edit

modbus_tk/modbus_rtu.py

@@ -124,8 +124,10 @@ class RtuMaster(Master):
         self.use_sw_timeout = use_sw_timeout
 
     def _handle(self, request, expected_length):
+        print(request)
         self._send(request)
         response = self._serial.read(expected_length)
+        print(response)
         return response
 
     def _send(self, request):