Smart Irrigation Water Blending & Salinity Control Station RC-IWB-600

Overview

The RC-IWB-600 is a grid-powered irrigation water blending and salinity control station from REDCOAST.LTD for landscaped campuses, public parks, sports facilities, and commercial nurseries with two available water sources. It combines a metered hydraulic skid, local control cabinet, Web management platform, and mobile app to regulate how much lower-conductivity and higher-conductivity water enters the irrigation supply. Operators gain repeatable blending recipes, source-volume records, and automatic shutdown when the agreed operating conditions cannot be maintained. This configured-to-order product addresses water-source management upstream of irrigation scheduling and fertilizer injection; the specifications below define a proposed engineering configuration and acceptance targets, with final ratings fixed in the project datasheet.

Key Features

• Three-point conductivity measurement: Monitor both incoming sources and the mixed outlet using temperature-compensated EC measurements, so changes in source quality are visible before operators adjust a recipe.
• Measured source allocation: Three electromagnetic flowmeters record each inlet and the common outlet, providing source totals and a flow-balance diagnostic with configurable delay and tolerance.
• Closed-loop blending: Independent modulating valves combine a calculated starting ratio with outlet EC feedback, reducing dependence on manually adjusted valves.
• Local operating continuity: Approved recipes, permissive checks, and alarms execute locally when the Internet connection is unavailable; remote access enhances supervision without carrying the control loop.
• Defined fault response: Low source level, insufficient pressure, invalid conductivity, valve-position faults, and sustained outlet EC excursions withdraw the irrigation permissive and initiate a controlled stop.
• Practical plant integration: Pump-run permissions, treatment-ready inputs, an irrigation-demand contact, and Modbus interfaces connect the skid to existing pumping, treatment, and landscape-control equipment.
• Traceable water management: The platform records requested and measured EC, source fractions, delivered volume, alarm acknowledgments, and operator changes for maintenance and resource reporting.
• Project-specific electronics: REDCOAST.LTD develops the conductivity acquisition, isolated field-interface, valve-control, and supervisory controller PCBs to match the selected instruments and operating sequence.

Technical Architecture

The base skid has two DN50 pressurized inlets and one DN65 outlet. Each inlet includes service isolation, a check valve, an electromagnetic flowmeter, an EC/temperature probe, a pressure transmitter, and a modulating valve with spring-return closure. The streams join upstream of a static mixer; a third EC probe and flowmeter measure the blended water before delivery. Sample and drain points support calibration and winterization. Both supplies enter as non-potable process water: any drinking-water top-up must first pass through a separately engineered break tank and suitable air gap. Feed pumps, upstream treatment, and the downstream irrigation distribution system are separate equipment with defined control interfaces.

The controller initially estimates the higher-EC source fraction as (EC_target - EC_A) / (EC_B - EC_A), using measurements referenced to 25°C and only when source B has a sufficiently higher EC than source A. This is a starting approximation, because conductivity is affected by ionic composition and is not an exact mass-concentration measurement. Flow feedback establishes the requested ratio, while the outlet EC loop trims it after allowing for pipe transport, mixing, sensor response, and actuator travel. A setpoint outside the achievable source range generates an unavailable-recipe alarm; nearly equal source readings disable the ratio calculation. Commercial process-water blending also uses flow and conductivity feedback, as illustrated by Bürkert's blending-system reference.

The REDCOAST.LTD acquisition PCB provides alternating excitation and temperature inputs for compatible conductivity cells, with isolated interfaces separating field signals from the controller. A dedicated I/O board reads pressure, flow, tank-level contacts, and actuator feedback; the supervisory board manages recipes, timestamps, local storage, and authenticated communication. Startup water must pass through a commissioned return or diversion route until outlet quality is qualified, or enter a designated non-potable buffer tank while irrigation delivery remains disabled. If no suitable startup route exists, automatic direct-to-network startup is not enabled. The Web platform and app display trends and maintenance tasks, while local logic retains authority over permissives and shutdown.

Connectivity & Power

The station operates from AC 100–240 V, 50/60 Hz, at an existing pump house, utility compound, or landscaped-site service point. An isolated 24 V DC supply powers instruments, controls, and actuators. The base electrical budget is 40–90 W during normal operation and 180 W maximum, excluding source pumps, external diversion equipment, pipe heating, and building ventilation. The published configuration contains no photovoltaic array or battery.

