Setting the Time Zone of a Real-Time Controller

This article explains the steps to follow to configure a Real-Time controller's time zone. It includes three different approaches to change the time zone depending on the application, the developer implementations and developer interests. 

After following the steps listed in this document, the controller's current time zone can be configured and correct time stamps in graphs, data structures and data logs can be obtained. 

By default, the Real-Time controller is set to Coordinated Universal Time (UTC). This can be configured differently using one of the following methods:

1. Using Measurement & Automation Explorer (MAX).
2. Modifying the INI file.
3. Using NI System Configuration APIs.

Measurement & Automation Explorer

Select the desired time zone in MAX on the Time Settings tab of the Real-Time target.

 

Modifying the INI File (for VxWorks or Phar Lap ETS Real-Time Targets only)

The following method is limited to Phar Lab and VxWorks based targets. If the device is running NI Linux RT, please follow the steps listed in NI Linux Real-Time Target Timezone Does Not Match Configured Timezone.

The time zone of a Real-Time controller can also be changed by modifying the RTTarget.TimeZone token in the ni-rt.ini file. The token can be found in the [LVRT] section of the file. 

Instructions on obtaining and modifying the INI file can be found below:

1. Use WebDAV or FTP to copy the ni-rt.ini file from the Real-Time controller to the development computer.
   • Follow Using WebDAV to Transfer Files to Real-Time Target or How Can I Transfer Files over FTP to a Remote System? for respective instructions.
2. Open the ni-rt.ini file in a text editor (for example Notepad).
3. At the top of the file, there is a section named [LVRT], which is where the RTTarget.TimeZone token may be found or added.
4. To change the time zone either add or modify the RTTarget.TimeZone token to the INI file.
   • For example, use INI token RTTarget.TimeZone=CST6CDT to set the controller to the Central United States time zone.
   • Other available INI values are listed in the table below:
      

     INI Value	Time Zone	UTC Offset
     CUT0GDT	Coordinated Universal Time	UTC
     GMT0BST	United Kingdom	UTC
     AZOREST1AZOREDT	Azores, Cape Verde	UTC-1
     FALKST2FALKDT	Falkland Islands	UTC-2
     GRNLNDST3GRNLNDDT	Greenland, East Brazil	UTC-3
     AST4ADT	Central Brazil	UTC-4
     EST5EDT	Eastern United States, Colombia	UTC-5
     CST6CDT	Central United States, Honduras	UTC-6
     MST7MDT	Mountain United States	UTC-7
     PST8PDT	Pacific United States, Yukon	UTC-8
     AST9ADT	Alaska	UTC-9
     HST10HDT	Hawaii, Aleutian Islands	UTC-10
     BST11BDT	Bering Strait	UTC-11
     NZST-12NZDT	New Zealand	UTC+12
     MET-11METDT	Solomon Islands	UTC+11
     EET-10EETDT	Eastern Australia	UTC+10
     JST-9JSTDT	Japan	UTC+9
     KORST-9KORDT	Korea	UTC+9
     WAUST-8WAUDT	Western Australia	UTC+8
     TAIST-8TAIDT	Taiwan	UTC+8
     THAIST-7THAIDT	Thailand	UTC+7
     TASHST-6TASHDT	Central Asia	UTC+6
     PAKST-5PAKDT	Pakistan	UTC+5
     WST-4WDT	Gorki, Central Asia, Oman	UTC+4
     MEST-3MEDT	Turkey	UTC+3
     SAUST-3SAUDT	Saudi Arabia	UTC+3
     WET-2WET	Finland	UTC+2
     USAST-2USADT	South Africa	UTC+2
     NFT-1DFT	Norway	UTC+1

5. Save the file as ni-rt.ini locally (such as the desktop).
6. Use WebDAV or FTP to transfer the file back to the Real-Time controller.
7. Reboot the Real-Time controller.

Note: Linux Real-Time targets support the tz (or Olson) database. The database contains all the needed information about DST settings for specific time zones. The RTTarget.DSTRule INI token cannot be changed to alter DST rules on Linux RT targets.

NI System Configuration APIs

LabVIEW 2012 Real-Time Module and later:
The LabVIEW 2012 Real-Time Module introduced the NI System Configuration API, which can be used to programmatically set the time zone of a Real-Time Controller using the Set Time VI.

The input Time Zone string for the Set Time VI needs to be of the form Etc/GMT-X where positive values for X represent hours west of the GMT. For example, Etc\GMT+6 is the equivalent to Central Standard Time in the US. Valid values range from 12 to -13 centered around GMT.

Note: This image is a LabVIEW snippet, which includes LabVIEW code that you can reuse in your project. To use a snippet, right-click the image, save it to your computer, and drag the file onto your LabVIEW diagram.

If the above code snippet is executed on the Real-Time target, the Target parameter must have a value of localhost. Otherwise, Error -2147467263 NI System Configuration: This operation is not implemented for this target or resource will be thrown.

LabVIEW 2011 Real-Time Module and Previous:
The LabVIEW 2011 Real-Time Module and previous Real-Time Modules do not include support for setting a specific time zone. Instead, it is recommended to set the time programmatically using the RT Set Date and Time VI.

Note: VxWorks and Pharlap targets must be restarted for the time zone settings to apply. NI Linux Real-Time targets do not require a restart. Configuring the time zone also activates the daylight saving feature of the controller.