DODO AQUA EC
Online Conductivity & TDS Sensor
Conductivity · TDS · Temperature
- Six ranges, 0-400 mS/cm
- EC + TDS + temperature
- ±1 % of reading
- RS-485 Modbus-RTU
- IP68, 3/4" NPT immersion
- 5 m cable, GX12 fitted
Works with DODO LOGGER, the DODOTiK Platform and the DODOLINK app — see how.
Overview
DODO AQUA EC (DOT-ECS-200) measures electrical conductivity, total dissolved solids and temperature in one submersible probe, over RS-485 Modbus-RTU.
Conductivity is the workhorse measurement of water treatment: it is how you tell that an RO membrane is passing salt, that a boiler needs blowing down, that a rinse tank has stopped rinsing, or that a borehole has started drawing saline water. TDS is the same measurement expressed the way the people who read the report prefer it, through a coefficient that is user-settable on this device (default 0.64) so the conversion matches your water rather than a generic one.
The product spans six measuring ranges across three cell constants, from ultrapure water at 0-20 µS/cm up to brine at 0-400 mS/cm. The range and cell constant are factory-set and specified at order - see Ordering information.
Key features
- Three measurands, one probe - conductivity, TDS and temperature
- Six ranges - 0-20 µS/cm through 0-400 mS/cm, across three cell constants
- User-settable TDS coefficient - default 0.64, changed over the bus to suit the water
- Compensated - automatic temperature compensation via Pt1000
- Selectable baud - 9600 or 19200 over the bus
- Low power - < 0.1 W at 12 V, the lowest draw in the DODO AQUA family
- Submersible - IP68, 3/4" NPT thread, < 0.6 MPa working pressure
Measured parameters
| Parameter | Unit | Range | Accuracy | Resolution |
|---|---|---|---|---|
| Electrical conductivity | µS/cm or mS/cm | Six ranges - see Ordering information | ±1 % of reading | Range-dependent - see Ordering information |
| Total dissolved solids (TDS) | mg/L or g/L | Range-dependent | ±1 % of reading | Range-dependent |
| Temperature | °C | 0-65 °C | ±0.3 °C | 0.1 °C |
Technical specifications
Measurement
| Parameter | Value |
|---|---|
| Measured parameters | Conductivity, TDS and temperature |
| Measuring range | Six ranges, 0-20 µS/cm … 0-400 mS/cm - see Ordering information |
| Cell constants | K = 0.01, 0.1, 1.0 |
| Accuracy | ±1 % of reading; temperature ±0.3 °C |
| TDS coefficient | 0.64 default, user-settable over the bus |
| Temperature compensation | Automatic (Pt1000) |
| Calibration | Two-point - zero in air, slope in a standard solution |
Electrical
| Parameter | Value |
|---|---|
| Supply voltage | DC 12-24 V ±10 % |
| Power consumption | < 0.1 W @ 12 V |
| Output | RS-485, Modbus-RTU |
| Baud rate | 9600 (default) or 19200, selectable over the bus |
| Frame format | 8 data bits, 1 stop bit, no parity (8N1) |
| Default slave address | 6 |
| Addressing | Field-changeable over the bus, range 1-127 |
| Cable | 5 m, Φ6 mm shielded, corrosion-resistant jacket, GX12 4-pin female fitted; other lengths on request |
Mechanical & environmental
| Parameter | Value |
|---|---|
| Body diameter | Φ30 mm |
| Overall length | 163 mm (K = 0.01) · 192 mm (K = 0.1) · 185 mm (K = 1.0) |
| Wetted material | ABS and ABS/PC alloy |
| Mounting | Immersion, 3/4" NPT thread - tank, pipe or submerged |
| Working temperature | 0 … +65 °C |
| Working pressure | < 0.6 MPa |
| Ingress protection | IP68 |
Plug DA-EC into DODO LOGGER and it is already on your phone
No firmware reflash, no driver to write, no backend deployment. The logger self-describes its schema to the platform, so a new sensor appears in the dashboard and in the app on its own.
1 · Plug in
The fitted GX12 4-pin connector screws onto the logger's Modbus RS-485 socket. No stripping, no terminal block, no tools. Up to four sensors per logger.
2 · Select it
DA-EC is in the logger's no-code sensor library. Pick it in the web interface, assign a slot, and it starts logging.
