Product details
Continuous Inline DO Measurement, Engineered for Australian Process Conditions
The InstroDirect IDO-F40i Industrial Fluorescence Dissolved Oxygen Sensor uses fluorescence-quenching optical technology to measure dissolved oxygen concentration in water without a consumable membrane or electrolyte solution. Compared to legacy galvanic and polarographic probes, the optical method delivers longer service intervals, zero oxygen consumption at the sensor face, and no flow-rate dependency — meaning you can mount it in a still tank or a turbulent aeration basin and get the same reading.
Built for panel builders, system integrators, wastewater operators, and aquaculture farmers who need a sensor that drops into a 316 stainless housing, talks Modbus to any PLC, and runs for 12 months between calibrations.
Technical Specifications
| Parameter | Specification |
|---|---|
| Measurement method | Fluorescence quenching (optical) |
| DO measurement range | 0–20 mg/L (equivalent to 0–200 % saturation) |
| Accuracy | ±0.3 mg/L |
| Temperature measurement | 0–60 °C, Pt1000 integrated |
| Compensation | Temperature, salinity, atmospheric pressure (all in-sensor) |
| Output signal | RS485 Modbus RTU, up to 115200 bps |
| Power supply | 12–24 VDC |
| Power consumption | <0.5 W |
| Housing material | Titanium alloy & 316 stainless steel |
| Ingress protection | IP68 (fully submersible) |
| Dimensions | 205 mm × Ø40 mm |
| Standard cable | 5 m, 4-core shielded (10 m / 20 m / 50 m on request) |
| Warranty | 12 months, Australian-backed |
Typical Australian Applications
- Wastewater treatment plants — DO control loop for aeration blowers, SCADA integration into existing B&R / AB / Schneider systems
- Aquaculture — prawn and barramundi farms, RAS (recirculating aquaculture), trout raceways, pond DO telemetry
- Surface water monitoring — rivers, dams, stormwater discharge compliance, council environmental monitoring
- Food & beverage — brewery fermentation, kombucha, soft-drink bottling line inline DO, dairy wash-water monitoring
- Pulp & paper, mining — process water DO tracking
- Environmental compliance — EPA reporting, NATA-traceable data logging with proper calibration chain
Why Integrators Choose the IDO-F40i
- Native Modbus RTU — drops directly into Allen-Bradley CompactLogix, Siemens S7-1200/1500, or Schneider M221/M580 panels through any Modbus master port or gateway
- 12–24 VDC input — runs off your existing panel supply, no separate 240 VAC drop needed
- No membrane, no electrolyte — maintenance is a quick optical cap clean, not a messy membrane service
- 316 SS & titanium body — rated for permanent installation in chloride-rich wastewater and saline aquaculture
- In-sensor compensation — salinity, atmospheric pressure, and temperature all corrected before the register is read; no lookup tables in your ladder logic
- Local Australian support — phone a field engineer in Brisbane, not a ticket queue in another timezone
Wiring (Standard 4-Core Shielded)
- Brown → +12/24 VDC
- Black → 0 V common
- Yellow → RS485 A
- Blue → RS485 B
- Shield → terminate at panel earth bar only (single-point earth)
Modbus register map PDF ships with every order. Default slave ID 0x01, configurable in field. Key registers: DO (mg/L, float32), Temperature (°C, float32), Saturation (%, float32), Sensor status word.
Australian Technical Support, Calibration & Consumables
Every InstroDirect DO sensor is backed by:
- Phone and email technical support from AU-based field engineers with 20+ years automation experience
- On-site calibration service available across QLD, NSW, VIC — two-point calibration (zero DO + air saturation) with certificate
- Replacement optical caps stocked locally — typical 12–24 month service interval
- Zero-DO and air-saturation calibration references for two-point field calibration
- Next-day dispatch ex Brisbane for stock items
Need reagents for the rest of your water-quality programme — pH, chlorine, ammonia, nitrate? InstroDirect stocks the full reagent range across our water analysis product line.
Frequently Asked Questions
Does this sensor need a membrane replaced regularly?
No traditional membrane. The sensor uses fluorescence-quenching optical technology — there is no ion-exchange membrane, no electrolyte fill, and no oxygen consumption at the sensor face. The fluorescence cap itself is a consumable, but typical service life is 12–24 months depending on biofouling, and swap-out takes under a minute.
What is the difference between mg/L and % saturation?
mg/L is concentration — the actual mass of oxygen per litre of water. % saturation is the oxygen concentration relative to what the water could theoretically hold at the current temperature, salinity, and atmospheric pressure. Wastewater aeration control typically uses mg/L. Environmental and fisheries monitoring typically uses % saturation.
Can I use this with Allen-Bradley PLCs?
Yes. RS485 Modbus RTU integrates into CompactLogix / ControlLogix via any Modbus master module (1756-MVI, Prosoft MVI56E-MNET) or via a Modbus TCP gateway. Register map and sample ladder logic are supplied on request.
Do you offer on-site calibration in Australia?
Yes. InstroDirect provides on-site two-point DO calibration across QLD, NSW, and VIC, with an accredited calibration certificate. Remote support via video call is available for WA, SA, TAS, and NT sites.
What consumables will I need?
Zero-DO and air-saturation calibration references for a two-point field calibration every 6–12 months, plus a replacement fluorescence cap every 12–24 months. Both are stocked in Australia.
Request a Trade Quote
Panel builders, integrators, council water departments, and aquaculture operators get volume trade pricing. Submit a quote request and we’ll respond within one business day with stock, pricing, and lead time.
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