Applies To:
  • CitectSCADA 3.xx, 4.xx, 5.00

I am printing a trend with a large span time (eg. 19 hours for a 2 second trend) and the printout does not match the display. The printout seems to be shifted with the most recent data not displayed. I have investigated further and have found that the problem is with the data returned from TrnGetTable. Can large span displays be printed properly? 

There is a bug in the way the data is collected for large span trends. This does not affect the normal display of trends but will affect TrnGetTable and anything that uses TrnGetTable, like trend printing. The problem has to do with how the trend server handles requests that require interpolation across a large amount of data. This is done differently than for smaller amounts. The actual problem is that when the server is responding to such a request it does not set a return parameter correctly causing the problem.

A large span time is defined in the following way

Periodic Trends and SPC trends - 32000 times the sample period.

Event Trends and SPC Event Trends (TrnEventGetTable) - 5416 events

CIT has confirmed this to be a problem in Citect for Windows versions 3.00 to 5.00. This problem has been fixed in version 3.40/4.20 Service Pack J and version 5.00 Service Pack D.