Applies To:
  • CitectSCADA 1.00 1.01 1.10 1.11 1.20 2.00 2.01 3.00

Question: What is the size of the DISK PLCs? 

The DISK PLCs are usually tiny, typical 1 to 10 K in size, so you can have as many and as large as required. In Versions 1.xx to 2.xx the I/O Server kept all DISK PLC files open so it was better to have fewer larger files as this reduces the use of file handles. In version 3.xx and later a new DISKPLC driver will open and close each file as required so there is less demand on file handles. However I feel it is still better to have fewer larger DISK PLC files. Also with this new driver you don't need to use CtDisk any more. When you reference a variable which does not exist this driver will just create more space in the DISK PLC file. You may also use this driver on Version 2.xx and it is on the Citect BBS.