Method for operating an automation engineering field device

at a method for operating a field device of automation technology, the above a bus system to a superordinated Unit is connected and having an identifier type the the field device identified, in addition to an identifier KF1, at least one alternative identifier AKF1 that like a Field Device Type identified in the field device F1 stored. This alternative identifier is AKF1 on request to the parent Unit SPS received, if the parent Unit PLC which sent in previous inquiries identifier not KF1 as valid ID accepted. This replacement of a field device is simple and quickly.