Knowledge Base

Introduction

Alarm syntheses are used to create alarm counters for groups of alarms. For example, a counter of On and Not Acknowledged alarms. Each alarm synthesis can include a Server List which is used to decide on which station(s) the value of the counter is produced.

Populations are a filter which may be applied to the variables tree of a station to control the distribution of variable values. You can create populations from the menu Configure\Variables\Populations,  or using SCADA Basic (instruction POPULATION and STATION_FILTER)

Populations and Alarm Syntheses

When creating an alarm synthesis there is a setting Take the applied population into account. Depending on the configuration of the server list and this setting different behaviors will occur.

• LS ASSO – Server list containing an association of redundant servers. Only the active server calculates the synthesis.
• LS ALL – Server list containing all stations.
• LS N  – Server list with one or more servers. Only the servers in the list calculate the synthesis.

We assume a correct configuration where the synthesis result variables are produced by the same list as used by the alarm synthesis. Result variables can be consumed only in the case of the list LS ASSO. The setting Take the applied population into account can be ticked or not depending if you want to take into account the population of station that produces the synthesis.  There is also a difference if the station loads all variables (project  ALLVAR) or not (project NOALLVAR).

Case 1: The synthesis is calculated by the active server using its populations and variables.

Case 2: The synthesis is calculated by each station using its respective populations and variables. The result of the synthesis may be different on each station. For example, a server station calculates 20 alarms ONNOACK because the server loads all variables and has no population. A client station calculates 2 alarms because it does has not loaded all variables and has a population applied.

Case 3: The synthesis is calculated by each station in the list using its respective populations and variables. The result of the synthesis may be different on each station.

Case 4: The synthesis is calculated by the active server without taking into account any populations.

Case 5:  Forbidden.  It’s unnecessary to calculate synthesis of each station if you do not take into account the population when you have a station with all variables. Refer to case 4.

Case 6:  Forbidden. It’s unnecessary to calculate synthesis of each station if you do not take into account the population when you have a station with all variables. Refer to case 4.

Case 7: The synthesis is calculated by the active server without taking into account any populations.  Caution some client stations can receive a result that indicates the presence of alarms but alarms are not load by the client station.

Case 8: The synthesis is calculated by each station using its respective variables but  without taking into account any populations. The result of the synthesis may be different on each station.

Case 9: The synthesis is calculated by each station using its respective variables but  without taking into account any populations. The result of the synthesis may be different on each station.