3 · Logged locally
Every reading to microSD, always on, offline included. CSV download straight off the card.
4 · Live in the cloud
MQTT/TLS to the DODOTiK Platform — live dashboards, full history, alert thresholds, device management.
5 · On a phone
The same readings and alerts in DODOLINK for iOS and Android, for whoever is out in the field rather than at a desk.
Nothing here is lock-in. DA-EC is a standard Modbus-RTU device on a standard RS-485 bus. The DODO LOGGER, the platform and the app are the fastest route from probe to dashboard, not the only one — the full register map is published below and in the datasheet, and the sensor can be ordered with bare leads for a PLC, DCS, SCADA or paperless recorder.
Dimensions
| Dimension | Value |
|---|---|
| Overall length, K = 0.01 | 163 mm |
| Overall length, K = 0.1 | 192 mm |
| Overall length, K = 1.0 | 185 mm |
| Body diameter | Φ30 mm |
| Electrode diameter, K = 0.01 / 0.1 | Φ19 mm |
| Electrode diameter, K = 1.0 | Φ23 mm |
| Process thread | 3/4" NPT, both ends |
| Cable length | 5 m (standard) |
Wiring — GX12 4-pin connector
The cable is terminated in a GX12 4-pin female aviation connector, fitted as standard. It screws directly onto the DODO LOGGER Modbus RS-485 socket. For a third-party logger or a terminal block, order the bare-lead variant rather than cutting the connector off at the sensor's gland — the gland is part of the IP68 seal.
| Pin | Signal | Function |
|---|---|---|
| 1 | VCC | Power + (DC 12-24 V) |
| 2 | GND | Ground |
| 3 | A (D+) | RS-485 A |
| 4 | B (D−) | RS-485 B |
Modbus RTU register map
RS-485 Modbus-RTU, 9600 baud, 8 data bits, 1 stop bit, no parity. Default slave address 6. Published in full so the sensor can be read by any Modbus master — PLC, DCS, SCADA or a paperless recorder.
| Register | Value | Access | Notes |
|---|---|---|---|
| 0x0000 | Measured value + temperature | Read | 4 registers: conductivity, decimals, temperature, temperature decimals |
| 0x1000 | Zero calibration | Write | In air; write 0 |
| 0x1004 | Slope calibration | Write | In a standard solution; write the standard's actual value (see 9.4) |
| 0x1010 | Temperature calibration | Read / Write | Write actual temperature × 10; read the stored offset × 10 |
| 0x1030 | TDS coefficient | Read / Write | Default 0.64; change to suit the water |
| 0x2002 | Device address | Read / Write | Default 6, range 1-127 |
| 0x2003 | Baud rate | Read / Write | 0 = 9600 (default) · 1 = 19200 |
| 0x2020 | Factory reset | Write | Write 0 - restores factory calibration. Recalibrate after a reset |
Calibration
Calibration is performed over the bus — there is no handheld meter to carry and no transmitter to adjust.
Two points: zero in air, slope in a standard solution.
Zero, in air. Rinse the probe in distilled water and blot it dry with filter paper. Leave it powered and standing in air for about 3 minutes - a damp cell will not zero. When the reading has settled, write the zero command.
Slope, in a standard solution. Use a standard between 20 % of full scale and full scale for the range the sensor was built for. Stand the probe vertically with at least 2 cm of clearance from the container floor and walls. Write the slope command with the standard's actual value.
The scaling of the value written to the slope register depends on the range the unit was built for - see the register map.
Calibration commands
| Operation | Request | Response |
|---|---|---|
| Zero, in air | 06 06 10 00 00 00 8C BD | 06 06 10 00 00 00 8C BD |
| Slope, 5000 µS/cm standard | 06 06 10 04 13 88 C0 2A | 06 06 10 04 13 88 C0 2A |
| Slope, 50 mS/cm standard | 06 06 10 04 01 F4 CD 6B | 06 06 10 04 01 F4 CD 6B |
Applications
Reverse osmosis - permeate quality and membrane-breakthrough alarms
Boiler and cooling water - blowdown control on cycles of concentration
Drinking-water distribution - TDS compliance and source-blending control
Rinse tanks - plating and food-plant rinse-water quality
Hydroponics and fertigation - nutrient-solution strength
Groundwater and borehole monitoring - saline-intrusion early warning
Before you specify it
Limits worth knowing before the order goes in, rather than after the sensor is in the ground.
