available_list:
-            self.ucd_list_var.set(available_list[0] if available_list else "")
-        self.ucd_list_combo.config(values=available_list)
-
-        # 更新CA端口的下拉框选项
-        ca_com_current = self.ca_com_var.get()
-        if ca_com_current not in available_ports:
-            self.ca_com_var.set(
-                available_ports[1]
-                if len(available_ports) > 1
-                else (available_ports[0] if available_ports else "")
-            )
-        self.ca_com_combo.config(values=available_ports)
-
-        # 重置连接状态指示器为灰色
-        if hasattr(self, "ucd_status_indicator"):
-            self.ucd_status_indicator.config(bg="gray")
-        if hasattr(self, "ca_status_indicator"):
-            self.ca_status_indicator.config(bg="gray")
-
-        self.update_config()
-
+        return _dev_refresh_com_ports(self)
     def check_com_connections(self):
-        """检测COM端口连接状态"""
-        # 禁用连接按钮，防止重复点击
-        self.check_button.configure(state="disabled")
-        self.refresh_button.configure(state="disabled")
-
-        # 更新状态栏
-        self.status_var.set("正在检测连接...")
-        self.root.update()
-
-        # 使用线程进行连接检测
-        def check_connections():
-            try:
-                # 检测TV连接
-                ucd_connected = self.check_port_connection(is_ucd=True)
-                self.root.after(
-                    0,
-                    lambda: self.update_connection_indicator(
-                        self.ucd_status_indicator, ucd_connected
-                    ),
-                )
-
-                # 检测CA连接
-                ca_connected = self.check_port_connection(is_ucd=False)
-                self.root.after(
-                    0,
-                    lambda: self.update_connection_indicator(
-                        self.ca_status_indicator, ca_connected
-                    ),
-                )
-
-                # 更新状态栏
-                self.root.after(0, lambda: self.status_var.set("连接检测完成"))
-
-                # 重新启用所有控件
-                self.root.after(0, self.enable_com_widgets)
-            except Exception as e:
-                self.root.after(0, lambda: self.log_gui.log(f"连接检测出错: {e}"))
-                self.root.after(0, self.enable_com_widgets)
-
-        # 启动线程
-        threading.Thread(target=check_connections, daemon=True).start()
-
+        return _dev_check_com_connections(self)
     def update_connection_indicator(self, indicator, connected):
-        """更新连接状态指示器颜色"""
-        if connected:
-            indicator.config(bg="green")
-        else:
-            indicator.config(bg="red")
-
+        return _dev_update_connection_indicator(self, indicator, connected)
     def check_port_connection(self, is_ucd=True):
-        """检测指定端口是否可以连接"""
-        try:
-            if is_ucd:
-                if self.ucd.status:
-                    try:
-                        self.ucd.close()
-                    except:
-                        pass
-                if not self.ucd.open(self.ucd_list_var.get()):
-                    self.log_gui.log(
-                        f"设备 {self.ucd_list_var.get()} 异常，UCD323连接失败"
-                    )
-                    return False
-                else:
-                    return True
-            else:
-                # 如果CA对象已存在，先关闭
-                if self.ca is not None:
-                    try:
-                        self.ca.close()
-                    except:
-                        pass
-                channel_value = self.ca_channel_var.get()
-                str_channel = f"{int(channel_value):02d}"
-                self.ca = CASerail()
-                self.ca.open(self.config.device_config["ca_com"], 19200, 7, "E", 2)
-                # data = self.ca.set_xyLv_Display()
-                data = self.ca.set_all_Display()
-                if data:
-                    data = self.ca.setSynchMode(3)
-                    data = self.ca.setMeasureSpeed(1)
-                    if True:
-                        time.sleep(0.5)
-                        data = self.ca.setZeroCalibration()
-                    channel_value = self.ca_channel_var.get()
-                    str_channel = f"{int(channel_value):02d}"
-                    data = self.ca.setChannel(str_channel)
-                    return True
-                else:
