flowchart TD
A[Start] --> B{Active alarm?}
B -->|Yes| C[Notify HMI]
B -->|No| D[Monitor]
C --> E{Acknowledged?}
E -->|Yes| D
E -->|No| C
D --> B
sequenceDiagram
Actor Op as Alarm
Op->>Bit: Alarm triggered
Bit->>Group: Notify alarm
Group->>Super: Propagate alarm
Super->>Global: Propagate alarm
classDiagram
class FB_AbstractAlarmData {
<<abstract>>
+BOOL bEnable
+INT iLevel
+Run()*
+Reset()*
}
class FB_AlarmBit {
+BOOL bInput
+Run()
+Reset()
}
class FB_AlarmBitWithOM {
+BOOL bOM
+Run()
+Reset()
}
FB_AbstractAlarmData <|-- FB_AlarmBit
FB_AbstractAlarmData <|-- FB_AlarmBitWithOM
stateDiagram-v2
[*] --> Inactive
Inactive --> Active : Condition detected
Active --> Acknowledged : Operator ACK
Acknowledged --> Inactive : Condition resolved
Active --> Inactive : Forced reset
Acknowledged --> Active : Condition persists
erDiagram
GROUP ||--o{ OBJECT : contains
OBJECT ||--o{ ALARM : generates
ALARM {
int id
string message
int level
datetime timestamp
}
OBJECT {
int id
string name
string description
}
GROUP {
int id
string name
}
gantt
title Alarm implementation planning
dateFormat YYYY-MM-DD
section Design
Define hierarchy :done, d1, 2026-01-01, 7d
Define levels :done, d2, after d1, 5d
section Development
FB_AlarmBit :active, a1, 2026-01-13, 10d
FB_AlarmBitWithOM : a2, after a1, 10d
Trace system : a3, after a2, 14d
section Testing
Unit test : t1, after a3, 7d
Integration test : t2, after t1, 7d
pie title Alarm distribution by level
"Critical" : 15
"High" : 28
"Medium" : 40
"Low" : 17
gitGraph
commit id: "Init"
branch develop
checkout develop
commit id: "FB_AlarmBit"
commit id: "FB_AlarmBitWithOM"
branch feature/trace
checkout feature/trace
commit id: "Trace v1"
commit id: "Trace v2"
checkout develop
merge feature/trace
checkout main
merge develop id: "Release 1.0"
mindmap
root((PLC Alarms))
Types
AlarmBit
AlarmBitWithOM
AlarmBitForSafety
Levels
Critical
High
Medium
Low
Tracing
Group
Object
Alarm
HMI
Visualization
Acknowledgment
History
timeline
title Alarm module history
2023 : Initial version
: Basic FB_AlarmBit
2024 : FB_AlarmBitWithOM
: Multilingual support
2025 : FB_AlarmBitForSafety
: Trace system
2026 : Advanced HMI integration
: Trace v2
journey
title Alarm lifecycle
section Detection
Condition active: 5: PLC
Generate alarm: 5: FB_AlarmBit
section Notification
Send to HMI: 4: PLC
Show to operator: 3: HMI
section Resolution
Review cause: 2: Operator
Acknowledge alarm: 4: Operator, HMI
Resolve condition: 3: Operator
Clear alarm: 5: PLC, HMI
quadrantChart
title Alarms by frequency vs impact
x-axis Low frequency --> High frequency
y-axis Low impact --> High impact
quadrant-1 "Critical"
quadrant-2 Annoying
quadrant-3 Ignore
quadrant-4 Monitor
Motor fault: [0.8, 0.9]
"Low pressure": [0.6, 0.7]
Temperature: [0.5, 0.4]
Door open: [0.3, 0.2]
Low level: [0.7, 0.5]
requirementDiagram
requirement req_alarm {
id: 1
text: The system must generate alarms in less than 100ms
risk: high
verifymethod: test
}
requirement req_ack {
id: 2
text: The operator must be able to acknowledge alarms from HMI
risk: medium
verifymethod: demonstration
}
element FB_AlarmBit {
type: component
}
FB_AlarmBit - satisfies -> req_alarm
FB_AlarmBit - satisfies -> req_ack
block-beta
columns 4
Input:1 space:1 Output:1
space
PLC["PLC S7-1x00"]:3
space:2
_alarmBit:3
space:2
_trace:3
space
_hmi:3
Input --> PLC
PLC --> Output
PLC --> _alarmBit
_alarmBit --> _trace
_trace --> _hmi
xychart-beta
title "Alarms per hour"
x-axis ["00h","02h","04h","06h","08h","10h","12h","14h","16h","18h","20h","22h"]
y-axis "Number of alarms" 0 --> 50
bar [5, 3, 2, 4, 12, 28, 45, 38, 42, 30, 15, 8]
line [5, 3, 2, 4, 12, 28, 45, 38, 42, 30, 15, 8] 