Power Pack Pcb - Dräger 8000 IC Function Description

m. Humidity sensor, 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
n. Reference for ADC
The reference voltage for the ADC is based on the +15 V and the -15 V supply voltage for the
analog components. This allows monitoring the accuracy and function of the voltage regulators
for these voltages.
o. Multiplexer
The eight to one multiplexer selects the input signals for the ADC and is addressed by the
outputs of the PIA. The addressing of the multiplexer is also reread by the PIA to detect
addressing errors. Any addressing error will lead to an Inop alarm.
p. A/D Converter
The A/D converter digitizes the analog signals with a resolution of 12 bit. The 12 bit words are
read by two consecutive 8 bit data readings.
3.2.7

Power Pack PCB

3.2.7.1 Intended use
PCB Power Pack serves the rectification of the supply voltages +15 V and -15 V. By means of
half-wave monitoring a power fail or mains interrupt is recognized. If the mains voltage fails a
battery-buffered audible alarm is given by a beeper on the PCB and an optical alarm is given
by an external LED. During operation the beeper is driven by an external signal.
6141.22X Incubator 8000 IC/SC/NC
Function Description
09.99 Page 40 of 49