Measuring access device, the field device and method for controlling access to a measuring instrument

A measuring instruments access device (100) receives a data packet (104) for a field device means (200, 200 ', 200' ', 200' '') and extracts an external address information (106) and a command information (105). The extracted information (105, 106) passes the measuring devices access device (100) to a management means (109) further, wherein said management means (109) a field-device characteristic from the external address information (106) in an internal address information (106 ') of the field devices (200, 'ubersetzet) and a request to the field device means (200, 200' 200 ', 200' ', 200' ', 200' ', 200' '') passes.