The BAR widget graphically displays numeric values using a single bar.
If your computer has a monochrome monitor, the BAR widget will handle the situation automatically. There are no attributes related to color to set for that special case. If you have a monochrome monitor, you will automatically get a frame around the BAR.
A frame consists of an outline around the BAR and lines at the LOW LIMIT and HIGH LIMIT values. The frame pen will be the inverse of the background pen. The background pen and the BAR pen will be the same. For information on creating composite bar displays, see the BARS widget.
The bar size is controlled by writes to the VALUE attribute. The BARwidget does not operate independently. You must write VALUEs to the widget. An event can be generated on any or all of the three ranges: "LOW", "MIDDLE", or "HIGH".
BAR widget events are level-triggered, not edge-triggered. An event is generated any time a VALUE is within the designated ALARM RANGE,not only when the VALUE transitions from one range to the other. You must specifically set the ALARM TYPE to event before an event can be generated. Otherwise, only beeps are generated.
Events
Events for the BAR widget are:
·
ALARM
·
SYSTEM MENU
ALARM
This event is generated when the VALUE attribute is set to a value within one of the ranges named in the ALARM RANGES attribute and the ALARM TYPE is "EVENT". The only time an ALARM event is generated is when the value of VALUE is set to one, several, or all of the following:
·
To or above HIGH LIMIT and the value of ALARM RANGES is "HIGH".
·
Between LOW LIMIT and HIGH LIMIT and the value of ALARM RANGES
is "MIDDLE".
·
To or below LOW LIMIT and the value of ALARM RANGES is "LOW".
Redraw activities, such as changing the ORIENTATION attribute value, will not generate an ALARM event.
SYSTEM MENU
This event is generated when the operator selects items from the SYSTEM MENU.