PROT_49_THERM
ANSI 49 thermal replica to IEC 60255-149: exponential heating and cooling on a declared time constant, with alarm, time-to-trip and a restart inhibit.
When to use it
Use PROT_49_THERM when a machine, cable or transformer needs overload protection whose memory reflects the thermal state of the plant rather than the duration of the present overload — the case wherever repeated or cyclic overloads occur and an overcurrent curve would forget between them.
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 | — |
| I | REAL | A |
| I_OK | BOOL | — |
| I_NOM | REAL | A |
| TAU | TIME | — |
| K_FACTOR | REAL | pu |
| ALM_PCT | REAL | % |
| TAU_COOL_MULT | REAL | pu |
| RESET_PCT | REAL | % |
| BLK | BOOL | — |
| ACK | BOOL | — |
Outputs
| Port | Type | Unit |
|---|---|---|
| THETA_PCT | REAL | % |
| TRIP | BOOL | — |
| ALARM | BOOL | — |
| INHIBIT | BOOL | — |
| T_TRIP | TIME | — |
| T_TRIP_VALID | BOOL | — |
| THETA_FINAL_PCT | REAL | % |
| BLOCKED | BOOL | — |
| ALM_MEAS_FAULT | BOOL | — |
| ALM_CFG_ERR | BOOL | — |
IEC 61499 event interface
EI INIT, REQ·EO INITO, CNF
Supervised control write
PROT_49_THERM 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
- 10
- Simulated scans
- 1638
- 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_49_THERM — 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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