Applies To:
  • CitectSCADA 5.xx

I have 80 trends in Citect with 30 trend files each. After a while I get gaps in my trends. Sometimes it works fine but then the gaps come back. What can I do to solve this? 

One thing that usually cause this problem is that the disk access time is slow for the directory where all the trend files are located. More files in one directory will increase the access time to that directory. In this case (if all the trend files are in the same place - 2400 files) Citect has to wait for the OS to get the access. If there are SCSI discs with fast access time the maximum number of files you should have in one directory could be increased.

Experience has shown that if you split the trend files to more directories this problem will disappear. To give an exact number of trend files per directory is difficult depending on several factors. CPU speed, disc speed, type of OS, RAM memory, disk access per second, CPU load, disc controller, CACHE on disc controller and so on. To give a hint of the max number of files you should have in one directory I would say 500 - 1000 files.