diff --git a/README.md b/README.md
index 5c5719e..eb47613 100755
--- a/README.md
+++ b/README.md
@@ -35,6 +35,8 @@ Registers
 
 Both full-duplex and half-duplex RS232/485 transceivers are supported. Callback functions are provided to toggle Data Enable (DE) and Receiver Enable (/RE) pins.
 
+The response timeout (default 2000 ms) can be set with `setResponseTimeout(ms)` after `begin()`, e.g. to fail sooner when no slave is present.
+
 
 ## Installation
 
diff --git a/keywords.txt b/keywords.txt
index cf50a0a..d226fce 100644
--- a/keywords.txt
+++ b/keywords.txt
@@ -17,6 +17,7 @@ highWord	KEYWORD2
 LONG	KEYWORD2
 
 begin	KEYWORD2
+setResponseTimeout	KEYWORD2
 
 getResponseBuffer	KEYWORD2
 clearResponseBuffer	KEYWORD2
diff --git a/src/ModbusMaster.cpp b/src/ModbusMaster.cpp
index 4169e58..29d782e 100644
--- a/src/ModbusMaster.cpp
+++ b/src/ModbusMaster.cpp
@@ -46,6 +46,7 @@ ModbusMaster::ModbusMaster(void)
   _idle = 0;
   _preTransmission = 0;
   _postTransmission = 0;
+  _u16ResponseTimeoutMs = ku16MBResponseTimeout;
 }
 
 /**
@@ -73,6 +74,12 @@ void ModbusMaster::begin(uint8_t slave, Stream &serial)
 }
 
 
+void ModbusMaster::setResponseTimeout(uint16_t ms)
+{
+  _u16ResponseTimeoutMs = ms;
+}
+
+
 void ModbusMaster::beginTransmission(uint16_t u16Address)
 {
   _u16WriteAddress = u16Address;
@@ -797,7 +804,7 @@ uint8_t ModbusMaster::ModbusMasterTransaction(uint8_t u8MBFunction)
           break;
       }
     }
-    if ((millis() - u32StartTime) > ku16MBResponseTimeout)
+    if ((millis() - u32StartTime) > _u16ResponseTimeoutMs)
     {
       u8MBStatus = ku8MBResponseTimedOut;
     }
diff --git a/src/ModbusMaster.h b/src/ModbusMaster.h
index 8c433e6..0d767dd 100644
--- a/src/ModbusMaster.h
+++ b/src/ModbusMaster.h
@@ -217,6 +217,14 @@ class ModbusMaster
     uint8_t  readWriteMultipleRegisters(uint16_t, uint16_t, uint16_t, uint16_t);
     uint8_t  readWriteMultipleRegisters(uint16_t, uint16_t);
     
+    /**
+     * Set response timeout in milliseconds.
+     * Default is 2000 ms after begin(). Use a shorter value (e.g. 500) to fail
+     * sooner when no slave is present and reduce main loop blocking.
+     * @param ms timeout in milliseconds
+     */
+    void setResponseTimeout(uint16_t ms);
+    
   private:
     Stream* _serial;                                             ///< reference to serial port object
     uint8_t  _u8MBSlave;                                         ///< Modbus slave (1..255) initialized in begin()
@@ -249,8 +257,8 @@ class ModbusMaster
     static const uint8_t ku8MBReadWriteMultipleRegisters = 0x17; ///< Modbus function 0x17 Read Write Multiple Registers
     
     // Modbus timeout [milliseconds]
-    static const uint16_t ku16MBResponseTimeout          = 2000; ///< Modbus timeout [milliseconds]
-    
+    static const uint16_t ku16MBResponseTimeout          = 2000; ///< default
+    uint16_t _u16ResponseTimeoutMs;                              ///< runtime timeout
     // master function that conducts Modbus transactions
     uint8_t ModbusMasterTransaction(uint8_t u8MBFunction);