BACKWASH_SEQ
Gravity-filter backwash sequencer — drain, air scour, combined air-and-water, rinse, return — with per-step supervision and a proven-flow wash dwell.
When to use it
Use BACKWASH_SEQ when a rapid gravity or dual-media filter is washed by an air-scour-then-air-and-water sequence driven from valve commands, and each step has to be supervised so a valve that does not stroke or a washwater pump that does not start is reported instead of being washed over.
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 | — |
| START | BOOL | — |
| ABORT | BOOL | — |
| ACK | BOOL | — |
| AIR_FITTED | BOOL | — |
| DRAIN_LOW_FB | BOOL | — |
| AIR_OK | BOOL | — |
| RINSE_OK | BOOL | — |
| OUTLET_FB | BOOL | — |
| BW_FLOW | REAL | m3/h |
| BW_FLOW_MIN | REAL | m3/h |
| AIR_WATER_AIR_EN | BOOL | — |
| BW_FLOW_MAX_AIR | REAL | m3/h |
| DRAIN_T | TIME | — |
| AIR_T | TIME | — |
| AIR_WATER_T | TIME | — |
| RINSE_T | TIME | — |
| RETURN_T | TIME | — |
| STEP_TMO_MARGIN | TIME | — |
Outputs
| Port | Type | Unit |
|---|---|---|
| STEP | USINT | — |
| BUSY | BOOL | — |
| FILTER_UNAVAIL | BOOL | — |
| DONE | BOOL | — |
| ABORTED | BOOL | — |
| CMD_INLET | BOOL | — |
| CMD_OUTLET | BOOL | — |
| CMD_DRAIN | BOOL | — |
| CMD_AIR | BOOL | — |
| CMD_BW_PUMP | BOOL | — |
| CMD_WASTE | BOOL | — |
| STEP_PCT | REAL | % |
| STEP_ELAPSED_S | REAL | s |
| WASH_COUNT | DINT | — |
| LAST_WASH_S | REAL | s |
| LAST_WASH_M3 | REAL | m3 |
| ALM_STEP_FAULT | BOOL | — |
| FAULT_STEP | USINT | — |
| ALM_NO_BW_FLOW | BOOL | — |
| ALM_COMBINED_RATE_HIGH | BOOL | — |
| ALM_CFG_ERR | BOOL | — |
Supervised control write
BACKWASH_SEQ 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
- 327
- 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
Download BACKWASH_SEQ — 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 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.