Strip Chart is a tool for displaying streaming data in time history plots.
- A new Strip Chart window is created in the workbench with menu "Devices - Strip Chart".
- Strip Chart can also be executed detached from the workbench using the command line option "-strp".
The Strip Chart window is composed by two tabs:
- Config : allows configuring the data sources and the chart properties. Configuration can be saved and loaded with "Save" and "Open" buttons.
- Plot : holds the time history plots.
There are some startup options specific for Strip Chart when detached:
| Option | Description |
|---|---|
| -f=<...> | Open a StripChart configuration file (.scd). |
| -config=<...> | JSON configuration string (as in .scd file) or list of channel names. |
| -start | Start the data displaying immediately. |
| -v | Create a StripChart server. |
| -attach | Shared mode: try connecting to existing server, or create one if not available. |
| -background_color=<...> | Set default plot background color. |
| -grid_color=<...> | Set default plot grid color. |
| -tick_label_font=name:size | Set font for time plot tick labels. |
| -alarm_interval=<...> | Set the alarm timer interval (default 1000ms). |
| -alarm_file=<...> | Set alarm sound file (default use system beep). |
Note: The general startup options also apply, see document Startup Options.
The Series table holds the definition of the streamed data. Each series must be assigned to a Y axis of one of the five available charts. After the plotting starts, the series properties cannot change dynamically, with the exception of "Color" and "Alarm".
Column Description Enable Enables/Disables plotting. Name The name of the data source and type-specific optional parameters (see below). Type The type of data source: EPICS channel, BSREAD stream, Device or CamServer stream. Plot Plot number for this series (1-5). YAxis Y axis for this series (1-2). Color Color for the series. Alarm Enables alarm for the series, opening a window for setting alarm limits. The optional parameters depend on the type of data. The values on the Name column are formed by:
- A mandatory name.
- An optional list of values corresponding to type-specific parameters.
- An optional alias, surrounded by the delimiters: < >. If defined, if will be used in the plot legends instead of the full name.
Data Type Name and Optional Parameters Channel ChannelName [Polling(ms)=-1 Precision=-1] <Alias> CamServer uses EPICS channel monitors by default. If the data volume is to big for the the plotting, it can be lowered by specifying the Polling parameter. Instead of appending to the chart on the monitor event, the channel will be read in the given interval (in milliseconds.) Stream ChannelName [Modulo=1 Offset=0] <Alias> Stream data source are BSREAD channels requested to the Dispatcher. All Streams sources in a plot are aligned to the same pulse ID. Device DeviceName <Alias> Where DeviceName can be:
- A global device.
- An inline device string, as defined in Devices document, section Inline devices.
- A statement, if the interpreter is enabled (e.g. for accessing sub-devices).CamServer InstanceName ChannelName <Alias> - Alternativelly, the CamServer stream URL can be provided instead of the instance name.
The Charts table holds properties of each chart. Up to 5 charts can be used in Strip Chart. Each chart can have two Y axis (Y1 and Y2). After the plotting starts, the chart properties can be changed dynamically, with the exception of "Local Time".
Column Description Y1min, Y1max If both are specified, sets a fixed Y1 range (otherwise range is automatic). Y1max, Y2max If both are specified, sets a fixed Y2 range (otherwise range is automatic). Duration The time window of each history plot (default 60s). Markers If set, plots the markers of each data point over the series line. Local Time If set, adds data points based on the computer local time, instead of the channel time.
The Background and Grid buttons allow configuring the chart colors for background and grid. The Defaults button restores default values, which depend on the look and feel.
The spinner Plot Update configures, in milliseconds, how long data events are buffered before sent to the plots (default is 100ms).
The field Stream filter can hold an expression to filter stream data. An expression consist of condition on a channel, or a set of conditions separated by 'AND':
C1 [ AND C2 ] [ AND C3 ]...Each conditions if formed with a stream channel name, an operator and a value:
<channel name> <operator> <value>
The valid operators are: == , !=, <, >, <= or >=.
The values can be numeric, boolean ('true' or 'false'), or else a string (surrounded by quotes).
The spinner Drag Interval configures, in milliseconds, the time charts are scrolled if no new data is received (default is 1000ms).
If the checkbox Save to is checked then all received data is saved using the file name template and the given data format and layout (see document Data).
If the checkbox is not set before starting the plotting then, while plotting, it is replaced by a Save button, which saves the data currently displayed using the file name template and the given data format and layout.
After the configuration is done, acquisition and plotting starts by clicking the "Start" button - or simply by switching to the "Plots" panel.
Acquisition can be paused/resumed with the pause button in the to top right corner.
If an alarm is set and active, the relative chart will flash and a beep will sound every second. When alarming, a button displayed on the side of the Pause button silences the beep for 30 minutes.
The chart's context menu allows:
- Saving snapshots.
- Setting plot attributes.
- Changing the visibility of the series.
If the duration time is big and the sampling interval too small then plotting can get sluggish due to the lack of memory. In this case one can:
- Configure a bigger heap size for Java.
- Subsample the data using:
- Polling parameter for EPICS channels.
- Modulo parameter for BSREAD channels.