VFD_PUMP_PID
Pump VFD PI(D) loop in flow, pressure or wet-well level mode, with correct action sense, anti-windup, minimum-speed clamp, turndown stop and an affinity-law power estimate.
When to use it
Use VFD_PUMP_PID when a variable-speed pump has to hold a flow, a discharge pressure or a wet-well level, and the drive must never be commanded below the speed at which the pump loses cooling, loses prime, or lets solids settle in the rising main.
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 | — |
| MODE | USINT | — |
| SP | REAL | EU (m3/h, kPa or %) |
| PV | REAL | EU (m3/h, kPa or %) |
| PV_OK | BOOL | — |
| KP | REAL | %/EU |
| TI_S | REAL | s |
| TD_S | REAL | s |
| SPD_MIN | REAL | % |
| SPD_MAX | REAL | % |
| FAIL_SPD_PCT | REAL | % |
| TURNDOWN_TMO | TIME | — |
| STOP_ON_TURNDOWN | BOOL | — |
| MIN_OFF | TIME | — |
| RESTART_DB_PCT | REAL | % |
| MAN | BOOL | — |
| MAN_SPD_PCT | REAL | % |
| KW_RATED | REAL | kW |
Outputs
| Port | Type | Unit |
|---|---|---|
| SPEED_PCT | REAL | % |
| RUN_CMD | BOOL | — |
| KW | REAL | kW |
| KW_VALID | BOOL | — |
| ERR_EU | REAL | EU (m3/h, kPa or %) |
| AT_MIN_SPD | BOOL | — |
| AT_MAX_SPD | BOOL | — |
| TURNDOWN | BOOL | — |
| RESTART_INH | BOOL | — |
| ALM_PV_FAULT | BOOL | — |
| ALM_CFG_ERR | BOOL | — |
IEC 61499 event interface
EI INIT, REQ·EO INITO, CNF
Supervised control write
VFD_PUMP_PID 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
- 11
- Simulated scans
- 223
- 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 VFD_PUMP_PID — 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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