Archive values after communication loss

[joelprasad]

Hello Team,
Once communication with the PLC is lost, my archive logs the last updated data. I want to log '0' in each tag once communication is lost. 
Please suggest. 

[ursulak]

Are you sure that your Historian does not contain these INVALID values while connection loss? Filter of historian screen? Time sorting while not synchronized clocks?

When by connection loss, you see on screen elements that linked variables get 0 and INVALID (red square) then also historian stores this. The time stamp of values with INVALID statusbit is the local clock (zenon PC) time of connection loss. Thus, when PLC is delivering process data with external time stamps (typical in energy protocols) but the PLC clock is not well time synchronized (has another time as PC with zenon) - then in historians the valid process data and INVALID indicated values while connection loss are not chronological.