AlarmNotifyVarChange
This function is used to provide time-stamped digital and time-stamped analog alarms with data. When called, it notifies the alarm server that the specified variable tag has changed.
The alarm server will then check all time-stamped digital and time-stamped analog alarms that use the variable tag to see if their alarm states need to be updated as a result of the change. Any alarm state changes that result from this check will be given the timestamp passed into this function as their time of occurrence.
Note: Although you can hardcode a value into the setpoint when using analog alarms, you cannot use hardcoded values with time-stamped analog alarms. If the setpoint is hardcoded, this function cannot be used to notify the alarm when the variable changes.
Syntax
AlarmNotifyVarChange(Tag, Value, Timestamp [, TimestampMS] [, ClusterName] )
Tag:
Name of the variable tag that has changed as a string. This name may include the name of the tag's cluster in the form cluster.tagname. This cluster name may be different from the cluster of the alarm server indicated by ClusterName below.
The Tag parameter is resolved on the alarm server, so the alarm server should be configured to connect to the tag's cluster.
Value:
Value of the variable tag at the time of the change as a floating-point number
Timestamp:
Time/date at which the variable tag changed in the standard CitectSCADA time/date variable format (Seconds since 1970).
TimestampMS:
Millisecond portion of the time at which the variable tag changed.
ClusterName:
Name of the cluster of the alarm server. This is optional if you have one cluster or are resolving the alarm server via the current cluster context. The argument is enclosed in quotation marks "".
Return Value
The error that was detected when the function was called.
Example
AlarmNotifyVarChange("LOOP_1_SP", 50.0, TimeCurrent() - 10, 550,
"ClusterXYZ");
This will tell the alarm server in cluster XYZ that the value of
variable tag LOOP_1_SP changed to 50.0 at 9.450 seconds ago.
See Also
Time-stamped Digital Alarm Properties, Time-stamped Analog Alarm Properties