-                    self.log_gui.log(
-                        f"端口 {self.config.device_config["ca_com"]} 异常，色温仪连接失败"
-                    )
-                    self.ca.close()
-                    self.ca = None
-                    return False
-        except Exception as e:
-            self.log_gui.log(f"端口连接失败: {e}")
-            return False
-
+        return _dev_check_port_connection(self, is_ucd)
     def enable_com_widgets(self):
-        """重新启用所有控件"""
-        self.check_button.configure(state="normal")
-        self.refresh_button.configure(state="normal")
-
+        return _dev_enable_com_widgets(self)
     def disconnect_com_connections(self):
-        """断开所有串口连接"""
-        try:
-            # 断开TV连接
-            if self.ucd.status:
-                try:
-                    self.ucd.close()
-                except:
-                    pass
-                finally:
-                    self.ucd.status = False
-                    self.log_gui.log("UCD连接已断开")
-
-            # 断开CA连接
-            if self.ca is not None:
-                try:
-                    self.ca.close()
-                except:
-                    pass
-                finally:
-                    self.ca = None
-                    self.log_gui.log("CA连接已断开")
-
-            # 重新启用相关控件
-            self.enable_com_widgets()
-            self.ucd_status_indicator.config(bg="gray")
-            self.ca_status_indicator.config(bg="gray")
-            self.status_var.set("串口连接已断开")
-
-        except Exception as e:
-            self.log_gui.log(f"断开连接时发生错误: {str(e)}")
-            messagebox.showerror("错误", f"断开连接失败: {str(e)}")
-
+        return _dev_disconnect_com_connections(self)
     def create_test_type_frame(self):
         """创建测试类型选择区域（侧边栏形式）"""
         # 设置测试类型变量
@@ -6517,34 +6356,11 @@ class PQAutomationApp:
             self.log_gui.log(f"❌ 屏模组信号格式更改失败: {str(e)}")
 
     def load_pq_config(self):
-        """加载PQ配置（兼容打包后的程序）"""
-        try:
-            # ✅ 使用 self.config_file（已经是动态路径）
-            if os.path.exists(self.config_file):
-                with open(self.config_file, "r", encoding="utf-8") as f:
-                    config_dict = json.load(f)
-                    self.config.from_dict(config_dict)
-                    if hasattr(self, "log_gui"):
-                        self.log_gui.log("✓ 配置文件加载成功")
-            else:
-                if hasattr(self, "log_gui"):
-                    self.log_gui.log("⚠️ 配置文件不存在，使用默认配置")
-        except Exception as e:
-            if hasattr(self, "log_gui"):
-                self.log_gui.log(f"⚠️ 加载配置文件失败: {str(e)}，使用默认配置")
-
+        """转发到 app.config_io.load_pq_config（Step 4 重构）"""
+        return _cfg_load_pq_config(self)
     def save_pq_config(self):
-        """保存PQ配置（兼容打包后的程序）"""
-        try:
-            # 确保目录存在
-            os.makedirs(os.path.dirname(self.config_file), exist_ok=True)
-
-            # 保存配置
-            self.config.save_to_file(self.config_file)
-        except Exception as e:
-            if hasattr(self, "log_gui"):
-                self.log_gui.log(f"保存配置文件失败: {str(e)}")
-
+        """转发到 app.config_io.save_pq_config（Step 4 重构）"""
+        return _cfg_save_pq_config(self)
     def on_closing(self):
         """窗口关闭时的处理"""
         try:
@@ -6842,272 +6658,29 @@ class PQAutomationApp:
         self.log_gui.log("✓ HDR 单步调试面板已打开（独立窗口）")
 
     def clear_config_file(self):
-        """清理配置文件（兼容打包后的程序）"""
-        from tkinter import messagebox
-
-        config_file = self.get_config_path()
-
-        try:
-            if os.path.exists(config_file):
-                os.remove(config_file)
-                self.config_cleared = True
-                messagebox.showinfo("提示", "✓ 清理成功")
-                self.log_gui.log("✓ 配置文件清理成功")
-            else:
-                messagebox.showinfo("提示", "配置文件不存在")
-                self.log_gui.log("⚠️ 配置文件不存在")
-
-        except Exception as e:
-            messagebox.showerror("错误", "❌ 清理失败")
-            self.log_gui.log(f"❌ 配置文件清理失败: {str(e)}")
-
+        """转发到 app.config_io.clear_config_file（Step 4 重构）"""
+        return _cfg_clear_config_file(self)
     def start_local_dimming_test(self):
-        """开始 Local Dimming 测试"""
-        # 检查设备连接
-        if not self.ca or not self.ucd.status:
