Fresenius Medical Care 4008 E Technical Manual page 563

Status indicator LEDs (circuit diagram 4/6)
All status indicators as well as the condition indicator are switched by means of IC 35 and IC 38
(CS16, CS17).
Both modules are
– connected to the brightness control by R42,
– not connected to the brightness control by R43 (maximum brightness).
The I/O LED (power on/off) is directly connected to the 5-V supply network.
Alarm indicator LEDs (circuit diagram 5/6)
All alarm indicators are energized by IC 39 and CS18. The key click is controlled by output 19 of
IC 39 via IC 40/5.14.
Bar graph displays for arterial and venous pressure (circuit diagram 2/6)
IC 15, IC 16, and IC 17 are provided as data memories for the arterial bar graph display, whose
30 LEDs are organized within a 5x6 matrix. The 5 lines are directly energized via the emitter
sequence IC 21 by data buses DB0 to DB4 and the 6 columns via the 8-out-of-3 decoder IC 31 by
data buses DB5 to DB7. The actual value (CS1) is stored by IC 15; the upper limit (CS2) is stored
by IC 16; and the lower limit (CS3) is stored by IC 17. The respectively applicable LED is
energized via the clock inputs CL1, CL2, and CL3. The clock pulses of CL1 have a longer duration
than those of CL2 and CL3. Thus, the actual value is represented more brightly than the limits.
IC 18 (CS4), IC 19 (CS5), and IC 20 (CS6) are provided as data memories for the venous bar
graph display. The working method of this display is identical with that of the arterial bar graph
display.
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Fresenius Medical Care 4008 4/09.03 (TM)