Zirconia-Oxygen-Sensor-System

Supported Applications

The SST Zirconia Oxygen Sensor System is designed for measuring oxygen concentration in gases using zirconium dioxide (ZrO₂) sensing technology. The system comprises an interface board and a sensor probe, providing long-life non-depleting measurement without the need for reference gas or temperature stabilization.

Operating Conditions & Performance

The series supports oxygen concentration measurements across two primary ranges: 0.1% to 25% O₂ and 0.1% to 100% O₂, with a resolution of 0.01% O₂. Accuracy is specified as ±0.2% O₂ after calibration verification or 0.5% O₂ depending on the configuration. The sensor operates within a process temperature range of -100°C to +250°C and supports absolute pressure ratings from 260–1260 mbar.

Response time is documented as less than 4 seconds (< 4s). Power requirements vary by output type: RS485 variants operate on 8–28VDC, while analogue variants require 20–28VDC. Load resistance limits are specified as 600Ω max for the 4–20mA signal and 10kΩ min for the 0–10VDC output.

Configuration Options

The system is configurable with different interface boards, sensor probe lengths, and electrical outputs to match specific installation needs. Key capabilities include:

• Output Signals: RS485 (Modbus RTU), 4–20mA current loop, or 0–10VDC voltage.
• Sensor Probe Lengths: Available in 28mm, 45mm, and 55mm options with M18x1.5 screw mounting.
• Interface Board Dimensions: The PCB measures 62 mm length x 56.75 mm width x 1.6 mm thickness.
• Cable Connection: A cable with multi-colored wires terminates in a connector to the interface board, utilizing a terminal block with 9-pin connections for sensor heater, pump, sense lines, power, and output signals.

The RS485 variant supports configurable communication settings including Address (default: 1), Baud Rate (default: 9600), Parity (None), and Stopbits (1). The interface board includes integral pressure compensation to extend calibration intervals. New sensors require a burn-in period, during which drift may occur.

Key Product Differences

The series is differentiated by the selected measurement range and output signal type on the interface board:

• OXY-LC-485: Measures 0.1% to 100% O₂ with Modbus RTU output; heater voltage is configurable.
• OXY-LC-A25-455 / V25-455: Measure 0.1% to 25% O₂, available in 4–20mA (A) or 0–10VDC (V) outputs with a fixed heater voltage of 4.55VDC.
• OXY-LC-A100-455 / V100-455: Measure 0.1% to 100% O₂, available in 4–20mA (A) or 0–10VDC (V) outputs with a fixed heater voltage of 4.55VDC.

Sensor probes are identified by part numbers such as O2S-FR-T2-18BM-A, B, and C corresponding to the 55mm, 45mm, and 28mm lengths respectively. The maximum distance from sensor to interface is limited to 1.1m unless otherwise agreed with SST.

Media Compatibility Warning: Zirconium dioxide sensors are damaged by silicone vapours (organic silicone compounds) found in RTV rubbers and sealants; these must be avoided. Chemical cleaning agents should not be used on the sensor.