DCW_ORP_CTRL
Oxidant residual control on either ORP or free chlorine, with separate under- and over-residual alarms and a maximum-continuous-feed latch.
When to use it
Use DCW_ORP_CTRL when a continuous oxidising biocide feed (hypochlorite, bromine, chlorine dioxide) is trimmed against an ORP or free-chlorine measurement on the circulating water.
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 | — |
| PV | REAL | mV | mg/L |
| PV_OK | BOOL | — |
| MODE | INT | — |
| SP_ORP_MV | REAL | mV |
| LO_ORP_MV | REAL | mV |
| HI_ORP_MV | REAL | mV |
| KP_ORP | REAL | %/mV |
| SP_FC_MGL | REAL | mg/L |
| LO_FC_MGL | REAL | mg/L |
| HI_FC_MGL | REAL | mg/L |
| KP_FC | REAL | %/(mg/L) |
| MIN_PCT | REAL | % |
| MAX_PCT | REAL | % |
| RES_TMO | TIME | — |
| HOLD_TMO | TIME | — |
| MAX_FEED_TMO | TIME | — |
| FROZEN_TMO | TIME | — |
| DOSE_INHIBIT | BOOL | — |
| ACK | BOOL | — |
Outputs
| Port | Type | Unit |
|---|---|---|
| OUT_PCT | REAL | % |
| FEEDING | BOOL | — |
| RESID_OK | BOOL | — |
| SP_ACTIVE | REAL | mV | mg/L |
| HELD | BOOL | — |
| ALM_LOW_RES | BOOL | — |
| ALM_HIGH_RES | BOOL | — |
| ALM_MAX_FEED | BOOL | — |
| ALM_PV_FAULT | BOOL | — |
| ALM_CFG_ERR | BOOL | — |
IEC 61499 event interface
EI INIT, REQ·EO INITO, CNF
Supervised control write
DCW_ORP_CTRL 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
- 12
- Simulated scans
- 374
- 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 DCW_ORP_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.