CW_PUMP_VFD_CTRL
Chilled-water pump VFD speed control on loop differential pressure, with a minimum-speed floor and an affinity-law power estimate.
When to use it
Use CW_PUMP_VFD_CTRL when a variable-speed chilled-water pump holds a differential pressure across the distribution loop, the drive must not be taken below the speed at which the pump makes head or the chillers lose minimum flow, and the loop must never be allowed to stop because a transmitter died.
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 | — |
| DP_SP | REAL | kPa |
| DP_PV | REAL | kPa |
| DP_OK | BOOL | — |
| SPD_MIN | REAL | % |
| SPD_MAX | REAL | % |
| KP | REAL | %/kPa |
| TI | REAL | s |
| RATED_KW | REAL | kW |
| FAIL_SPD_PCT | REAL | % |
| LOW_DP_DEV | REAL | kPa |
| LOW_DP_TMO | TIME | — |
| ACK | BOOL | — |
Outputs
| Port | Type | Unit |
|---|---|---|
| SPEED_PCT | REAL | % |
| KW | REAL | kW |
| AT_MAX | BOOL | — |
| VALID | BOOL | — |
| ALM_DP_FAULT | BOOL | — |
| ALM_DP_LOW | BOOL | — |
| ALM_CFG_ERR | BOOL | — |
IEC 61499 event interface
EI INIT, REQ·EO INITO, CNF
Validation evidence
- Tests
- 6
- Simulated scans
- 3175
- 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 CW_PUMP_VFD_CTRL — free
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