Since the first NiagaraAX release, platform configuration of a NiagaraAX host includes the setting of date and time, which includes specifying its local time zone. Typically, this is done using either a platform connection and the Platform Administration view (function “Change Date/Time”), or possibly after a station is installed and running, using the one of the station’s PlatformServices views (“Platform Service Container Plugin” or “System Date and Time Editor”).

Time zones appear on the selection list using a “Zone ID (hours UTC offset/hours [DST + UST] offset)” format. Some examples:

America/Chicago (-6,-5)

Europe/Berlin (+1,+2)

Asia/Tokyo (+9) 

Note there is no DST observance in Japan, so the selection with zone ID “Asia/Tokyo” shows only the UTC offset of +9 hours.

This selection list of available time zones is from a “time zone database” that resides on that host. For any host running AX-3.3 or later, this is a “historical database”, sourced in the file !lib/timezones.jar.

In this database, a history of changes for applicable time zones are stored, such that multiple definitions for a time zone may exist, including past definitions as well as its current definition. Time zones in this database are not user editable. However, this time zone database offers advantages for NiagaraAX jobs where accrued histories or alarms have spanned across different time zone definition eras. For more details, see About the historical time zone database.

Host platforms running pre-AX-3.3 builds use a !lib/timezones.xml file instead. In this database file, for each known time zone there is one definition, starting with its zone ID. If necessary, you can edit the definition of one or more time zones in this timezones.xml file (or replace with an edited version of this file). Note allthough AX-3.3 or later hosts also have a timezones.xml file, it is not used locally. See the section timezones.xml for more details.