- Range and cell constant are factory-set; neither can be changed in the field.
- The slope-calibration scaling depends on the range the unit was built for.
Ordering information
| Order code | Description |
|---|---|
| DA-EC-K001-20U | K = 0.01 · EC 0-20.00 µS/cm · TDS 0-10 mg/L · resolution 0.01 µS/cm |
| DA-EC-K001-200U | K = 0.01 · EC 0-200.0 µS/cm · TDS 0-100 mg/L · resolution 0.1 µS/cm |
| DA-EC-K01-5K | K = 0.1 · EC 0-5000 µS/cm · TDS 0-3500 mg/L · resolution 1 µS/cm |
| DA-EC-K1-20K | K = 1.0 · EC 0-20 000 µS/cm · TDS 0-10 000 mg/L · resolution 1 µS/cm |
| DA-EC-K1-200M | K = 1.0 · EC 0-200.0 mS/cm · TDS 0-100 g/L · resolution 0.1 mS/cm |
| DA-EC-K1-400M | K = 1.0 · EC 0-400 mS/cm · TDS 0-200 g/L · resolution 0.1 mS/cm |
| …-L10 / -L20 | Any of the above with a 10 m or 20 m cable |
| …-BL | Any of the above with bare leads instead of the GX12 connector |
What's in the box
- DODO AQUA EC sensor with 5 m cable, GX12 4-pin female connector fitted
- Test certificate
- Calibration solution (optional, specify at order)
Quality and warranty
- IP68 sealed body, ABS and ABS/PC alloy wetted parts
- 72-hour burn-in and stability test on every unit before shipment
- Warranty: 1 year from date of sale, excluding damage from improper use
Handling and maintenance
- Cleaning interval is set by the water, not by the clock - a clean RO permeate line may go a year, a scaling cooling circuit a month.
- Clean with a soft brush, then rinse with distilled water. Recalibrate after every clean.
- Do not scratch the electrode surfaces. Unlike the inductive DODO AQUA SAL, this is a contacting cell and its geometry is the calibration: an abraded electrode has a different cell constant.
- Do not use abrasive powders or wire wool on the electrodes.
- Check the cell for trapped debris whenever a reading drops suddenly and stays low.
Frequently asked questions
Does DODO AQUA EC work with a PLC, SCADA or a third-party data logger?
Yes. DA-EC is a standard RS-485 Modbus-RTU device at 9600 baud, 8N1, so any Modbus master can read it - PLC, DCS, SCADA or a paperless recorder. The full register map is published in the datasheet, and the sensor can be ordered with bare leads instead of the GX12 connector for terminal-block wiring. There is no proprietary driver and no lock-in.
What is the default Modbus address of DA-EC?
6. The address is changeable in the field over the bus, so several sensors can share one RS-485 pair as long as each has a unique address.
How do I connect DODO AQUA EC to DODO LOGGER?
Screw the fitted GX12 4-pin connector onto the logger's Modbus RS-485 socket - no stripping, no terminal block, no tools. DA-EC is in the logger's no-code sensor library, so an installer selects it in the web interface and it begins logging to microSD and publishing to the DODOTiK Platform and the DODOLINK app. No firmware reflash, no backend change.
What does DA-EC measure, and how accurately?
Electrical conductivity: Six ranges - see Ordering information, accuracy ±1 % of reading; Total dissolved solids (TDS): Range-dependent, accuracy ±1 % of reading; Temperature: 0-65 °C, accuracy ±0.3 °C.
How do I order DA-EC, and what does it cost?
DA-EC is sold direct and through distributors. Pricing depends on configuration and quantity, so request a quote with the order code and the quantity you need and DODOTiK will come back with export pricing and volume tiers. Available configurations: DA-EC-K001-20U; DA-EC-K001-200U; DA-EC-K01-5K; DA-EC-K1-20K; DA-EC-K1-200M; DA-EC-K1-400M; …-L10 / -L20; …-BL.
Is there anything to watch out for when specifying DA-EC?
Range and cell constant are factory-set; neither can be changed in the field. The slope-calibration scaling depends on the range the unit was built for.
More from DODO AQUA
Request a quote for DA-EC
Sold direct and through distributors. Tell us the order code, the quantity and the destination country and we will come back with export pricing, volume tiers and lead time.