Fresenius Medical Care 4008 E Technical Manual page 334

Speed and flow
The processor emits the speed via port P1.1 and the flow via port P1.2 to the dialysis monitor.
Pressure measurement
The differential measuring amplifier for the pressure transducer is formed by IC 6 (1/2/3) and IC
6 (5/6/7). Via the A-D converter input AN7, the measuring signal is read in by the processor and
calibrated to zero point and slope via the software. Subsequently, the measuring signal is pulse-
width-modulated via port P1.3 and emitted to the monitor via a following D-A converter IC 11 (5/
6/7).
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Fresenius Medical Care 4008 4/09.03 (TM)