User Manual

Optical pH Sensors | User Manual
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1. The end of the sensor lifetime is reached and the sensor needs to be replaced.
2. The sensor is connected to the wrong channel at the multi-channel
FireSting pro
3. In case of sensor spots: the positioning of the optical fiber on the sensor spot is not
correct.
4. The vessel wall is too thick in the case of sensor spots.
In this case, please try to increase the LED intensity as maybe the vessel wall is too
thick or the sensor is altered to a high extend.
To do this, go back to the Settings and increase the LED Intensity.
A higher LED intensity leads to a higher sensor signal. If the warning still shows up after
setting the LED intensity up, please increase it further until the calibration is possible.
3.6.2 “Warning: Sensor signal out of range”
The reason for this can be:
1. The end of the sensor lifetime is reached and the sensor or sensor screw cap needs
to be replaced.
2. The calibration buffer does not exhibit the correct pH value.
3. The pH of the sample is out of the dynamic range of the sensor.
Be sure that you use the correct pH buffer. The allowed pH buffers are: pH <3 for the first
calibration point, pH >10 for the second calibration point, pH of the pKa value of the
sensor for offset adjustment (pH 7 for a PK7 sensor, pH 8 for a PK8 sensor).
3.6.3 “Warning: Wait for steady state”
The reason for this can be:
1. The sensor is not equilibrated yet. Wait for a few minutes longer.
2. The temperature of the sample is changing.
3.6.4 “Warning: Bad temperature measurement”
The reason for this can be:
1. No temperature sensor is connected
2. In case of optical temperature spots: The fiber is not located at the sensor spot
anymore.