Playback
Playback replays a past period on the whole PI Vision display. It moves the display time range forward in steps, so every symbol that follows the display time shows how the process developed.
Overview
When to use it
Use Playback when you need to:
- Review how a process developed during an incident, to find the root cause.
- Walk a shift handover or a training session through a past period.
- Watch all trends and values on a display move together instead of reading one fixed range.
Use the PI Vision time bar instead when you only need to look at one fixed range.
Before you begin
- Open the display you want to review.
- Know the start and end of the period.
- Check that the symbols follow the display time range. A symbol with its own time range does not move during playback.
- If the Playback icon is missing from the side bar, an administrator has turned the tool off.
Common tasks
Replay the display range
Use this when the display already shows the period you want to review.
- In the PI Vision time bar, set the period, for example 8:00 PM to 11:00 PM.
- Select Playback in the side bar. The pane opens.
- Check Start (1). If you changed the display range after the pane opened, select Reset to Display Time (2).
- Select Play (3).
The display now shows the Display Span that ends at the playback position, and the position moves forward one Step Size at a time. The time above the slider and the time bar show where you are.
Replay a past period in your own steps
Use this to review a period other than the display range, or to change how much the display shows and how fast it moves.
- Select Playback in the side bar.
- Set Display Span (1) to the amount of time the display shows at once, for example 1 Hours.
- Set Step Size (2), for example 10 Minutes.
- Set Step Interval (3), the seconds between two steps.
- Enter Start (4) and End (5) of the period.
- Select Go to Start, then Play.
The display shows the hour that ends at 8:30 PM, then the hour that ends at 8:40 PM, and so on until the position reaches 10:30 PM. Choose a Step Size that is not larger than Display Span, or parts of the period are skipped.
Step through the replay by hand
Use this to stop at the moment something changed and look at it.
- Select Pause if the replay is running.
- Select Step Forward (4) or Step Back (3), or press the right or left arrow key.
- Drag the slider (1) to jump to another position.
- Select Go to Start (2) or Go to End (5) to jump to the first or last position.
Each step moves the display by one Step Size and never leaves the period between Start and End.
Repeat the replay in a loop
Use this for a training screen or a wall display that should keep running.
- Select Toggle Loop (1). The icon turns blue.
- Select Play (2). It turns into Pause while the replay runs.
When the position passes End, the replay starts again at Start. Select Toggle Loop again to stop looping. Without the loop, the replay stops at End.
Use the tool
| What it shows | |
|---|---|
| (1) | The Playback icon. It shows * while a replay runs. |
| (2) | The playback position. It is the end of the time range the display shows. |
| (3) | The slider between the Start and End times. |
| (4) | Go to Start, Step Back, Play or Pause, Step Forward and Go to End. |
| (5) | Toggle Loop. It is blue when the loop is on. |
| (6) | The Configuration settings. |
- Keyboard: Press the right arrow to step forward, the left arrow to step back, and the spacebar to play or pause. The keys work only while the pane is open and no text field has the focus.
- Playback changes the display time range for the whole display. It does not write data. Set the range back with the time bar when you are done.
- When you change the time yourself, for example with the time bar or by zooming or panning a trend, playback pauses and takes the new end of the display as its position. Select Play to continue from there.
- At the end, the replay stops at End. Play then starts again at Start.
- Nothing is saved. The settings live in the open page. Reloading the display resets them to the display range.
Configure the tool
The settings are in the Configuration section of the pane. The tool takes its first values from the display range: Start and End are that range, Display Span is one eighth of it, and Step Size is one fifth of the span.
| Setting | What it does |
|---|---|
| Display Span | The time range the display shows at each position. Choose a number and a unit from Seconds to Years. Used in Replay a past period. |
| Step Size | How far the position moves with each step. Choose a number and a unit from Seconds to Years. Use a step smaller than the span when neighboring views should overlap. |
| Step Interval | The seconds between two automatic steps. A smaller value plays faster. Default 2. |
| Start, End | The first and last position of the replay, entered as date and time. |
| Reset to Display Time | Sets Start, End, Display Span and Step Size from the current display range. |
The controls above the settings:
| Control | What it does |
|---|---|
| Slider | Moves to any position between Start and End and pauses a running replay. |
| Go to Start, Go to End | Jump to Start or End. |
| Step Back, Step Forward | Move one Step Size. Shortcuts: left and right arrow. |
| Play, Pause | Start or pause the replay. Shortcut: spacebar. |
| Toggle Loop | Restarts at Start after End. See Repeat the replay in a loop. |
Troubleshooting and limitations
| Symptom | Cause | What to do |
|---|---|---|
| The replay stops when you use the time bar or zoom a trend. | Playback pauses when the time changes from somewhere else. | Select Play to continue from the new position. |
| Changes pass too quickly. | Step Interval is short or Step Size is large. | Increase Step Interval or reduce Step Size. |
| Parts of the period are skipped. | Step Size is larger than Display Span. | Set Step Size equal to or smaller than Display Span. |
| Reset to Display Time gives unexpected values. | It reads the display range as it is now, and playback has moved it. | Set the period in the time bar first, then select Reset to Display Time. |
| Play does not move the display. | Step Size is empty or 0, or End is not after Start. | Enter a Step Size above 0 and check Start and End. |
| The arrow keys and spacebar do nothing. | The pane is closed, or a text field has the focus. | Open the pane and click an empty part of it. |
| A symbol does not change during playback. | The symbol has its own time range. | Set the symbol to follow the display time range. |
Limitation: The settings are not saved with the display. Playback has no speed setting other than Step Size and Step Interval.
