Applies To:
  • CitectSCADA 5.XX
  • CitectHMI 5.XX

When changing pages in the CitectHMI/SCADA project using an Internet Display Client, it may appear that the client hangs periodically. Under typical conditions the CitectHMI/SCADA IDC should operate at close to the performance of a standard display client. 

The Internet Display Client uses FTP (File Transfer Protocol) to get the required elements of the project which includes the necessary files for displaying pages. If a file does not exist in its local project then it is requested from the FTP server via the internet cache on your Client. If the file in the cache is up to date then that is what is returned otherwise it asks the CitectHMI/SCADA FTP server to return the file. This is where things can go wrong.

Sometimes there maybe a problem with a project where it is requesting files that do not exist on the server. This means that each time that operation is requested the full operation occurs back to the FTP server where it fails. The CitectHMI/SCADA client will then take fall back action.

The problem is made even worse if the project has a lot of included projects. One of the fallback methods of the Client is to search for the file in each included project on the server. This can take time to complete and thus give the impression that the Client is periodically hanging.

There are a couple of known issues that users should watch out for if they are affected by this problem.

1. Setting [Animator]FastDisplay=1 (CTF Files) on the client when these pages are not being compiled at development time and therefore not available on the server. This adds to a second fallback in addition to the one above. It will do the same search on the project and included projects for the standard display type (CTG files) once the search for CTF files fail. Refer KB3821

2. If you have upgraded from a version prior to v5.30 where CitectHMI/SCADA did not support Long File Names. When changes were made to support long filenames it added a new fall back. First if a page was requested it would look for the long file name version. If it could not find it in the project or any of the projects included projects then it would search again for the page files with the old 8.3 DOS format. To fix this issue you need to run Update Pages in the Graphics builder on the development machines. You should see all the CTF/CTG files in your project directories with a long filename version. It has been reported however that some are missed. This has been raised and logged as an issue for Citect to investigate. If you have this issue then contact customer support as there is a tool that can automate saving the pages with long filenames. If the problem is not that large then a work-around is to open the relevant pages with Citect Graphics Builder and re-save them.

Other Things to note that will affect performance of IDC:

• The speed of the network. IDC can be used over links of varying speeds. If you have a slow link then the display client will be slow.

• The [Internet]UpdateTime parameter determines when CitectHMI/SCADA is forced to check to see if there is a newer version of the file regardless of whether the file is already existing in the client project area. When this timer expires it will go back to the internet cache to check on the currency of the files. You will see this for each page you navigate to until all the checks have been done.

IDC slow Internet Web Client