Time-Based Chart
A time-based chart displays a bar every time the specified time interval ends. You can have a 20-second chart, 5-minute chart, 30-minute chart, daily chart, weekly chart, etc. In each case, the open, high, low, and closing prices for that time period are recorded in each bar.
For example, in a chart with a 30-minute data interval, one bar on the chart represents the open, high, low, and closing prices of all the transactions that occurred within that 30-minute period. The number of ticks in that 30-minute period could be 1, 112, or 10,000; it doesn't matter - the bar displays the open, high, low and closing prices for the 30-minute period. In a time-based data interval, the number of ticks recorded in each period is of no relevance and is not represented in the bar.
For a description of the
different chart types available, see Chart Types.
When you use an intra-day time-based data interval (an interval less than a day, and based on time), you can create bar charts using 30-second bars, 1-minute bars, 10-minute bars, or any time increment you want to see during the trading day.