edit

modbus_tk/modbus_rtu.py

@@ -125,7 +125,7 @@ class RtuMaster(Master):
 
     def _handle(self, request, expected_length):
         print(request)
-        self._send(request)
+        self._serial.write(request)
         print(expected_length)
         response = self._serial.read(expected_length)
         print(response)