-            messagebox.showerror("错误", "请先连接 CA410 和 UCD323")
-            return
-
-        # 禁用按钮
-        self.ld_start_btn.config(state=tk.DISABLED)
-        self.ld_stop_btn.config(state=tk.NORMAL)
-        self.ld_save_btn.config(state=tk.DISABLED)
-
-        # 清空结果
-        for item in self.ld_tree.get_children():
-            self.ld_tree.delete(item)
-
-        # 获取配置
-        wait_time = float(self.ld_wait_time_var.get())
-
-        # 在新线程中执行测试
-        def run_test():
-            from utils.local_dimming_test import LocalDimmingTest, LocalDimmingController
-
-            # 从设备当前 timing 获取分辨率
-            ld_ctrl = LocalDimmingController(self.ucd)
-            cur_w, cur_h = ld_ctrl.get_current_resolution()
-            resolution = f"{cur_w}x{cur_h}"
-
-            ld_test = LocalDimmingTest(
-                self.ucd,
-                self.ca,
-                log_callback=self.log_gui.log,
-            )
-
-            ld_test.wait_time = wait_time
-
-            results = ld_test.run_test(resolution=resolution)
-
-            # 保存到实例变量
-            self.ld_test_instance = ld_test
-            self.ld_test_results = results
-
-            # 更新结果显示
-            self.root.after(0, lambda: self.update_ld_results(results))
-
-            # 清理临时文件
-            ld_test.cleanup()
-
-            # 恢复按钮状态
-            self.root.after(0, lambda: self.ld_start_btn.config(state=tk.NORMAL))
-            self.root.after(0, lambda: self.ld_stop_btn.config(state=tk.DISABLED))
-            self.root.after(0, lambda: self.ld_save_btn.config(state=tk.NORMAL))
-
-        threading.Thread(target=run_test, daemon=True).start()
-
+        """转发到 app.tests.local_dimming.start_local_dimming_test（Step 4 重构）"""
+        return _ld_start_local_dimming_test(self)
     def update_ld_results(self, results):
-        """更新 Local Dimming 结果显示"""
-        for percentage, x, y, lv, X, Y, Z in results:
-            self.ld_tree.insert(
-                "",
-                tk.END,
-                values=(f"{percentage}%", f"{lv:.2f}", f"{x:.4f}", f"{y:.4f}"),
-            )
-
+        """转发到 app.tests.local_dimming.update_ld_results（Step 4 重构）"""
+        return _ld_update_ld_results(self, results)
     def stop_local_dimming_test(self):
-        """停止 Local Dimming 测试"""
-        if hasattr(self, "ld_test_instance"):
-            self.ld_test_instance.stop()
-
-    def save_local_dimming_results(self):
-        """保存 Local Dimming 结果"""
-        from tkinter import filedialog
-        import csv
-        import datetime
-
-        default_name = f"LocalDimming_{datetime.datetime.now().strftime('%Y%m%d_%H%M%S')}.csv"
-
-        save_path = filedialog.asksaveasfilename(
-            title="保存测试结果",
-            initialfile=default_name,
-            defaultextension=".csv",
-            filetypes=[("CSV 文件", "*.csv"), ("所有文件", "*.*")],
-        )
-
-        if not save_path:
-            return
-
-        try:
-            with open(save_path, "w", newline="", encoding="utf-8-sig") as f:
-                writer = csv.writer(f)
-                writer.writerow(["窗口百分比", "x", "y", "亮度 (cd/m²)", "X", "Y", "Z"])
-
-                for item in self.ld_tree.get_children():
-                    values = self.ld_tree.item(item, "values")
-                    # 从 self.ld_test_results 获取完整数据
-                    percentage_str = values[0]
-                    percentage = int(percentage_str.replace("%", ""))
-
-                    # 找到对应的完整数据
-                    for p, x, y, lv, X, Y, Z in self.ld_test_results:
-                        if p == percentage:
-                            writer.writerow([f"{p}%", x, y, lv, X, Y, Z])
-                            break
-
-            self.log_gui.log(f"✓ 测试结果已保存: {save_path}")
-            messagebox.showinfo("成功", f"测试结果已保存到:\n{save_path}")
-
-        except Exception as e:
-            self.log_gui.log(f"❌ 保存失败: {str(e)}")
-            messagebox.showerror("错误", f"保存失败: {str(e)}")
-
+        """转发到 app.tests.local_dimming.stop_local_dimming_test（Step 4 重构）"""
+        return _ld_stop_local_dimming_test(self)
     def send_ld_window(self, percentage):
-        """发送指定百分比的窗口"""
-        if not self.ucd.status:
-            messagebox.showwarning("警告", "请先连接 UCD323 设备")
-            return
-
-        self.log_gui.log(f"🔆 发送 {percentage}% 窗口...")
