Applies To:
  • CitectSCADA 1.00 1.01 1.10 1.11 1.20 2.00 2.01 3.00 4.10

Are there Timezone parameters in Windows for Workgroups like in Windows 95 and Windows NT? 

Yes, contrary to popular belief there is indeed a timezone parameter in Windows for Workgroups. It is the DOS environment variable TZ. It is set by default to Pacific Standard Time (West Coast of America, no doubt because the programmer who wrote the code lives in this time zone). Normally programs don't take Timezones into consideration under Windows for Workgroups, however Citect does. If you are considering upgrading to 32 bit Citect in the future or mixing 16 bit and 32 bit Citects on a network then you should be currently running 16 bit Citects with this parameter set correctly. This will mean that your Trend History files will be compatible with 32 bit versions of Citect and time transfer between 16 bit and 32 bit Citects will be correct.

To set the TZ variable use the following syntax in your Autoexec.bat file.

SET TZ=ABC[+-]hh[:mm[:ss]]


ABC is an arbitrary 3 letter timezone name
hh[:mm[:ss]] is the timezone difference in hours[minutes[seconds]] (note: west of Greenwich is positive)

For example. To set the TZ variable for Sydney, Australia which is 10 hours EAST of Greenwich the syntax would be

SET TZ=EST-10 (Note: EST is arbitrary. East of Greenwich is negative)


  1. If you don't ever intend upgrading then the default of Pacific Standard time is okay.
  2. If you have existing Trend History files and you set the TZ variable you will need to upgrade them.