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O2I-FLEX Oxygen Sensor Interface Electronics

The O2I-Flex Oxygen Sensor Interface Electronics provides the electronics necessary to power and control SST’s range of zirconium dioxide oxygen sensors.

The O2I-Flex oxygen sensor interface electronics can be user configured to output measuring ranges of 0-25% O₂ and 0-100% O₂. The entire measurement range is linear in both cases and offers three output options 0-10V, 4-20mA and RS232 comms interface.

The O2I-Flex can be calibrated in fresh air (20.7% O₂) or in any other known O₂ concentration by either an automatic or manual external trigger or via an on-board push button switch. The electronics offer power and sensor operating LEDs and removable polarised screw terminals for easy wiring.

The adaptive software filtering provides a fast sensor response coupled with a stable oxygen output.

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Part Numbering Guide

TECHNICAL SPECIFICATIONS

Supply voltage 24Vdc +/- 10%
Supply current 600mA max. at 24Vdc
Digital output RS232
Analogue output 4-20mA; load 600Ω max or
0-10Vdc; load 10kΩ min
Temperature limits
    Storage -10 to 70⁰C
    Operating -10 to 70⁰C
Oxygen pressure limits¹ 1 to 1000mbar

OUTPUT VALUES

Oxygen range (analogue output)³ 0.1² to 25% O₂ or
0.1² to 100% O₂
Oxygen range (RS232 output) 0.1² and 100% O₂
Accuracy after calibration⁴⁵ 1% O₂
Repeatability after calibration⁴ 0.5% O₂
Output resolution
    Analogue 4-20mA 0.01mA
    Analogue 0-10Vdc 0.01V
    Digital RS232 0.01% O₂
Response time
    Fast response sensor connected:
    Standard response sensor connected:
Initial warm up time (until stable output) 5-10 mins
Output inactive start up delay (heater warm up) 60s

OUTLINE DRAWINGS

outline-drawing

¹Sensor and interface for correct barometric pressure compensation.
²Prolonged operation below 0.1% O₂ can damage the sensing element.
³Range selectable by altering the position of the jumper links on the PCB, refer to datasheet for details.
⁴Assuming barometric pressure (BP) remains constant.
⁵As the O₂ sensor measures the partial pressure of oxygen (PPO₂) within the measurement of gas deviation in the BP from the present during calibration will cause readout errors proportional to the change, e.g. if the sensor reads 21% O₂ at 1013.25mbar and the BP increases by 1%, the sensor readout will also increase by 1% to 21.21% O₂.

ELECTRICAL INTERFACE

 

Electrical-connections

Pin Assignment
1 Sensor heater GND (1)
2 Sensor heater + (2)
3 Sensor sense
4 Sensor common
5 Sensor pump
6 24Vdc +/- 10%
7 GND
8 4-20mA output
9 0-10Vdc output
10 Calibrate
11 Cycle
12 RS232 Tx
13 RS232 Rx

FEATURES

  • Provides the electronics necessary to power and control SST’s range of zirconium dioxide (ZrO₂) sensors
  • Externally triggered automatic or manual calibration. Calibration can also be initiated via an on-board push button
  • Power and sensor operating LEDs
  • Removable polarised screw terminals for easy wiring

BENEFITS

  • Adaptive software filtering provides a fast sensor response coupled with a stable oxygen output
  • High accuracy linear output
  • Can be calibrated in fresh air (20.7% O₂) or in any other known O₂ concentration
  • This field is for validation purposes and should be left unchanged.