Dräger 8000 IC Function Description page 22

jumper in the plug whenever the sensor is plugged in. This voltage is sensed by the
microprocessor via a port.
2.2.2.9 Oxygen sensor A (41A), Inc. 8000 IC only
The output voltage of the oxygen sensor cell A is adapted to the ADC by the input amplifier
stage (33A). The output voltage of 0.0 mV to 120 mV is amplified to 0.0 V to 4.76 V.
2.2.2.10 Oxygen sensor B (41B), Inc. 8000 IC only
The output voltage of the oxygen sensor cell B is adapted to the ADC by the input amplifier
stage (33B). Its amplification factor is reduced by the factor of 2.75 compared to the oxygen
sensor A. This different amplification factor is later compensated for by software. After analog
to digital conversion comparing signal B to the signal of oxygen cell A has to show the
discrepancy in values to be within a certain window. Errors because of false addressing of the
multiplexer are clearly detected. Resolution: 0.0 mV to 120 mV input voltage = 0.0 V to
1.73 V output voltage
2.2.2.11 O2 comparators (30A and 30B), Inc. 8000 IC only
In addition to the microprocessor controlled check of the oxygen cell each cell is monitored
with an individual comparator. These comparators are set to a trigger level of approx. 7 mV. If
the output voltage falls below this limit, the relay (18)and the oxygen valve (3) are switched off
and the oxygen sensor alarm is activated.
2.2.2.12 Detection of sensor head position (43), Inc. 8000 IC only
The position of the sensor housing at the hinge is sensed by two micro switches installed in
the sensor housing and is evaluated via a PIA on the Motherboard PCB.
2.2.2.13 Humidity sensor (42), Inc. 8000 IC only
The output voltage of the humidity sensor is switched to the ADC via a voltage divider (34).
Resolution: 0 to 100 % relative humidity = 0.55 to 4.31 V
Function Description
6141.22X Incubator 8000 IC/SC/NC 09.99 Page 22 of 49