View trend charts
A trend chart displays data over time in a graphical format. Trend charts display values from tags in a controller, user-defined properties, or properties of a graphic element. If a tag exists in a configured data log, the trend chart also displays historical data. A trend chart can monitor tank pressure and tank temperature over the course of an hour.
View Designer
supports up to four trends per screen. Trend charts start updating when a screen containing the trend chart opens. The trend chart plots any available historical data. By default, trend charts collect and show data on traces every second. Updates occur even if there is no sample data to display for the current time span. Traces appear on a trend chart when there are two available data points. Trend charts are interactive. Pause trend chart data for closer inspection. Resume to continue updates to a trend chart. To view previous or more recent data, pan trend charts backward or forward.
Use a trend chart to:
- Monitor processes in a manufacturing system.
- Display data from a tag, user-defined property, or property of a graphic element. Tags may include historical data.
- Display up to eight traces that plot data over time to graphically present data.
- View, pan, and pause data on the HMI device.TIP:Tips:
- For applications already on the HMI device, it may take up to the length of the sample rate before data shows on the trend chart. If the trend chart has a sample rate of 30000 milliseconds or 30 seconds, it may take up to 30 seconds before any data shows on the trend chart. For applications downloading to the HMI device, it can take twice the sample rate to show data while establishing communication with the controllers.
- If there are multiple sets of data for the same time period in the data log, the trend chart plots only the most recent data for the time period. This occurs even if a previous set of data for the time period has more data than the most recent set of data.
- When both historical and real-time data is available, the trend chart shows real-time data at the sample rate of the trend chart. Historical data displays at the sample rate of the data log.
Provide Feedback