VAV_BOX_CTRL
Pressure-independent VAV terminal box with dual-maximum reheat and a starved-flow alarm.
When to use it
Use VAV_BOX_CTRL when a VAV terminal unit serves one zone from a variable-pressure trunk, with a measured airflow (a flow cross or velocity sensor) and optionally a reheat coil.
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 | — |
| FLOW | REAL | l/s |
| FLOW_OK | BOOL | — |
| FLOW_MIN | REAL | l/s |
| FLOW_MAX | REAL | l/s |
| FLOW_HTG_MAX | REAL | l/s |
| FLOW_MIN_UNOCC | REAL | l/s |
| DB_K | REAL | K |
| KP_Z | REAL | %/K |
| TI_Z | TIME | — |
| KP_F | REAL | %/(l/s) |
| TI_F | TIME | — |
| FLOW_TMO | TIME | — |
| ACK | BOOL | — |
Outputs
| Port | Type | Unit |
|---|---|---|
| DMPR_POS | REAL | % |
| REHEAT_VLV | REAL | % |
| FLOW_SP | REAL | l/s |
| COOLING | BOOL | — |
| HEATING | BOOL | — |
| VALID | BOOL | — |
| ALM_ZONE_FAULT | BOOL | — |
| ALM_FLOW_FAULT | BOOL | — |
| ALM_FLOW_LOW | BOOL | — |
| ALM_CFG_ERR | BOOL | — |
IEC 61499 event interface
EI INIT, REQ·EO INITO, CNF
Validation evidence
- Tests
- 9
- Simulated scans
- 120
- 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 VAV_BOX_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.