Ethernet is the standard uplink for managed sites; optional 4G LTE provides access where a network cable is impractical, with the modem variant selected for local bands and operator approval. Two isolated RS-485 ports and Modbus TCP support field and supervisory integration. MQTT over TLS and HTTPS carry telemetry and configuration through an approved network path. Remote commands require authorized accounts and remain subject to local interlocks; buffered records upload after connectivity returns. Mains failure removes pump and irrigation permissions, and mechanical spring-return actuators close the source valves without cloud access.

Protection & Reliability

The control cabinet has an IP65 design target with sealed cable entries, segregated mains wiring, protective earthing, and surge protection coordinated with the site electrical system. The base wet skid is specified for ambient temperatures of +5 to +45°C and water temperatures of +5 to +40°C. Operation outside that envelope requires a separately sized shelter, ventilation, insulation, or trace-heating package; an electronics component temperature rating does not establish the temperature rating of the assembled skid.

The steel frame and cabinet use hot-dip galvanizing beneath a smooth matte powder-coated finish. Coastal exposure calls for a specified coating system, compatible fasteners, and a maintenance plan; no salt-spray duration or corrosion lifetime is claimed without the selected assembly's test evidence. PVC-U manifolds, EPDM seals, and compatible probe materials are checked against actual water chemistry, including cleaning agents. Outdoor installations require sun protection for exposed polymer pipework and anchors designed for the site's wind and structural conditions.

Valve closure timing must be coordinated with pump stopping and transient-pressure analysis. Fault detection cannot remove water already between the outlet sensor and the irrigation emitters, so the selected buffer or diversion arrangement determines containment performance. Replaceable probes, accessible strainers, manual sampling points, and pluggable controller modules support maintenance. Warranty duration, spare-parts provision, and service response are defined in the supply agreement rather than inferred from component ratings.

Application Scenarios

• Campus landscape water-source management: Install the station in a grid-connected irrigation service compound receiving treated reclaimed water and a lower-EC supply from an isolated storage tank. Facilities teams can apply approved blending recipes and review how much of each source supplied individual irrigation periods.
• Public parks with borehole and stored rainwater: Place the skid between the source pumps and the irrigation header. Measured source EC helps the controller adjust proportions as borehole conductivity changes or stored rainwater becomes scarce.
• Sports turf and golf practice facilities: Use centrally approved water-quality recipes for turf areas with different agronomic requirements. Operators can review delivered EC alongside soil testing and drainage observations rather than treating one water-quality reading as proof of turf health.
• Commercial nurseries and landscape plant production: Stabilize incoming irrigation-water EC before a separate fertilizer dosing unit. A predictable starting-water condition makes nutrient-recipe management easier, while the nutrient controller retains responsibility for final fertilizer EC and pH.
• Municipal landscape maintenance depots: Feed an existing non-potable irrigation-water buffer tank from two available sources. Tank-level permissions and source totals help operators coordinate filling with irrigation demand and investigate unexpected source consumption.

Case-style Examples

The following are illustrative engineering scenarios, not completed customer installations or measured savings claims.

Campus reclaimed-water blending. A campus has treated reclaimed water at 2.2 mS/cm and an isolated lower-EC supply at 0.4 mS/cm, with a proposed irrigation target of 1.0 mS/cm at 12 m³/h. The starting estimate is 33.3% reclaimed water, approximately 4 m³/h, mixed with 8 m³/h of the lower-EC source. Outlet feedback adjusts that estimate after mixing; the expected operational benefit is a recorded, repeatable source allocation within an agronomist-approved operating window, subject to separate reclaimed-water quality approval.

Nursery borehole-water stabilization. A nursery's borehole EC varies during the season while stored rainwater is available intermittently. The station measures both sources, verifies minimum tank levels, and supplies a buffer tank ahead of the existing fertigation unit. When rainwater is depleted, an unavailable-recipe condition stops blending or invokes an explicitly approved alternative recipe, preventing an unnoticed change in the nutrient system's incoming water.

Sports-ground retrofit with an existing controller. A grounds team retains its irrigation scheduler and pump controls but adds the RC-IWB-600 upstream of the irrigation buffer tank. A demand contact requests blending, and a treatment-ready contact permits the reclaimed-water source. The intended result is clearer separation of scheduling, source-quality control, and pump operation, with source-volume reports available to the maintenance team.

Customization & Selection Guide

Start with simultaneous source-water analyses, minimum and maximum demand, available inlet pressures, outlet pressure requirements, and the hydraulic drawing. EC is useful for salinity control, but sodium adsorption ratio, chloride, boron, alkalinity, microbiological quality, soil drainage, and plant sensitivity require separate assessment. Guidance on irrigation suitability treats these as distinct issues; blending does not remove salt or establish that reused water is hygienically suitable. Oregon State University irrigation-water guidance and FAO water-quality evaluation guidance explain these assessment boundaries.

