PROT_81_OU
ANSI 81O/81U over and under-frequency stage with definite time, dropout hysteresis and an under-voltage block.
When to use it
Use PROT_81_OU when one frequency stage is needed on a generator or an interconnection — grid-code frequency protection, under-frequency load shedding, or an over-speed / under-speed supervisory trip.
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 | Unit |
|---|---|---|
| ENABLE | BOOL | — |
| FREQ | REAL | Hz |
| F_OK | BOOL | — |
| F_NOM | REAL | Hz |
| UF | REAL | Hz |
| OF_HZ | REAL | Hz |
| DELAY | TIME | — |
| HYST_HZ | REAL | Hz |
| V_PCT | REAL | % |
| V_BLOCK_PCT | REAL | % |
| BLK | BOOL | — |
| ACK | BOOL | — |
Outputs
| Port | Type | Unit |
|---|---|---|
| PICKUP | BOOL | — |
| PICKUP_UF | BOOL | — |
| PICKUP_OF | BOOL | — |
| TRIP | BOOL | — |
| TRIP_UF | BOOL | — |
| TRIP_OF | BOOL | — |
| F_DEV_HZ | REAL | Hz |
| BLOCKED | BOOL | — |
| V_BLOCKED | BOOL | — |
| ALM_MEAS_FAULT | BOOL | — |
| ALM_CFG_ERR | BOOL | — |
IEC 61499 event interface
EI INIT, REQ·EO INITO, CNF
Supervised control write
PROT_81_OU commands a real actuator. It is written to sit underneath your own interlock, permissive and protection logic — not to replace it. Commission it as you would any control block you wrote yourself.
Validation evidence
- Tests
- 8
- Simulated scans
- 96
- 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 PROT_81_OU — 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.