Brand: ABB
Category: Other
Document Type: Manual
Language: EN
Available Languages: EN , ES
Manual for ADS420
Uploaded: April 20, 2026, 7:51 p.m.
Warranty Information
No specific warranty period is mentioned in the provided document.
The ADS420 is an optical dissolved oxygen sensor designed for accurate DO data measurement. It is rugged and reliable, utilizing advanced optical technology. The sensor is compatible with ABB multi-input transmitters like AWT420 and AWT440, featuring 'hot-plugging' capability for easy replacement without powering down the transmitter. It can also be used with an optional EZClean unit for automatic in-situ cleaning. The manual details sensor setup, calibration procedures (1-point and 2-point), maintenance (cleaning), and diagnostics for troubleshooting potential issues. Key operations include installation, calibration using water-saturated air and oxygen-depleted solutions, and routine cleaning of the SmartCap, lens, and sensor body.
Troubleshooting and error codes
| Diagnostic message | Cause | Recovery action |
|---|---|---|
| S(n): PT failure | The temperature sensor has failed, or its connections are open-circuit or short-circuit. | 1. Inspect sensor/temperature sensor for damage. Replace if damaged. 2. Cycle power to the transmitter. 3. Contact service if failure persists. |
| S(n): D.O. Conc Meas Error | The DO sensor cannot provide a valid dissolved oxygen measurement due to a sensor error. | 1. Cycle power to the sensor. 2. Contact service if failure persists. |
| S(n): %Sat Meas Error | The DO sensor cannot provide a valid % saturation measurement due to a sensor error. | 1. Cycle power to the sensor. 2. Contact service if failure persists. |
| S(n): Calibrating | Sensor calibration in progress. | This diagnostic clears when calibration is complete. |
| S(n): Internal Comms Error | Error in communication between the sensor and the SmartCap. | 1. Ensure the SmartCap is installed and correctly seated. |
| S(n): Cap Removed | The SmartCap has been removed or is not recognized. | 1. Ensure the SmartCap is installed correctly. |
| S(n): Cal Failed | Most recent sensor calibration failed. | 1. Ensure sensor is clean and fully submerged. 2. Recalibrate. 3. Consider replacing sensor if failure persists. |
| S(n): User Cal Expired | Recalibration is required; sensor deteriorates over time. | 1. Perform a calibration. |
| S(n): Factory Cal Expired | Recalibration is required; sensor deteriorates over time. | 1. Perform a calibration. |
| S(n): Sensor Warm-up | The DO sensor is warming up and cannot provide a valid measurement yet. | Clears when internal electronics stabilize. Contact service if persistent. |
| S(n): Sensor Warning | PV measured from the DO sensor does not meet normal quality criteria; moderate damage or end of lifespan reached. | 1. Inspect sensor for damage. 2. Clean sensor and optical lens if in good condition. 3. Contact service if damage or persistent issues. |
| S(n): Cap Expired | SmartCap has reached or exceeded its expiry date; accuracy degrades. | 1. Replace the SmartCap. |
| S(n): Replace Cap | SmartCap expiry date approaching (within 4 weeks); accuracy degrades. | 1. Replace the SmartCap. |