SEAMLESS_TRANSITION
Planned island hand-off supervisor: proves the pre-conditions, issues the open, and measures and certifies the transition.
When to use it
Use SEAMLESS_TRANSITION when an intentional island has to be taken without dropping load, and somebody has to prove afterwards — with a number, not an opinion — how long the bus was between voltage sources.
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 | — |
| START | BOOL | — |
| ABORT | BOOL | — |
| GFM_RDY | BOOL | — |
| GFM_ACTIVE | BOOL | — |
| TIE_AT_ZERO | BOOL | — |
| PCC_CLOSED | BOOL | — |
| FREQ_DEV | REAL | Hz |
| FREQ_DEV_MAX | REAL | Hz |
| MAX_TRANS_MS | REAL | ms |
| PREP_TMO | TIME | — |
| SETTLE_TMO | TIME | — |
| TRANS_MS_EXT | REAL | ms |
| EXT_OK | BOOL | — |
| ACK | BOOL | — |
Outputs
| Port | Type | Unit |
|---|---|---|
| TRANS_MS | REAL | ms |
| STATE | USINT | — |
| PREP_REQ | BOOL | — |
| OPEN_CMD | BOOL | — |
| DONE | BOOL | — |
| TRANS_OK | BOOL | — |
| SCAN_LIMITED | BOOL | — |
| ALM_TRANS_FAIL | BOOL | — |
| ALM_FREQ_DEV | BOOL | — |
| ALM_CFG_ERR | BOOL | — |
IEC 61499 event interface
EI INIT, REQ·EO INITO, CNF
Supervised control write
SEAMLESS_TRANSITION 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
- 9
- Simulated scans
- 101
- 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 SEAMLESS_TRANSITION — 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.