Select the base skid for a total flow of 5–20 m³/h, with at least 1 m³/h through each active inlet during continuous two-source blending. Consequently, the continuous blend range is approximately 20–80% at 5 m³/h and 5–95% at 20 m³/h; 0% and 100% are separate single-source operating modes. Lower minor-source flows need smaller meter and valve trims or a separately engineered batch arrangement. Neither a DN connection size nor the 2–6 bar service-pressure envelope guarantees the required flow: valve authority, mixer loss, meter installation conditions, and downstream pressure must be checked together.

For tighter outlet supervision, select an additional independent EC transmitter and an external diversion valve with position feedback. Select a pressure-managed feed package when existing source pressures cannot provide stable blending, and a protected wet enclosure where freezing or excessive solar heating is credible. Existing landscape controllers can connect through simple demand/permissive contacts; sites requiring central reporting can select a private server or managed platform deployment. Each quoted option identifies its instruments, wiring, firmware behavior, and acceptance tests.

Deployment & After-sales

Installation begins with a P&ID, source-water review, electrical load schedule, communications plan, and agreed fault-response matrix. The skid mounts on a level, drained concrete pad with service access around meters and valves. The installer provides approved source isolation, upstream filtration nominally rated at 130 µm or finer where required by the selected components, appropriate pipe supports, and a safe return or diversion destination. Drinking-water connections require a risk-appropriate physical separation arrangement; inlet check valves are process components and do not constitute the complete potable-water protection scheme.

Factory acceptance should verify pressure integrity at the approved test pressure, meter scaling, probe calibration, I/O mapping, actuator feedback, and shutdown behavior. Site acceptance then checks actual pressure losses, representative blending points, startup qualification, communication loss, source depletion, and restart after mains failure. The outlet-regulation acceptance target applies after stable flow and mixing have been established, with a planned stabilization window of 120–300 seconds to be confirmed during commissioning.

Delivery scheduling follows approval of the hydraulic design, PCB scope, selected instruments, and test plan. A new PCB layout or additional independent protection channel requires prototype and verification time before production release. Handover includes wiring diagrams, configuration backups, calibration instructions, spare-parts lists, and operator training. Initial maintenance should include weekly visual and strainer checks and monthly comparison of EC readings with a calibrated reference, with intervals adjusted using site fouling and drift records.

Standards & Compliance

The project compliance plan addresses cabinet ingress protection under IEC 60529, electrical measurement/control safety under IEC 61010-1, and EMC under IEC 61326-1:2020. These identify assessment scopes, not certificates already issued for the RC-IWB-600. Final acceptance requires evidence for the supplied assembly and its intended installation. IEC ingress-protection publication record, IEC 61010-1 scope, and IEC 61326-1:2020 scope provide the relevant reference framework.

Where treated wastewater is used, ISO 16075-2:2020 provides guidance on project development, water quality, crops, and exposure barriers; it is not a product certification or an EC-only water-release rule. The ISO catalogue records confirmation of this edition in 2026. ISO 16075-2:2020. Potable-water separation is designed to the locally applicable requirements; EN 1717 and its applicable national adoption may form part of that assessment. BSI's current backflow-protection standard record.

The destination-market conformity plan also determines applicable electrical, radio, restricted-substance, pressure-equipment, and installation requirements. CE marking, RoHS documentation, radio approvals, or other requested evidence must match the delivered configuration. No universal certification, hazardous-area rating, drinking-water approval, or regulatory water-quality compliance is implied by this concept specification.

Why REDCOAST.LTD

REDCOAST.LTD delivers the hydraulic controls, embedded firmware, Web platform, and mobile app as one coordinated irrigation-water management solution. In-house PCB and board-level hardware design allows the team to change sensor excitation, input protection, isolation, valve interfaces, and communications around the customer's actual equipment. That flexibility is useful when retrofitting a pump house whose wiring, instruments, or operating sequence do not fit an off-the-shelf controller.

Project delivery connects those hardware decisions to readable operating screens, documented interfaces, testable fault behavior, and service instructions. Buyers can request a defined skid configuration or a site-specific arrangement while retaining an agreed specification and acceptance process.

Contact REDCOAST.LTD with your source-water analyses, required flow, inlet and outlet pressures, and site layout to request a customized RC-IWB-600 blending-station proposal.