RTU_CTRL
Packaged rooftop unit — staged DX cooling and heating on zone temperature, with an integrated economiser and compressor anti-short-cycle protection.
When to use it
Use RTU_CTRL when a packaged single-zone rooftop unit with one to eight stages of DX cooling and one to eight stages of heating serves a zone from a zone thermostat, with or without an economiser damper.
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 | — |
| OCC | BOOL | — |
| ZONE_TEMP | REAL | °C |
| ZONE_SP | REAL | °C |
| ZONE_OK | BOOL | — |
| OA_TEMP | REAL | °C |
| OA_OK | BOOL | — |
| DB_K | REAL | K |
| STAGE_DIFF_K | REAL | K |
| STAGE_HYST_K | REAL | K |
| CLG_STAGES | USINT | — |
| HTG_STAGES | USINT | — |
| STAGE_ON_DLY | TIME | — |
| STAGE_OFF_DLY | TIME | — |
| MIN_OFF | TIME | — |
| ECON_HI_LIM | REAL | °C |
| ECON_LOW_LIM | REAL | °C |
| ECON_DB_K | REAL | K |
| ECON_PB_K | REAL | K |
| MIN_OA_PCT | REAL | % |
| FAN_ON_UNOCC | BOOL | — |
| CAP_TMO | TIME | — |
| ACK | BOOL | — |
Outputs
| Port | Type | Unit |
|---|---|---|
| CLG_STAGE | USINT | — |
| HTG_STAGE | USINT | — |
| SF | BOOL | — |
| ECON_DMPR | REAL | % |
| ECON_ACTIVE | BOOL | — |
| ZONE_ERR | REAL | K |
| MECH_LOCKOUT | BOOL | — |
| VALID | BOOL | — |
| ALM_ZONE_FAULT | BOOL | — |
| ALM_NO_CAPACITY | BOOL | — |
| ALM_CFG_ERR | BOOL | — |
IEC 61499 event interface
EI INIT, REQ·EO INITO, CNF
Supervised control write
RTU_CTRL 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
- 12
- Simulated scans
- 507
- 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 RTU_CTRL — 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.