Procedures and communication unit for making a diagnosis of a field device

A method for making a diagnosis of a field device (10) a system of process automation technology (2), a plurality of inter-communications link field devices (10, 18, 22, 24, 26), said method comprising the following steps: A) Automatic creation of a device diagnostic message in the field device (10) as part of a self-diagnosis of the field device (10); received B) Automated applying to the field device (10) associated diagnostic validation algorithm (in the information concerning the system state of at least one further field device 18, 22, 24, 26) of the installation (2) on the devices diagnostic message and automated determining from whether to evaluate the device diagnostics message or discard is.