diff --git a/app.db b/app.db
index 9beb63e..53073ce 100644
Binary files a/app.db and b/app.db differ
diff --git a/src/main/java/com/iflytop/digester/underframework/connection/UfModbusRTUOverTCP.java b/src/main/java/com/iflytop/digester/underframework/connection/UfModbusRTUOverTCP.java
index 078a761..bb2402e 100644
--- a/src/main/java/com/iflytop/digester/underframework/connection/UfModbusRTUOverTCP.java
+++ b/src/main/java/com/iflytop/digester/underframework/connection/UfModbusRTUOverTCP.java
@@ -10,6 +10,10 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 public class UfModbusRTUOverTCP extends UfConnectionBase {
+    // host
+    public String host;
+    // port
+    public Integer port;
     // connection
     private Socket socket;
     // writer
@@ -19,41 +23,10 @@ public class UfModbusRTUOverTCP extends UfConnectionBase {
     // busy
     private Boolean isBusy = false;
 
-    // connections
-    private static final Map<String, UfModbusRTUOverTCP> connections = new HashMap<>();
-
-    // get connection
-    public static UfModbusRTUOverTCP getConnection(String host, Integer port) {
-        String key = host + ":" + port;
-        if ( connections.containsKey(key) ) {
-            return connections.get(key);
-        }
-
-        UfModbusRTUOverTCP con = new UfModbusRTUOverTCP();
-        con.connect(host, port);
-        connections.put(key, con);
-        return con;
-    }
-
-    @Override
-    synchronized public String execute(UfMdbActuatorCmd command) {
-        return "";
-    }
-
     @Override
     public void connect() {
-
-    }
-
-    // constructor
-    public UfModbusRTUOverTCP() {
-        this.isBusy = false;
-    }
-
-    // connect
-    public void connect( String host, Integer port ) {
         try {
-            this.socket = new Socket(host, port);
+            this.socket = new Socket(this.host, this.port);
             this.writer = new DataOutputStream(this.socket.getOutputStream());
             this.reader = this.socket.getInputStream();
         } catch (Exception e) {
@@ -61,6 +34,25 @@ public class UfModbusRTUOverTCP extends UfConnectionBase {
         }
     }
 
+    @Override
+    synchronized public String execute(UfMdbActuatorCmd command) {
+        if ( "03".equals(command.cmdId) ) {
+            Integer slaveId = Integer.parseInt(command.cmdFlags);
+            Integer address = Integer.parseInt(command.parameters);
+            Integer value = this.readHoldingRegister(slaveId, address);
+            return value.toString();
+        } else if ( "06".equals(command.cmdId) ) {
+            Integer slaveId = Integer.parseInt(command.cmdFlags);
+            String[] params = command.parameters.split(",");
+            Integer address = Integer.parseInt(params[0]);
+            Integer value = Integer.parseInt(params[1]);
+            this.writeHoldingRegister(slaveId, address, value);
+            return "";
+        } else {
+            throw new RuntimeException("Modbus RTU over TCP: unknown command");
+        }
+    }
+
     // write holding register
     public void writeHoldingRegister( Integer slaveId, Integer address, Integer value ) {
         byte[] cmd = new byte[8];
diff --git a/src/main/java/com/iflytop/digester/underframework/web/api/TsApiActuatorCommand.java b/src/main/java/com/iflytop/digester/underframework/web/api/TsApiActuatorCommand.java
index 8fff3fd..19e2aea 100644
--- a/src/main/java/com/iflytop/digester/underframework/web/api/TsApiActuatorCommand.java
+++ b/src/main/java/com/iflytop/digester/underframework/web/api/TsApiActuatorCommand.java
@@ -42,11 +42,11 @@ public class TsApiActuatorCommand extends UfApiControllerBase {
     @ResponseBody
     public UfApiResponse execute(@RequestBody UfMdbActuatorCmd actuatorCmd ) {
         try {
-            UfActuatorCmdExecutor.execute(actuatorCmd);
+            String result = UfActuatorCmdExecutor.execute(actuatorCmd);
+            return success(Map.of("result", result));
         } catch ( Exception e ) {
             return error(e.getMessage());
         }
-        return success();
     }
 
     @PostMapping("/api/actuator-cmd/connection-list")
diff --git a/src/main/resources/application.yml b/src/main/resources/application.yml
index 37d6fa1..01c44af 100644
--- a/src/main/resources/application.yml
+++ b/src/main/resources/application.yml
@@ -18,7 +18,7 @@ device:
     - name : modbus
       key : modbus
       type : ModbusRTUOverTCP
-      host: 182.168.8.10
+      host: 127.0.0.1
       port: 502
 
 mqtt-broker:
diff --git a/web b/web
index 54eb432..b69f9ba 160000
--- a/web
+++ b/web
@@ -1 +1 @@
-Subproject commit 54eb4327c3a74e6aae926d4752b18439f62091f0
+Subproject commit b69f9ba8503f7247097d2eaa9dad06cc36582fec