Field device for determining a process variable in process automation, having - sensor means for detecting and converting the process variable into an electrical measuring signal , - an evaluation facility for processing the measuring signal to form a measured value , - an output facility for outputting the measured value and - a diagnostic facility for monitoring the function of the field device and generating and outputting binary status reports , wherein the diagnostic facility is embodied to report at least one predetermined error (F2), upon detection of the same, by way of a first binary status report , to identify the output measured value as temporarily invalid by way of a second binary status report and/or to trigger the output facility to output a replacement value instead of the measured value , characterised in that - the diagnostic facility contains a first timer with a predetermined first expiration time (FRD) and a second timer with a predetermined second expiration time (FID), - the second expiration time (FID) is shorter than the first expiration time (FRD), - both timers are started upon detection of the error (F2) and are reset at the end of the detected error (F2), - the first timer triggers the output of the replacement value when the first expiration time (FRD) has elapsed and - the second timer reports the error (F2) by way of the first binary status report when the second expiration time (FID) has elapsed, wherein the report can be reset by an acknowledgment signal at a point in time at which the diagnostic facility identifies the output measured value as valid by way of the second binary status report . - sensor means for detecting and converting the process variable into an electrical measuring signal , - an evaluation facility for processing the measuring signal to form a measured value , - an output facility for outputting the measured value and - a diagnostic facility for monitoring the function of the field device and generating and outputting binary status reports , wherein the diagnostic facility is embodied to report at least one predetermined error (F2), upon detection of the same, by way of a first binary status report , to identify the output measured value as temporarily invalid by way of a second binary status report and/or to trigger the output facility to output a replacement value instead of the measured value , - the diagnostic facility contains a first timer with a predetermined first expiration time (FRD) and a second timer with a predetermined second expiration time (FID), - the second expiration time (FID) is shorter than the first expiration time (FRD), - both timers are started upon detection of the error (F2) and are reset at the end of the detected error (F2), - the first timer triggers the output of the replacement value when the first expiration time (FRD) has elapsed and - the second timer reports the error (F2) by way of the first binary status report when the second expiration time (FID) has elapsed, wherein the report can be reset by an acknowledgment signal at a point in time at which the diagnostic facility identifies the output measured value as valid by way of the second binary status report . <EOS>