WATCHDOG
Supervision timer — OK drops if KICK is not seen within TIMEOUT, and latches until acknowledged.
When to use it
Use WATCHDOG when a signal that should keep arriving might stop — a SCADA heartbeat, a remote skid's status word, a sensor that updates on change — and its absence must be treated as a fault rather than as a steady last value.
Interface
The published port signature. This is the whole of what the block exposes to your program — the implementation body is not shown here and ships with the download.
Inputs
| Port | Type |
|---|---|
| KICK | BOOL |
| TIMEOUT | TIME |
| ACK | BOOL |
Outputs
| Port | Type |
|---|---|
| OK | BOOL |
| EXPIRED | BOOL |
IEC 61499 event interface
EI INIT, REQ·EO INITO, CNF
Validation evidence
- Tests
- 5
- Simulated scans
- 85
- Simulator
- v0.1.0
Complete IEC 61131-3 implementation with a published test suite that runs on the vplant simulator. The counts above are that suite, executed on this build.
- Conforms to IEC 61131-3
- Conforms to IEC 61499
Download WATCHDOG — free
Create a free Ri Tech account to download the block. You get the Structured Text body, the Rockwell Add-On Instruction (.L5X), the Schneider Control Expert DFB (.XDB), PLCopen XML, the IEC 61499 function block type (.fbt) and the datasheet.
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Source is never published on this page. The implementation is released to a signed-in Ri Tech account — free of charge, but never anonymously.