DCW_BACKWASH_SEQ
Multi-step filter backwash sequencer — isolate, drain, optional air scour, backwash, settle, rinse, return — with per-step timeout supervision.
When to use it
Use DCW_BACKWASH_SEQ when a pressure sand, multimedia or activated-carbon filter has to be backwashed by a valve sequence rather than by a mechanical multiport head, and the wash must be supervised step by step so a failed valve or a failed wash pump 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 | — |
| ISOLATED_FB | BOOL | — |
| DRAIN_LOW_FB | BOOL | — |
| AIR_OK | BOOL | — |
| RINSE_OK | BOOL | — |
| BW_READY_FB | BOOL | — |
| BW_FLOW | REAL | m3/h |
| BW_FLOW_MIN | REAL | m3/h |
| ISOLATE_T | TIME | — |
| DRAIN_T | TIME | — |
| AIR_T | TIME | — |
| BW_T | TIME | — |
| SETTLE_T | TIME | — |
| RINSE_T | TIME | — |
| RETURN_T | TIME | — |
| BW_PUMP_DLY | TIME | — |
| STEP_TMO_MARGIN | TIME | — |
Outputs
| Port | Type | Unit |
|---|---|---|
| STATE | DINT | — |
| BUSY | BOOL | — |
| FILTER_UNAVAIL | BOOL | — |
| WASH_DONE | BOOL | — |
| ABORTED | BOOL | — |
| CMD_INLET | BOOL | — |
| CMD_OUTLET | BOOL | — |
| CMD_DRAIN | BOOL | — |
| CMD_BW_INLET | BOOL | — |
| CMD_BW_PUMP | BOOL | — |
| CMD_AIR | 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 | DINT | — |
| ALM_NO_BW_FLOW | BOOL | — |
| ALM_CFG_ERR | BOOL | — |
Supervised control write
DCW_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
- 16
- Simulated scans
- 609
- 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 DCW_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.
Every block in the catalogue is free to download, in every format it ships, with no purchase and no card. Browsing needs no account at all; downloading needs a signed-in one, so the block lands in your library and re-downloads whenever you need it.
Source is never published on this page. The implementation is released to a signed-in Ri Tech account — free of charge, but never anonymously.