The following fields affect the time displayed in the chart when you use a fixed start time and date:
- Lock Time
- Time Zone (Historian only)
- Adjust for Daylight Savings Time (Proficy Historian only)
iFIX charts save time as Coordinated Universal Time (or UTC time). When you switch to the run-time environment, UTC time is read from the picture file containing the chart, and is then converted to local time before the chart fetches data from the historical file. Therefore, when you configure a chart, time is entered and displayed in local time. However, the time saved within the chart is in UTC time, which allows the data to be displayed independently of specific time zones.
The following examples help explain the concept of using time zones and daylight saving.
Example 1: No Features Enabled
In this example, pictures are created and saved in Eastern Standard Time (EST). The Fixed Time is set to 09:00:00, the Duration Before Now is set to 01:00:00, and Days Before now is set to 0. You get these results when you open the picture in the indicated time zone:
EST – displays data from 9:00 to 10:00 a.m.
CST – displays data from 8:00 a.m. to 9:00 a.m. local time.
Example 2: Lock Time Feature is Enabled
In this example, pictures are created and saved in EST. The Fixed Time is set to 09:00:00, the Lock Time is selected, the Duration Before Now is set to 01:00:00, and Days Before now is set to 0. You get these results when you open the picture in the indicated time zone:
EST – displays data from 9:00 to 10:00 a.m. local time.
CST – displays data from 9:00 a.m. to 10:00 a.m. local time.
Example 3: Developing for Remote Deployment (Proficy Historian only)
When you use the Time Zone and Adjust for Daylight Savings Time fields, the pictures you create are independent of the time zone in which you draw them. This independence gives you more control of the behavior of a picture when it is opened.
In this example, pictures are created and saved in EST, but deployed to a computer in Pacific Standard Time (PST). If you want the picture to show 9:00 a.m. to 10:00 a.m. PST when opened, you must select the explicit PST time zone in the Chart tab and set the start time to 9:00 a.m. You must also select Lock Time check box.
If your plant policy is to automatically adjust for Daylight Saving Time and you have selected Automatically Adjust for DST in the Control Panel time settings, then you should select the Adjust for Daylight Savings Time check box in Chart tab.
Example 4: Developing for Multiple Time Zone Deployment (Proficy Historian only)
You can share pictures across time zones by using the client time zone setting in the Chart tab.
In this example, pictures are created and saved in EST, but deployed to a computer in EST in the client time zone. The Lock Time is selected. When the picture is opened in CST, PST, or EST, it is always displayed as 9:00 a.m. local time.
Example 5: Using Server Time Zone (Proficy Historian only)
A picture configured to use the server time zone can be opened on any client machine in any time zone and will always show the same plot of data.
Example 6: Displaying Data from Other Time Zones (Proficy Historian only)
You are investigating an event that occurred at 3:30 Central Standard Time (CST) and your computer is in PST. Rather than open a chart with a 1:30 start time in PST, you can select the explicit central time from the Time Zone field and set the Fixed Time at 3:30
Example 7: Displaying Data from Multiple Time Zones (Proficy Historian only)
You have some points in the Proficy Historian archive that contain data from Mountain Standard Time (MST) and some from PST. You want to create a chart to display the events that occurred in each time zone at 10:00 a.m. Rather than being required to know the exact time zone location of each point and then choosing explicit time zones, you can select the tag time in the Time Zone field and set the Fixed Time at 10:00 a.m.
The UTC time feature of iFIX charts allows you to easily view and analyze a data plot, no matter where you display the data.
