Knowledge Base

From version 9.0 SP1, the value displayed form an alarm variable, in a variable selector, is the alarm value. It no longer corresponds directly to the bit value read from the equipment.

The only way to display the actual bit value is to use “Bit Value” animation. But be careful, for an alarm that has been configured to be set when corresponding PLC bit is reset, the alarm value representation will be opposite to the bit value coming from the equipment. In this case, Alarm value = 1 could mean On Ack or OnNotAck  and Alarm Value = 0 could mean as well OffAck or OffNotAck

Warning:

In SCADA Basic, We use the bit value as described in the sample below:

int.ala0.0 is an alarm when bit value is set
int.ala0.1 is an alarm when bit value is reset

Sub Ala1()
If ( @int.ala0.0 == 0 ) Then
@int.text0.0 = “Alarm Off val=0”;
Else
@int.text0.0 = “Alarm On val=1”;
End If
End Sub

Sub Ala0()
If ( @int.ala0.1 == 0 ) Then
@int.text0.1 = “Alarm On val=0”;
Else
@int.text0.1 = “Alarm Off val=1”;
End If
End Sub

When int.ala0.0 = 1, we have @int.text0.0 = “Alarm On val=1”;  and the alarm is On
When int.ala0.1 = 1, we  have @int.text0.1 = “Alarm Off val=1”; and the alarm is Off

Note:

The preferred method is to use ALARM mode VALUE.

ALARM(“VALUE”,”Alarm_Name”);

Which returns the following values.

0 –> OffAck
1 –> OnNoAck
2 –> OffNoAck
3 –> OnAck
4 –> NS