An alarm only tag can only be used for its alarm by the alarm system.
An alarm only tag:
No code or animation can read or write the value of an alarm only tag.
The advantage of using alarm only tags is their low cost for licence I/O tag count.
Indeed an alarm only tag count only an 1/8th of an I/O tag for licence limitation.
So an alarm collecting/recording JSup application would be very cheap, because every 8 alarm only tags only one I/O tag is counted for licence I/O limitation.
