The oxygen sensor MF-Oxy measures the oxygen partial pressure directly in the gas mixture, the absolute oxygen content.
If necessary, during operation, it monitors its own function and reports in case of hardware malfunction. Moreover it offers a function for diagnosis.The sensor can be calibrated without reference gas in atmospheric air.
The MF-Oxy was designed especially for the automatic control of combustion plants, as well as for oxygen measurements in difficult to reach areas or in self-contained systems (ventilation tubes, containers, etc.). Its signals can also be transmitted up to 300 meters, over great distances.In two variants it can be used at maximum exhaust temperatures of +250°C and +350°C.
A fail-safe operation can be realized by an additional, independent digital output.
Measuring ranges, temperature ranges and product specifications
The oxygen sensors of the product family MF-Oxy are available for a measuring range from 0.1 to 25 Vol.-% or 0.1 to 100 Vol.-% oxygen. For operation at a temperature of up to +250°C, probe tubes of 120 mm, 220 mm, 400 mm and 800 mm can be selected; at process temperatures up to +350°C, only the rod variant of 120 mm is omitted. Alternatively the measuring device offers an analog interface with 4 - 20 mA or 0 - 10 V and is also equipped with an independent digital output. The product is equipped as standard with a full sinter cab. On request, also a inside sinter can be installed, which makes the system more resistant to impurities. However, due to this change of specification the reaction time is increased.
Diagnostic function
The measurement signal output is given from two independent channels. The output signal of the analogue channel is linear, between 4 and 20 mA (alternatively 0.1 to 10 V). The digital channel carries a pulse-width modulated alternating signal (high phase 5V, low-phase 0V). The length of the low-phase is the benchmark for the oxygen concentration to be computed in the downstream unit (e.g. limit monitor GWZ). The times are linear and system specific. The monitoring of both channels allows a fail-safe operation without using a second sensor.
Functional Test
The probe is designed so that it can check the operation during its proper functioning. For this the test pin is applied to +24 V DC. The test simulates to the probe a 20% lower oxygen concentration. This change must reflect equally in the analog channel.
Certifications
The oxygen measuring device MF-Oxy complies with the generic standards DIN EN 50270: 2015-5 type1 and type2 and DIN EN 61326-1: 2013-07 and so with the EMC-directives 2014/30/EU.
Maintenance and Service
The device is delivered already calibrated. The interval of the maintenance meets the safety requirements. We recommend at least a six-monthly monitoring and a five-year replacement cycle. The device can be calibrated on fresh air and is supporting electrical as well as manual calibration. For the electrical calibration the test pin is set to +24 V DC. The probe calibrates autonomously on fresh air, within a tolerance range of 10%. Outside the tolerance range of the sensor it can be calibrated manually. Manual calibration is performed by means of a potentiometer inside the housing.
