Multi-digital alarms use the output from three digital variables (for example: tags A, B, and C) to define eight states. The states represent every possible combination of true/false values the variables can have.
The tag values in each state are represented in the order tag C, tag B, tag A. A true value is represented by the tag letter, and 0 (zero) represents false.
The eight states are as follows:
When configuring the multi-digital alarm properties, you can set which states will trigger an alarm, and specify Cicode functions to be called when alarms become active and inactive.
The variables configured for a multi-digital alarm are polled at the rate set by the Citect.ini parameter [Alarm]ScanTime. If an alarm state changes, notification will occur the next time the variables are polled. The time associated with the alarm state will represent the time the variable was polled, not the actual time the alarm condition occurred.
Examples
In the following example, tag C is left blank, and the variables BIT_12 and BIT_1 are specified for tags A and B. With state 0BA specified to activate an alarm, when tags A and B change to ON (1) the alarm will activate.
|
Var Tag A |
BIT_12 |
|
Var Tag B |
BIT_1 |
|
Var Tag C |
In this example, variables are specified for the three tags. If state CBA is specified to activate an alarm, when the three variables change to ON (1) the alarm will activate.
|
Var Tag A |
RFP3_TOL |
|
Var Tag B |
BIT_1 |
|
Var Tag C |
MCOL_304 |
To configure a multi-digital alarm:
See Also