Dräger 8000 IC Function Description page 37

3.2.6.3 Detailed description of function blocks
a. air temperature sensor
b. over-temperature sensor
c. over-temperature comparator
d. test over-temperature comparator
e. skin temperature sensor
f. test skin temperature sensor circuit
g. skin temperature-sensor alarm
h. skin temperature sensor detection
i. 02 sensor A
j. 02 sensor B
k. 02 comparator
l. detection of sensor head position
m. humidity sensor
n. A/D converter reference voltage
o. Multiplexer
p. A/D converter
a. air temperature sensor
The air temperature sensor is part of the feedback loop of an operational amplifier and
supplies an outlet voltage proportional to the temperature which is adapted to the input voltage
range of the A/D converter via a second amplification stage. Resolution: 0.0 °C to 60.0 °C =
0.0 V to 5.0 V.
b. over-temperature sensor
The over-temperature sensor is installed in the same housing as the air temperature sensor
and serves as redundant measuring system for the air temperature. The amplification factor
and thus the output signal is not equal to the output signal of the air temperature sensor. The
air temperature and the over-temperature sensor are monitored by the software. If the
measured temperatures deviate by more than 0.5 °C a sensor alarm is given. The over-
temperature sensor is part of the feedback loop of an operational amplifier and supplies an
outlet voltage proportional to the temperature which is adapted to the input voltage range of
the A/D converter via a second amplification stage. Resolution: 0.0 °C to 50.0 °C = 0.0 V to
5.0 V.
c. over-temperature comparator
The output voltage of the over-temperature sensor is additionally evaluated by a comparator
whose response limit is set to 40.0 OC. Independent of the microprocessor system in the event
of over-temperature the heating is switched off via this comparator and thus the device is put
6141.22X Incubator 8000 IC/SC/NC
Function Description
09.99 Page 37 of 49