Applies To:
  • CitectSCADA 4.20 Service Pack D
Summary:
Citect version 3.x periodic trend files format needs to be converted to that of version 4.x and 5.x.

Solution:
This conversion is achieved by updating the start time and end time of the trend history files. These times reside in the header of the history files. The master trend file (.HST) is also updated to be the same as the history files. This conversion takes place at the start up of the trend server provided that the parameters shown below are set:

[TREND]
ConvertTime =
0 (Do not do time conversion - DEFAULT)
1 (Do time conversion)

[TREND]
TimeZone =
The timezone in minutes. This time will be different depending on whether the conversion time is in Standard Time or Dayligt Saving Time.

For example,
for Sydney TimeZone = 600 (10 hours) (if conversion time is in Standard Time)
= 660 (11 hours) (if conversion time is in Daylight Saving Time)
for West Coast USA = -480 (-8 hours) (note the minus sign) (Standard Time)

If convert time is set then all trend history files (including the master file) will be updated to have the correct time. At the end of conversion Citect will shutdown and reset the [TREND]ConvertTime parameter so that the next start up will not do the time conversion IMPORTANT NOTE:

Make sure that you have backed up your trend files before this conversion in order to start the conversion afresh in case an error occurs during the conversion process. This conversion applies only to the periodic and periodic-event type trends. (Periodic-event type trends are stored in the history files as the periodic trends are). Event type trend's time is not converted.

 
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