Applies To:
  • CitectSCADA 5.42, 5.50
  • CitectHMI 5.42, 5.50

Since upgrading to CitectSCADA version 5.42 I have found gaps in all my trend displays. It seems to coincide when one PLC is offline, however I am trending data from several PLCs and they seem to be affected too. 

By default in CitectSCADA version 5.42, trend server requests to the I/O Servers are not blocked by I/O Device. When an I/O Device is offline all trend requests of the I/O Server can be lost. To ensure continuity you can set the following parameter on the trend servers: [trend]blockbyiodevice=1. This is the default setting in CitectSCADA version 5.50.