-
-        # 记录当前百分比（用于测量）
-        self.current_ld_percentage = percentage
-
-        def send():
-            from utils.local_dimming_test import LocalDimmingController
-
-            ld_controller = LocalDimmingController(self.ucd)
-
-            # 从设备当前 timing 获取分辨率
-            width, height = ld_controller.get_current_resolution()
-
-            # 生成并发送图片
-            success = ld_controller.send_window_pattern_with_resolution(
-                percentage, width, height
-            )
-
-            if success:
-                self.root.after(
-                    0, lambda: self.log_gui.log(f"✅ {percentage}% 窗口已发送")
-                )
-            else:
-                self.root.after(
-                    0, lambda: self.log_gui.log(f"❌ {percentage}% 窗口发送失败")
-                )
-
-        threading.Thread(target=send, daemon=True).start()
-
+        """转发到 app.tests.local_dimming.send_ld_window（Step 4 重构）"""
+        return _ld_send_ld_window(self, percentage)
     def measure_ld_luminance(self):
-        """测量当前亮度"""
-        if not self.ca:
-            messagebox.showwarning("警告", "请先连接 CA410 色度计")
-            return
-
-        if self.current_ld_percentage is None:
-            messagebox.showinfo("提示", "请先发送一个窗口图案")
-            return
-
-        self.log_gui.log("📏 正在采集亮度...")
-
-        def measure():
-            try:
-                x, y, lv, X, Y, Z = self.ca.readAllDisplay()
-
-                if lv is not None:
-                    import datetime
-
-                    timestamp = datetime.datetime.now().strftime("%H:%M:%S")
-
-                    # 更新显示
-                    self.root.after(
-                        0,
-                        lambda: self.ld_result_label.config(
-                            text=f"亮度: {lv:.2f} cd/m² | x: {x:.4f} | y: {y:.4f}"
-                        ),
-                    )
-
-                    # 添加到表格
-                    self.root.after(
-                        0,
-                        lambda: self.ld_tree.insert(
-                            "",
-                            tk.END,
-                            values=(
-                                f"{self.current_ld_percentage}%",
-                                f"{lv:.2f}",
-                                f"{x:.4f}",
-                                f"{y:.4f}",
-                                timestamp,
-                            ),
-                        ),
-                    )
-
-                    self.root.after(
-                        0, lambda: self.log_gui.log(f"✅ 采集完成: {lv:.2f} cd/m²")
-                    )
-                else:
-                    self.root.after(0, lambda: self.log_gui.log("❌ 采集失败"))
-
-            except Exception as e:
-                self.root.after(0, lambda: self.log_gui.log(f"❌ 采集异常: {str(e)}"))
-
-        threading.Thread(target=measure, daemon=True).start()
-
+        """转发到 app.tests.local_dimming.measure_ld_luminance（Step 4 重构）"""
+        return _ld_measure_ld_luminance(self)
     def clear_ld_records(self):
-        """清空测试记录"""
-        for item in self.ld_tree.get_children():
-            self.ld_tree.delete(item)
-        self.ld_result_label.config(text="亮度: -- cd/m² | x: -- | y: --")
-        self.current_ld_percentage = None
-        self.log_gui.log("🗑️ 测试记录已清空")
-
+        """转发到 app.tests.local_dimming.clear_ld_records（Step 4 重构）"""
+        return _ld_clear_ld_records(self)
     def save_local_dimming_results(self):
-        """保存 Local Dimming 结果"""
-        from tkinter import filedialog
-        import csv
-        import datetime
-
-        if len(self.ld_tree.get_children()) == 0:
-            messagebox.showinfo("提示", "没有可保存的数据")
-            return
-
-        default_name = f"LocalDimming_{datetime.datetime.now().strftime('%Y%m%d_%H%M%S')}.csv"
-
-        save_path = filedialog.asksaveasfilename(
-            title="保存测试结果",
-            initialfile=default_name,
-            defaultextension=".csv",
-            filetypes=[("CSV 文件", "*.csv"), ("所有文件", "*.*")],
-        )
-
-        if not save_path:
-            return
-
-        try:
-            with open(save_path, "w", newline="", encoding="utf-8-sig") as f:
-                writer = csv.writer(f)
-                writer.writerow(["窗口百分比", "亮度 (cd/m²)", "x", "y", "时间"])
-
-                for item in self.ld_tree.get_children():
-                    values = self.ld_tree.item(item, "values")
-                    writer.writerow(values)
-
-            self.log_gui.log(f"✓ 测试结果已保存: {save_path}")
-            messagebox.showinfo("成功", f"测试结果已保存到:\n{save_path}")
-
-        except Exception as e:
-            self.log_gui.log(f"❌ 保存失败: {str(e)}")
-            messagebox.showerror("错误", f"保存失败: {str(e)}")
+        """转发到 app.tests.local_dimming.save_local_dimming_results（Step 4 重构）"""
+        return _ld_save_local_dimming_results(self)
 
 
 def main():