Hierarchies In Alarms

Contents

• Hierarchies In Alarms
  • TOP/BOTTOM
  • Alarm GROUP
    • Future Releases

TOP/BOTTOM

The TOP/BOTTOM just provides a filter for finding alarms where the value of another alarm is used directly in the formula. It is case sensitive, so you can use lower/upper case to show/hide alarms in these filters.

To use hierarchies, alarms shall be written using the result of previous ones:

GAB1 = any([t >5 for t in FIND(tc1:10000/LMC/C01/GAB/*)])
GAB2 = any([t >5 for t in FIND(tc1:10000/LMC/C02/GAB/*)])
GAB_ALL= GAB1 or GAB2
OTHER = tc1:10000/LMC/C02/Other/State != ON
CAPITAL = GAB_ALL or OTHER

Then, the filter by hierarchy will return:

TOP (alarms that depend on others): CAPITAL, GAB12
BOTTOM (alarms isolated or referenced from others): OTHER, GAB_ALL, GAB1, GAB2

In this case GAB_ALL appears in both lists; to avoid that just rewrite it using lower case attribute names:

GAB_ALL = any(FIND('lmc1:10000/lmc/alarms/01/gab*'))

Now you should have only “CAPITAL” as TOP Alarm.

You can reproduce this behaviour from the api calling:

panic.AlarmAPI().filter_hierarchy('TOP')

Alarm GROUP

For an expression matching multiple alarms or attributes, GROUP returns a new formula that will evaluate to True if any of the alarm changes to active state (.delta) or matches a given condition:

GROUP(ALARM1, ALARM2, ALARM3)

Thus, GROUP will be activated when any of the three alarms switches to active; and immediately reset to wait for the next change. In this way you get a notification for any new activation of the three alarms.

NOTE: BY DEFAULT IS NOT LIKE any(FIND(*)); it will react only on change, not taking in account previous states!

NOTE2: you must tune your PyAlarm properties to have AlarmThreshold = 1 and AutoReset <= 3 to take profit of this feature.

NOTE3: The GROUP activation will be just a peak when using .delta (default); take this in account when setting up several levels of alarms as fast peaks may not be noticed if higher level alarms have long thresholds.

It uses the read_attribute schema from TangoEval, thus using .delta to keep track of which values has changed. For example, GROUP(test/alarms/*/TEST_[ABC]) will be replaced by:

any([t.delta>0 for d in FIND(test/alarms/*/TEST_[ABC].all)])

But, as regular expressions may trigger unexpected results, the syntax with explicit ALARM names is prefered.

The GROUP macro can be called with one or several expressions separated by commas and a condition separated by semicolon:

GROUP(expression1[,expression2;condition)

Expressions may contain a device name or not. If no device name is passed then it will search for it in the alarm list:

expression=[a/dev/name*/]attribute*

Thus, a valid GROUP expression is:

GROUP(LOCAL_ALARM1,t01:10000/an/alarm/dev/ALARM2)

Or

GROUP(LOCAL_ALARM1,t01:10000/an/alarm/dev/ALARM2;x>=1)

In the first case you’ll get a peak when any of them changes from 0 to 1; in the second case you’ll get if any of them is already on 1 (so a change in the second alarm will not trigger a second peak).

Future Releases

In future releases the GROUP macro will be capable of evaluating any tango attribute and not only alarms. As of 6.0 this feature is not yet supported

If the condition is empty then PyAlarm checks any .delta != 0. It can be modified if the formula contains a semicolon “;” and a condition using ‘x’ as variable; in this case it will be used instead of delta to check for alarm:

GROUP(bl09/vc/vgct-*/p[12];x>1e-5) => [x>1e-5 for x in FIND(bl09/vc/vgct-*/p[12])]